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www.archetype.co.uk 3 in association with 2009 9 781904 982487 VOLUME 3 2009 Sailing through history: conserving and researching a rare Tahitian canoe sail Tara Hiquily, Jenny Newell, Monique Pullan, Nicole Rode and Arianna Bernucci

Summary The British Museum has a unique canoe sail in its collection, which is likely to be the only Tahitian canoe sail (‘ie) to have survived from the early era of sailing canoes. This sail is just over 9.5 metres long by 1.5 metres wide, curving at the top and bottom, and is characteristic of the Society Islands. It dates from either the eighteenth or early nineteenth century. It is constructed from finely plaited mats of cut pandanus leaf, with fibre loop fasteners secured along its edges, and has remains of the ropes that ran up each side of the sail and were used to tie it to a mast. Canoes and sails of this type were observed and documented by early European voyagers. Islanders and Europeans were fascinated with each other’s maritime technology and collected techniques and examples from each other. Several canoes and sails from the central Pacific were brought back to Britain and France in the eighteenth century and one of the richest collections of Polynesian maritime technology is held at the British Museum. In 2007 and 2008, the Museum’s Tahitian sail was assessed, conserved and documented in exceptional detail. Conservation included the removal of soiling, crease reduction and the introduction of two types of support: lengths of toned mulberry paper were woven to support smaller, weak areas and holes, while strips of Tyvek® were used to maintain plait alignment over large areas of loss, particularly during rolling and unrolling. The collaboration between curators and conservators at the British Museum and a Tahitian curator was an important part of the conservation project and resulted in the creation of a large amount of information about this sail that now serves as a resource for a variety of interest groups, many from the Pacific, who are now able to access the sail without compromising its long-term preservation.

INTRODUCTION (TH), who is a specialist in the history and technology of Polynesian canoes from the Musée de Tahiti. Together with The canoe sail from Tahiti in the collections at the British the conservation and resulting close technical study, the Museum (Oc1999,Q.139: Figure 1) appears to be the only collaboration greatly enhanced the understanding of this such sail to have survived from Tahiti’s sailing canoe era. particular sail. Tahitians stopped making sailing canoes in the 1840s, when News of the conservation and examination project spread the French colonial government instituted a ban on inter- rapidly, and scholars, journalists and Polynesians working island travel. The sail probably reached the Museum in the on reconstructing voyaging canoes have been able to benefit late eighteenth or early nineteenth century. It had been in from this unique opportunity to view a complete Polynesian storage in the Museum’s reserve collection until its signifi- sail constructed with traditional materials and techniques, cance was recognized and a programme was initiated that where previously they relied largely on guesswork. led to its assessment, conservation and documentation in 2007–2008. Prior to conservation, the size and fragile condition of the sail had rendered it impossible to unfold safely, which significantly limited examination and analysis. DESCRIPTION OF THE SAIL After conservation, the sail remains inherently very fragile, but can now be made available for occasional study. The sail is tall and narrow, measuring 9.68 m high by 1.53 During this project, British Museum curators and m wide, and curves inwards at the top and bottom ends. Its conservators were fortunate to work with one of the authors form matches the illustrations made by the artists on Cook’s

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and Bligh’s early voyages to Tahiti, in particular those by the artists S. Parkinson, W. Hodges and J. Webber on the three Cook voyages and by Lieutenant George Tobin on Bligh’s Providence in 1792, Figures 2–4. The sail’s dimensions, with a width to height ratio of one to six, accord with the observations of these visitors. The sail is constructed from three large mats, as well as smaller pieces of various shapes and sizes, each made from plaited Pandanus tectorius leaf (the Tahitian term for which is fara).1 These have been stitched together with running stitches approximately 3–4 cm long in a two Z-plied cord made from the internal bark of Hibiscus tiliaceus (Tahitian term purau). The outer edges of the mats have been folded over and stitched into a sleeve that runs along the entire perimeter of the sail. This sleeve encases a thick (approximately 3 cm diameter) three Z-plied rope made from purau fibre, Figure 5. The rope, strengthening the sail at the edges, extends outwards at the top and bottom ends, while a separate section of rope extends from the mast edge of the sail roughly two-thirds of the way up the sail, Figure 6. These three thick purau ropes are a remarkable feature of this sail. The two lower lengths most likely served to fasten the sail to the mast, but the topmost length was probably used to fix a long rope of black feathers. Along the edges of the sail, numerous small loop fasteners are tied at regular intervals, except for a length between the end of the spar (which ran in parallel with the mast) and the top of the mast, where there are no fasteners. These loops were made either from purau or from coconut palm (Cocos nucifera) fibres, the Tahitian term for which is nape. Tied to several of these loops fasteners are remains of two-ply purau fibre cord lengths, which would have helped fix the sail to the mast and the spar. The sail would probably have been rigged on one side to a straight mast reaching slightly over halfway up its height and on the other to a J-shaped spar extending along its entire length, Figure 6. Extra stitching figure 1. Tahitian sail Oc1999,Q.139 (during treatment)

figure 2. E. Rooker, A view in the island of Ulietea [Ra‘iatea] with a double canoe and a boathouse, after drawings by Sydney Parkinson [12; Plate 3 (vol. II)]. Image: National Library of Australia, Canberra, nla.pic-an.9184895

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figure 4. Sydney Parkinson, Canoe of Ulietea [Ra‘iatea], August 1769; note that the people are not drawn to scale. From ‘A collection of drawings made in countries visited by Captain Cook in his first voyage 1768–1771’, British Library, Ms Add 23921 f. 20. Image: National Library of Australia, Canberra

with a cord made from nape, in this case a three-strand flat plait, has been added along the edge without loop fasteners to strengthen this section, which would not have been reinforced by wood when the sail was rigged. The pandanus leaf has been split longitudinally in strips and plaited together in a plain bias pattern, now rather distorted. The upper surface of the leaf is characterized by figure 3. George Tobin [va’a motu], pen and wash drawing, Tahiti, 1792. Location of original not identified. Reproduced from Lee, I., a smooth glossy cuticle while the lower surface is ribbed Captain Bligh’s second voyage to the South Sea, Longmans Green and and matt. The strips have been plaited predominantly, but Co., London (1920). Image: National Library of Australia, Canberra not exclusively, with the same leaf surface facing to one

figure 5. Construction features of the sail

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Considerable sections of the sail remained in remark- ably good condition with the pandanus leaf clean, intact and retaining a degree of suppleness and flexibility. However, there were also large areas of damage where the leaf was extremely brittle and had broken, resulting in either the loss of one element of the plait structure or both. The folding of the sail in storage had significantly deformed it, and there were strongly set folds at intervals across its width that prevented it from opening flat, Figure 7. Large splits had formed along these fold lines, and there were many areas of loss: at least 33 areas had holes spanning 10 cm or more. Not all areas of loss corresponded with folds or were in areas where the surrounding pandanus was particularly brittle, and may have occurred during use of the sail. Once one element in the plait structure had broken this clearly had a significant impact on the structural stability of the surrounding area, since the plait elements could then easily move out of position and leave the broken ends vulnerable to further damage. Many fragments, both plaited sections and individual leaf strips, were found detached and wrapped up with the sail bundle, Figure 8. The sail was heavily soiled on both sides with fine, black, sooty particulate matter, typical of urban pollution. The level of soiling could be correlated to the way in which the sail had been folded in storage, with the heaviest layer on the outermost surfaces. The level of soiling also related to the condition of the pandanus leaf; in the heavily blackened areas the plant fibres were rigid and brittle, while the figure 6. Diagram of posited sail rigging (not to scale) less soiled areas remained surprisingly pliable.

Treatment side of the sail, Figure 5. It is possible to speculate an inten- tional purpose behind this – perhaps to keep an even and The primary aim of the treatment was to enhance the pres- flat tension on the sail, or for decorative effect. The width ervation of the sail in long-term storage. However, in light of the cut strips varies from mat to mat and is in the range of the interest that the conservation of the sail began to 3–5 mm. This difference produces mats that vary in deli- engender, particularly in communities physically distant cacy and fineness, suggesting they may have been plaited from the UK,2 there was a desire to enable the greatest by more than one hand. possible access to the information contained in the sail without compromising its preservation. Much soiling was removed using low-powered vacuum suction and vulcanized latex rubber sponges. After both CONSERVING THE SAIL sides of the sail had been cleaned in this way, the sail was humidified using contact humidification; dampened cotton Condition cloth was used to introduce moisture vapour through a Gore-Tex® membrane (a polytetrafluoroethene and poly- The Tahitian sail arrived in the organic artefact conserva- ester laminate). Temporarily increasing the moisture tion studios folded into a ‘bundle’. The scale of the under- content of the plant fibre made it more flexible, facilitating taking involved in conserving such a large and fragile object the reshaping of folds and distortions. Heavy blankets were cannot be understated, and detailed scheduling of resources used to hold the realigned and flattened sail in place as the and forward planning, including staffing, materials and relative humidity returned to ambient conditions. studio space was essential. For example, it required ten Two approaches to the physical stabilization of the tables, which almost entirely filled the studio, to accommo- sail were taken. The first aimed to hold together and date the sail’s full length, so that manoeuvring procedures secure within the plait structure any broken leaf strips, such as turning that are usually straightforward required thus preventing their loss. The second aimed to provide careful step-by-step planning. structural integrity to the sail on a larger scale, helping to

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figure 7. The top end of the sail before conservation, showing the extensive creasing across the width of the sail

figure 8. Sections of brittle and split pandanus leaf address the dimensional instability and stresses caused by Figure 9. Strips of a similar width to the original leaf strips the larger areas of complete loss. were cut from colour-matched 11 g.m–2 tengujo mulberry Breaks in the leaf strips, small holes, and the edges of any paper. Liquitex® acrylic paints diluted in water were used large areas of loss where projecting fragments of pandanus to tone the paper and gave a subtle sheen that matched the leaf were moving or breaking off, were all strengthened by slightly glossy leaf. The tonedtengujo papers were lami- introducing support elements into the plait in these areas, nated with 10% Lascaux 498 HV adhesive (a thermoplastic

5 TARA HIQUILY, JENNY NEWELL, MONIQUE PULLAN, NICOLE RODE AND ARIANNA BERNUCCI

figure 9. Using a ‘needle’ cut from heavyweight Melinex , a mulberry paper support strip is woven across a weak area. To the left of the damaged area, already incorporated repair strips are® visible

figure 10. After securing the edges with toned paper strips, lengths of cut Tyvek maintain the plait alignment across the large area of loss ®

acrylic polymer dispersion based on methyl methacrylate Using ‘needles’ cut from heavyweight polyester film and butylacrylate). By laminating together two sheets of (Melinex®) and tweezers to draw them through, the paper paper it was possible to recreate the subtle colour variations support strips were woven into the structure on top of the on either side of the original leaf strips. original pandanus strips, bridging across breaks and looping

6 CONSERVING AND RESEARCHING A RARE TAHITIAN CANOE SAIL round to anchor broken leaf ends. The paper supports were detailed documentation were undertaken, including the secured at points to the pandanus leaf below with a dot production of descriptions, diagrams, detailed measure- of arrowroot starch paste adhesive, applied with a small ments and extensive photographs, all of which have been brush. made available through the Collection Database on the The use of long-fibred mulberry papers in the repair of British Museum website.4 basketry is well documented, and is used regularly at the The various documents will enable all interested parties British Museum [1, 2]. It was found to be a very compatible to have access to the information, including academic material with the pandanus: it gave sufficient strength, was researchers, those involved in Polynesian canoe recon- fine enough to insert within the plait, blended well visually, structions, museum curators and conservators. The rich and was flexible enough to conform to the leaf and preserve visual information ensures that access is available to those the natural movement between individual elements within who may not read English as their primary language. It is the weave structure. of particular value, as the sheer size and fragility of the sail The larger areas of loss had a significant impact on the precludes its display in the near future, although occasional overall stability of the sail, making the surrounding areas study is possible, if cumbersome. vulnerable to further damage, particularly when it was being handled or rolled, when they tended to project out of alignment. As the sail was to be rolled for storage and it was expected that it would be unrolled occasionally for POLYNESIAN CANOES AND SAILS study, this posed a problem. To hold the broken edges in register and maintain the The design and construction of canoe sails have shared overall plait alignment of the sail, ‘bridging’ elements were many points of similarity across Polynesia, a cultural– added. Cut strips of Tyvek® (a non-woven high density geographic region covering the eastern and central Pacific, polyethylene) were stretched across the area of loss at from Hawaii in the north to Rapanui (Easter Island) in the spaced intervals and secured either side by weaving along- east and across to New Zealand in the south. A number side the pandanus leaf for short sections, Figure 10. Tyvek of attempts have been made to reconstruct ancient was chosen in place of the mulberry paper for its additional Polynesian canoes relying on information drawn from strength; a narrow strip can successfully bridge two areas contemporary traditional building knowledge, historical across a large space without tearing. The supports were left accounts and drawings. However, very little is known uncoloured, and were secured by weaving the ends back about ancient fibre sails because they disappeared very on themselves, rather than by adhesion [3].3 There was no soon after the first contacts with Europeans. The analysis intention to infill the missing areas, only to stabilize the sail of the few surviving sails that were collected at the time, structure and protect vulnerable surrounding areas. These when the canoes were still in use, is therefore crucial to supports have worked well to maintain plait alignment understand how they were made and their role in sail during rolling and unrolling. Inserting the supports at canoe navigation. spaced intervals was inevitably faster than the more closely Polynesians from the Society Islands (Tahiti and spaced coloured paper supports, and the white colour of surrounding islands) referred to the sails of their canoes the Tyvek gives a visual indication of the inherently fragile with the term ‘ie. This term can also be found in Tuamotu, nature of the sail during examination. As no adhesive was while on Mangareva kie, a variant of ‘ie, is used. Nearly used, the Tyvek strips can easily be removed should the sail everywhere else (notably Hawaii, New Zealand, Samoa, ever go on display, and further cosmetic infilling could be Wallis and Rarotonga) the terms rä or lä are in use [4]. carried out if this was ever deemed to be appropriate. Polynesian sails were finely woven out of pandanus fibre, The pandanus leaf remains extremely brittle and the work that was carried out exclusively by women, while sail is, therefore, very prone to continual fresh, small-scale the ropes and lines used in conjunction with them were breaks occurring, particularly during handling. This makes made by men. Similarly, all seafaring carpentry work was it unlikely that the sail itself can be regularly or repeat- carried out exclusively by men and under the supervision edly rolled and unrolled in its entirety without causing of a master called Tahua tarai va’a [5]. damage. In the Society Islands, the sail on every canoe was based Prior to long-term storage, the sail was rolled around a on a single model and it is even likely that they were also padded, acid-free card roller and extra padding was intro- of similar size. This type of sail, referred to as the ‘simple duced to accommodate the undulations and unevenly triangular sail’, was quite widespread throughout eastern distributed raised areas of sail. Polynesia (the area including Hawaii and the Society and Marquesas Islands) and was also found in New Zealand. Society Island canoes were tacking canoes, with the sail Information resource fixed in position and the prow of the canoe always facing forward. In other parts of Oceania, double-ended canoes, During the conservation process conservators had the first referred to as shunting canoes, could sail in both directions: opportunity to examine the sail closely. Various forms of there was a step at each end and the apex of the sail was

7 TARA HIQUILY, JENNY NEWELL, MONIQUE PULLAN, NICOLE RODE AND ARIANNA BERNUCCI moved from one end of the canoe to the other with the rolling up the lower section of the sail. When the canoe helmsman positioning himself at the opposite end [6]. capsized, a rope was tied to the end of the boom and one Tacking canoes were fast vessels: one man would pilot of the crew climbed onto the beam to make it sink while the canoe with a steering paddle made of dense wood and pulling on the rope until the sail lifted out of the water, with a very wide blade, while one or two other men were which, with the help of wind, righted the canoe. needed to maintain the balance of the canoe by moving The sails of the Society Islands have been referred along the flat beam or cross-beam that was lashed across to erroneously as ‘crab claw sails’ because drawings the mid-point of the canoe and that extended out over showed a wide curvature towards the top of the mast [6; the water on both sides [7]. The Tahitian type of sail was p. 36]. The examination of the British Museum sail has distinctive in that it was high, very narrow and the upper confirmed – by the location of the fibre loop fasteners section reached a considerable height beyond the mast- along its edge – that this curvature was not intrinsic in head, curving in towards the mast axis when the canoe the form of the sail, but was the shape given to the sail by was moving; for further information on the canoes and the wind. This effect was heightened by the way in which sails of Polynesia, and specifically the Society Islands, see the end of the spar bent back towards the mast, pulled by [8–11]. a rope [7; p. 203]. It is highly likely that this was also the Outrigger canoes with a single sail were called va’a case for Tongan and especially Hawaiian sails, which have motu. They were used for deep-sea fishing and shorter also inaccurately been represented as crab claw sails; the journeys. The only other canoes that were fitted with sails model Tahitian and Hawaiian canoes made by Admiral were the large double-hulled canoes. They had two sails Pâris from 1871 are testimony to this mistake. There are and were of two different types: the tipaerua (a big va’a indeed many Polynesian crab claw sails, but they are on with a double hull) and the pahi. Thetipaerua had hulls amphidrome canoes used by Polynesian populations (like those of the single-sailed va’a motu) that were carved living within Melanesian areas (the Motu living on the out of tree trunks, attached end to end and built up with islands along the south eastern coast of New Guinea and strakes (boards), while the pahi was a complex structure the Taumako in the Santa Cruz Archipelago, east of the of boards pierced and ‘sewn’ together. The cross-section Solomon Islands). through the hull of the tipaerua was U-shaped, but the Across Polynesia, canoes were treated with care and pahi had a sharp keel. The prow of thetipaerua comprised ceremony. The protection of the gods was called upon a projecting horizontal platform and its stern was wide periodically to ensure the ongoing good fortune of the and raised, while for the pahi both the prow and the stern canoe and voyages taken within it. Large war canoes were raised and tapered. Both types of canoes could reach were in many ways sacred and embodied the prestige of a lengths between 16 and 24 m and one or two shelters were community’s chief [13]. Captains Wallis and Cook, after sometimes built on the deck connecting the hulls. These observing the central role of canoes in Tahitian society, canoes usually had two sails set out as in a ketch, i.e. with took canoes hostage when the two groups came into a larger sail on a mast in the front third of the canoe and a conflict, or broke up war canoes in reprisal, guessing how smaller sail in the aft third. Both sails were always placed much impact this would have on the community. on the connecting deck halfway between the two hulls, and a ladder was attached to the mast to help reach the sail and sail sheet (the rope that the helmsman held to make slight adjustments to the angle of the sail, keeping COLLECTING CANOES it close to the wind). Around 1789–1791, James Morrison described a typical From their first encounters in 1767, Europeans and Tahi- Tahitian sail as being equal in length to a canoe (i.e. about tians were fascinated with each other’s ocean-going tech- 10 m), and with a width varying between 1.5 and 2.2 m nologies, and both inspected, asked questions about, and [7; p. 168]. A long rope was attached to the top of the sail measured the other’s vessels [14]. British, French and and decorated with black feathers, presumably to indicate Spanish voyagers often recorded these assessments in wind direction, while a cone-shaped basket of unknown their logs and journals, providing insights into the scale of function was placed at the top of the mast. Captain James values within which one maritime culture viewed another. Cook noted a few years previously that a canoe about The Europeans were, for the most part, impressed by the 10 m long had a mast of around 8 m and a sail a third canoes they observed in Tahiti and other Polynesian longer than the mast [12; p. 223 (vol. 2)]. The sail sheet islands. During his first visit to the island, Cook wrote was attached at the point where the horizontal bamboo lengthy, detailed descriptions of the construction and boom at the foot of the sail met the vertical boom-sprit and uses of canoes. He wrote of the “ingenuity” of the canoe was held by the helmsman; on larger canoes, several men makers and reported enthusiastically on the manoeu- handled the sail sheet. The disadvantage of this type of sail vres of a huge fleet of elaborately carved war canoes that was that it could not be reduced when the winds became he had witnessed, noting that these were manned with strong [7; p. 168], but the Polynesians invented a means “at least fifteen hundred warriors, and four thousand to reduce the overall surface of the sail by detaching and paddlers” [15].

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Collecting samples of these technologies was a way for has a parchment label, commonly used in the eighteenth travellers to record evidence of the practices and skills of century, indicating that it is likely to have reached the particular interest to them as mariners and as a means Museum late that century or in the nineteenth century, of gauging the maritime expertise of those they met in in time to be included in the South Seas Room display. the Pacific, although objects related to canoes were not The label is not conclusively of the eighteenth century, as given or traded in such great quantities as other products the inked text reads ‘Tahiti’, rather than ‘Otaheite’. British of the Society Islands; it is stone adzes, fish hooks, lengths writers tended to use ‘Tahiti’ from the early nineteenth of barkcloth and other, more readily replaced, objects of century, once the use of the Tahitian honorific article ‘O’ everyday life that are the common contents of museum was understood and it was more usual for eighteenth- shelves and stores. Voyagers needed to be in a position to century writers to use ‘Otaheite’. However, at least one offer high value goods, not just the usual trinkets, to trade early commentator, James Morrison, a Bounty mutineer for vessels that had such a central importance in the life who lived on the island from 1788 to 1791, recognized and of the islands. As a result, canoes were collected by those used ‘Taheite’ in his account of the island, which he had with a specialist interest and not just a general desire to finished writing by 1792. The use of ‘Tahiti’ on the label bring back potentially lucrative, eye-catching souvenirs. suggests a slightly later collection and labelling date than There appear to be only two mentions in early naviga- the Wallis or Cook voyages, but Morrison’s example shows tors’ logbooks of the acquisition of a Polynesian sail. The that it is possible that it was labelled in the period between first is when Commodore John Byron seized the sailing the late 1780s and early 1800s, when voyagers, traders and canoes of the inhabitants of Takaroa in the Tuamotu Islands missionaries were spending longer periods on the island in 1765 as a reprisal for their aggressive attitude. The sail, and securing a better grasp of the language. which he kept but has never been identified, struck him There are three Polynesian sails at the British Museum. as “as neat a piece of work” as he had ever seen [12; p. The Tahitian sail was kept in storage along with a second 120 (vol. 1)]. One of the authors (TH) has investigated sail from elsewhere in Polynesia (Oc1999,Q.140), possibly the possibility that it could be another Polynesian sail at from the Hawaiian or Marquesas Islands. The latter sail the British Museum (Oc1999,Q.140), but for a variety of measures 5.1 × 3.6 m and features small geometric designs reasons this seems unlikely. A chief (ari’i) of the Hitia‘a of dark leaf strips within the pale pandanus weave. This district on the eastern side of Tahiti gave a long, woven smaller sail is scheduled to be conserved during 2009, sail to the second European captain to reach the island and the authors intend to publish any findings from their (Louis de Bougainville), who arrived on the Boudeuse a examination and treatment of this object in due course. few months after Samuel Wallis’s initial visit in 1767 [16].5 A third sail, from New Zealand (Oc,NZ.147.7), which The sail would presumably have been taken back to Paris, is trimmed with black feathers, has an elongated, inverted along with Ahutoru, a high-born young man of the Hitia‘a triangular form, 4.4 m long and 1.9 m at its widest end. district and the first Pacific islander to visit Europe. These three are the only known surviving examples of The objects collected and their collection history show ancient Polynesian sails and, in addition, the British that canoes were only really of interest to the explorers Museum appears to be the only institution that holds themselves (rather than other members of their crew) elements from the material culture related to canoes and only the first explorers were able and eager to study collected at the time they were made and used. British them. Indeed, the changes initiated by these contacts voyagers collected Polynesian material relating to fields radically and irrevocably altered Polynesian traditions other than navigation, and the British Museum holds one and crafts. Captain George Vancouver noted that as early of the richest Polynesian collections in the world. as 1793 Hawaii’s great chiefs followed the great chief There is a canoe (Oc1771,0531.1), which is nearly intact Kamehameha’s example and rigged their canoes with (the beam is missing and possibly part of the stern) from western sails [17]. This was also the case in other parts Nukutavake Island in the Tuamotu Archipelago. This was of Polynesia and particularly on those islands that had a collected by Captain Samuel Wallis in 1767 and was prob- privileged contact with Europeans. ably given to the Admiralty of the Royal Navy, which in turn donated it to the British Museum in 1771 [19]. There are also, from Tahiti, examples of the carved posts that Sails and canoes at the British Museum decorated the stern and prow of many canoes, showing anthropomorphic ancestor figures (ti’i) standing back There are no extant records of the British Museum sail’s to back, for example British Museum Oc,Tah.60. A large arrival or early history at the Museum. Two sails made steering paddle (Oc,Tah.87) and a bailer (Oc,Tah.6) that of “coarse mats” were listed in an 1842 Synopsis of the were almost certainly collected during James Cook’s visits Museum as part of the long-term display in the popular are other highlights of the Museum’s Polynesian maritime ‘South Seas Room’ [18]. This room acted primarily as a collection. These objects provide fundamental informa- showcase for material from Cook’s voyages. There is insuf- tion, and having been collected during the early years of ficient evidence to confirm which sails these were, but the contact with Europeans, they document the changes that Tahitian sail is likely to have been collected very early; it occurred as canoe-builders who were used to working

9 TARA HIQUILY, JENNY NEWELL, MONIQUE PULLAN, NICOLE RODE AND ARIANNA BERNUCCI with tools of stone, bone and shell gained access to new AUTHORS tools and materials with which to experiment. Tara Hiquily ([email protected]) is curator at the Musée de Tahiti, and a specialist in the history and technology of Poly- nesian canoes. Jenny Newell ([email protected]) is a research fellow at the National Museum of Australia and was formerly a curator in CONCLUSIONS the Department of Africa, Oceania and the Americas at the British Museum. Monique Pullan ([email protected]), The ban enforced by the French colonial administration on Nicole Rode ([email protected]) and Arianna Bernucci ([email protected]) are conservators in the Depart- inter-island travel brought the end of sailing canoes from the ment of Conservation and Scientific Research at the British Museum. 1840s and women stopped weaving sails as small, paddled canoes met the needs for fishing and transport around the coast. Today, Society Islanders sail western-style boats and paddle fibreglass canoes when fishing, travelling around REFERENCES their coastlines, and racing between the islands in annual canoe competitions. In the cultural renaissance under way in 1. Florian, M.-L.E., Kronkright, D.P. and Norton, R.E., The conser- the islands, there is a growing interest in rediscovering and vation of artifacts made from plant materials, Getty Conservation reconstructing early voyaging canoe technologies. The sails Institute, Marina del Rey (1990) 267 and 287–292. in the British Museum are precious repositories of cultural 2. Wills, B., ‘Toning paper as a repair material: its application to three- knowledge of ongoing relevance in Polynesia today. dimensional organic objects’, The Paper Conservator 26 (2002) 27–36. While the conservation of this sail aimed primarily to 3. Britton, N.C., ‘Basket cases: two upholstery treatments composed ensure the long-term preservation of this unique object, in- of plant materials’, in The Textile Specialty Group Postprints – 1994, depth technical examination, extensive documentation and ed. C. McLean, American Institute for Conservation, Washington interpretation of the sail between British Museum curators DC (1995) 27–38. 4. Haddon, A.C. and Hornell, J., Canoes of Oceania, Bernice P. Bishop and conservators and a Tahitian curator was an important Museum, Honolulu (1991). part of the conservation project. This project has allowed 5. Ellis, W., A la recherche de la Polynésie d’autrefois, Société des océa- a variety of interested parties, including Pacific communi- nistes, Paris (1972). ties physically distant from the UK (both English and non- 6. Neyret, J., Pirogues oceaniennes, vol. 2, Association des Musées de la Marine, Paris (1974). English speakers) access to the sail without compromising 7. Rutter, O. (ed.), The journal of James Morrison, boatswain’s mate of its long-term preservation. the Bounty, Golden Cockerel Press, London (1935). 8. Hiquily, T., Glaunec, M. and Millaud, H. (eds), Va’a: la pirogue Polynésien, Au Vent des Iles, Pirae, Tahiti (2008). 9. Haddon, A.C. and Hornell, J., The canoes of Oceania, 3 vols, Bishop Museum Press, Honolulu (1936–1938): reprinted 1991. ACKNOWLEDGEMENTS 10. Howe, K.R. (ed.), Vaka Moana, voyages of the ancestors: the discovery and settlement of the Pacific, University of Hawaii Press, Honolulu The authors would like to thank: curators Dorota Starzecka and Jill (2007). Hasell, who recognized the significance of the sail (Jill Hasell also kindly 11. Brigham, W.T. and Stokes, J.F.G., Mat and basket weaving of the commented on an earlier draft of this manuscript); Sara Pimpaneau, ancient Hawaiians described and compared with the basketry of the Montreal, for her excellent work on TH’s French text; Sherry Doyal, other Pacific Islanders, Bishop Museum Press, Honolulu (1906). head of organics conservation; and the conservators in the organics 12. Hawkesworth, J., An account of the voyages undertaken by the order conservation section who assisted with the conservation of the sail, of His Present Majesty for making discoveries in the southern hemi- particularly Jane Hamill and Cajsa Hallgren. sphere, vols 1 and 2, Strahan and Cadell, London (1773). 13. Thomas, N., Discoveries: the voyages of Captain Cook, Allen Lane/ Penguin Books, London (2003) 345. 14. Salmond, A., ‘Two worlds’, in Vaka Moana, voyages of the ancestors: the discovery and settlement of the Pacific, ed. K.R. Howe, University MATERIALS AND SUPPLIERS of Hawaii Press, Honolulu (2007) 246–269. 15. Beaglehole, J.C. (ed.), The journals of Captain James Cook: journal of • Vulcanised latex rubber sponge (‘smoke sponge’), Melinex® the voyage of the Endeavour 1769–1771, vol. 1, Cambridge Univer- (125 μm), Tyvek® and Gore-Tex®: Preservation Equipment Ltd., sity Press and the Hakluyt Society, Cambridge (1955) 129–132 and Vinces Road, Diss, Norfolk IP22 4HQ, UK. Sympantex® (also 153–154. available through Preservation Equipment Ltd.) can be used as a 16. Salmond, A., Aphrodite’s island: the European discovery of Tahiti, cheaper alternative to Gore-Tex®. University of California Press, Berkeley (forthcoming). • Tengujo mulberry paper: Shepherds Bookbinders Ltd (formerly 17. Lamb, W.K. (ed.), A voyage of discovery to the North Pacific Ocean Faulkiner Fine Papers), 76 Southampton Row, London, WC1B and round the world, 1791–1795 [by George Vancouver], Hakluyt 4AR, UK. Society, London (1984). • Lascaux Acrylic Adhesive 498 HV: AP Fitzpatrick, 142 Cambridge 18. Synopsis of the contents of the British Museum, Trustees of the Heath Road, London E1 5QJ, UK. British Museum, London (1842). • Liquitex® acrylic paints: Cornelissen & Sons, 105 Great Russell 19. Hooper, S., Pacific encounters: art and divinity in Polynesia, British Street, London, WC1B 3RY, UK. Museum Press, London (2006) 121.

10 CONSERVING AND RESEARCHING A RARE TAHITIAN CANOE SAIL

NOTES 3. A presentation by J. Bracko entitled ‘Ten Tips for Tyvek’ given at a meeting of the Textile Specialty Group (TSG) of the American 1. Preliminary identifications of the materials in the sail were made Institute for Conservation in Richmond, Virginia in 1990 is cited by visual examination by one of the authors (TH). The botanical in reference [3]. species present were confirmed as Pandanus tectorius, Hibiscus 4. www.britishmuseum.org/research/search_the_collection_ tiliaceus and Cocos nucifera by Caroline Cartwright. database.aspx (accessed 31 March 2009). Boudeuse 2. An article entitled ‘British Museum “discovers” 2 pre-European 5. The journal of Nicholas Duclos-Guyot (of the ), held in Tahitian canoe sails’ appeared in the Tahiti Presse in 2008. Available the Musée National d’Histoire Naturelle, Paris, Ms 2214, Book 1, at http://outriggersailingcanoes.blogspot.com/2008/03/ancient- f. 155, is quoted in [17]. sail-found.html (accessed 22 June 2009).

11 Limoges painted enamels: evidence for specialist copper-smithing workshops Susan La Niece, Stefan Röhrs, Dora Thornton and Antony Simpson

Summary French enamellers active in Limoges during the late fifteenth to the early seventeenth century were noted for their fine painted scenes taken from classical mythology and Christian traditions. The forms made in the Limoges workshops included plaques, plates of various sizes, ewers and ewer stands, salt cellars, candlesticks and footed bowls, all of which were intended to be decorative rather than functional. Instead of the more obvious painted enamel surfaces, this study examines the metalwork of these vessels. The metal, entirely hidden beneath the enamel, is generally of sheet copper. While the study of damaged objects reveals constructional features, X-radiography of unaltered enamels, complemented by examination using a microscope and boroscope, has made it possible to understand the construction of the more complex shapes. The methods used to join the components are quite unlike those seen in sheet metalwork that was not intended for enamelling, and are partly explained by the need to avoid solder, which could not survive the temperatures of the multiple enamelling stages. The crudeness of the metalwork is in stark contrast to the quality of the enamelling and some very unusual and ingenious means were employed to conceal the mechanical joins in hollow feet. It is likely that the difficulties of the enamelling process led to many failures and rejects, making it uneconomical to invest time and effort in making the metal forms, although one common feature is that the metal was consistently kept as thin as practicable to minimize the adverse effects of differential expansion and contraction during firing and cooling. These observations lead to the conclusion that there were specialist metal workshops that were mass-producing copper forms specifically for enamelling.

INTRODUCTION religious subjects that were probably intended for private devotion, good examples being two plaques (1922,0707.1 This study developed from a collaboration between the and 1913,1220.28) in the British Museum, signed by British Museum and the Wallace Collection. The impor- Léonard Limosin and dated 1536, that show scenes from tant collection of Limoges painted enamels at the Wallace the life of St Anthony Abbott [2; p. 40 and Plates 16, 17 and has recently been catalogued by Higgott [1], and scien- 39]. Both plaques also bear the arms of Jean de Langeac, tific analysis and X-radiography of some objects from that a powerful figure at the French court who had served as collection were carried out by two of the authors (SLaN ambassador to Francis I and as councillor to Henry II of and SR) at the Department of Conservation and Scien- France; he was also Bishop of Limoges from 1533 to 1541. tific Research at the British Museum.1 The results of these It is de Langeac who is credited with introducing this new scientific studies raised some interesting questions about art form to the French court and for helping to promote the metal substrate to the enamel and encouraged further Léonard Limosin to the role of ‘peintre émailleur et valet work on objects selected from the extensive collection of de chambre du roi’ in 1548 [2; p. 16]. Surviving pieces these enamels at the British Museum. and contemporary inventories demonstrate that Limosin’s It was in Limoges in central France that the traditional works, and those of other enamellers, were to be found in craft of enamelling on copper entered a new dimension royal chapels and palaces from the mid-sixteenth century, from the late fifteenth century. Instead of being engraved not just in France but in England, at the court of Henry or channelled out to take the enamel, the whole copper VIII [3; pp. 29–30, 4]. surface was carefully treated and painted like an artist’s Among other technical advances, two changes occurred canvas. The first works were small plaques painted with in the 1530s. The first was the introduction of the sophisti-

13 SUSAN LA NIECE, STEFAN RÖHRS, DORA THORNTON AND ANTONY SIMPSON cated grisaille technique, with white painting layered on a auctions such as the Fountaine Sale of 1884 (see the ewer dark ground. The second was the production of more elab- analysed below), it comprises mainly two collections [12]. orate copper forms, including ewers, footed bowls with The first and most important is that of Baron Ferdinand covers, candlesticks, table fountains and salts of various Rothschild, known as the Waddesdon Bequest, which shapes. These were made from copper elements joined was left to the British Museum in 1898. The second together in the manner discussed in this contribution. major collection is that of the Reverend A.H.S. Barwell, The surfaces would be unified through the application of bequeathed to the Museum in 1913. Neither collection has a base enamel layer, usually mulberry-coloured or blue, been catalogued in full, although records for each piece, before being painted and gilded to create a rich effect that along with all available images, can found in the Collection completely concealed the copper structure beneath. Database on the British Museum website.2 Painted enamel enjoyed its greatest prestige in the mid- The techniques and materials used to produce the enam- to late-sixteenth century. Large workshops developed elled decoration have attracted the interest of researchers to cope with increasing demand in France and beyond and analysis has already begun to establish the recipes used for this new and innovative technique. The enamelling by the enamellers [13–17]. Less attention has been paid to industry was important to the export trade of Limoges. the metal substrate onto which the enamel was applied. Family names such as Pénicaud, Limosin and Reymond Freestone and Lang examined a ewer in the collections are found repeatedly in documents in the Limoges at Waddesdon Manor using X-radiography, noting that archives recording the activities of craftsmen in related the metal body was made in several sections joined by fields, such as goldsmiths’ work, painting and illumination wires [18]. Recently, Speel carried out a more extensive or engraving; for example, Léonard Limosin is known to technical study of Limoges painted enamels of the Grünen have worked as a painter and engraver as well as an enam- Gewölbe (Green Vault) in Dresden [19]. She described the eller [2; pp. 22–25], and Pierre Reymond as an illuminator construction of a slightly unusual ewer that was under- and designer of stained glass and liturgical silver [3; p. 82]. going restoration; here, the use of wire ties was combined Many of their enamelled products are signed and dated, with tabs inserted through slots, particularly to attach the while other pieces can be attributed to particular enamel- foot. In addition, an examination of damaged objects by lers or workshops on stylistic grounds alone. In addition, Beillard revealed several techniques that had been used to it is often possible to identify the woodcuts and engravings assemble enamelled dishes and cups and drew attention to that served as source material for the narratives and orna- changes in these methods between the earlier enamels and mental designs on these enamels [5; pp. 24–32]. those of the seventeenth century.3 Following the French Revolution there was a nostalgic revival of interest in Medieval and then Renaissance French art, and painted enamels were avidly collected, particularly in Paris [6; pp. 9–12, 7, 8]. Painted enamels RADIOGRAPHY AND ITS INTERPRETATION were highly placed in the aesthetic hierarchy of decorative arts and fetched high prices on the art market [9]. X-radiography was carried out at exposures ranging from Plaques were put into modern frames, damaged sections 10 mA minutes at 75 kV to 40 mA minutes at 90 kV, of complex forms were repaired, covered over or replaced depending on the size and density of the object. The images with modern elements to meet demand and pieces were were recorded on Agfa D4 or D7 radiographic film and even faked. The repairer Simon-Émerique Pierrat was a scanned digitally at a resolution of 50 μm. The scanned known specialist in this area, employing the skills of enam- images were processed in Adobe Photoshop to enhance ellers in the Sèvres porcelain manufactories until he was the images to a publication standard, but without adding unmasked as a faker in a famous court case involving the or subtracting any features seen on the films. Dense areas Rothschilds in 1859 [10]. His pupil Alfred André (1839– appear pale in the X-radiographic images; the lighter the 1919) went on to handle and repair most of the impor- shade the more dense the feature. The factors contrib- tant pieces on the art market and in private collections. uting to the density are thickness of the materials and André is known to have worked on enamels belonging to the nature of the materials themselves. For example lead- Baron Ferdinand Rothschild that are now in the British and tin-containing white enamels appear pale on these Museum; his technique of replacing whole damaged areas images, but although gold absorbs X-rays strongly, it was of old enamel with new, fired plaques has been studied by applied so thinly to the enamels that it is not visible on the Tait and Freestone [11]. A casket set in the Waddesdon X-radiographs. Bequest with enamels by Suzanne Court demonstrates To understand the X-radiographic images it is neces- André’s method and his alterations can be dated to the sary to allow for the superposition of the images from mid-1880s [11]. the enamelling on the front and back of the object and, The British Museum’s collection of painted enamels of course, for the features of the metal base-plate that was formed by Augustus Wollaston Franks from the also appear on the image. Often a shadow image of the 1850s onwards. Apart from pieces collected by Franks painting, or the ‘bubbly’ texture of the enamel, can also be himself, or acquired for the British Museum at major seen in the X-radiograph.

14 LIMOGES PAINTED ENAMELS: EVIDENCE FOR SPECIALIST COPPER-SMITHING WORKSHOPS

figure 1. Painted Limoges enamel salt cellar decorated with the follies of wise men; attributed to the enameller Pierre Reymond: height 7.1 cm. Donated by A.W. Franks in 1888

Salt (1888,0705.1)

This hexagonal salt cellar is enamelled in grisaille with touches of green, mauve and blue and shows the follies of wise men with their names inscribed and details in gilding, Figure 1. It is dated 1542 and, although unsigned, is attributed to Pierre Reymond. The X-radiograph in Figure 2 shows that the metal body of this salt is constructed from three pieces – the top and bottom were cut to shape from flat sheet metal and a circular depression hammered in the centre of both the top and bottom. The sides were formed from a single sheet, which was pierced with small holes where its ends overlap at the join, and thin strips of metal threaded through to ‘stitch’ it together. The top and bottom of the salt were secured to the sides with thin wires (that appear white in the X-radiograph) threaded through holes in the metal and tied off on the outside. The final enamelling hides the wires but slightly raised areas in the enamelled surface reveal their positions. The mottled, bubbly appearance in the X- radiographic images can be attributed to the enamel or counter enamel rather than to the metal.

Ewer (1885,0420.17)

This mid-sixteenth century ewer is enamelled in black, white and blue with details in gilding, Figure 3. The grisaille figure 2. X-radiographic images of the salt cellar: (a) scenes illustrate the theme of Charity, complemented by top view and; (b) side view showing the strip metal texts from chapter 58 in the Vulgate version of the Book ‘stitches’ running down the side (marked with arrows) and the thin wire loops (white) threaded through of Isaiah. It is signed ‘PR’ in gold on the handle and lip for holes in the top and bottom to hold them in place Pierre Reymond. Unidentified arms enamelled on the lip

15 SUSAN LA NIECE, STEFAN RÖHRS, DORA THORNTON AND ANTONY SIMPSON

of the ewer may be those of a religious confraternity rather than an individual patron. This ewer was in the Fountaine Collection at Narford Hall in Norfolk, where it was listed in the 1835 inventory, and is incised with a Fountaine collection mark ‘af 10’ under the foot. It was sold to the British Museum at Christie’s on 18 June 1884 (lot 285) [20]. The X-radiograph of this ewer reveals a complex construction underneath the enamel, with the metal form composed of six main components, Figure 4. The body has three components: the neck, shoulder and bowl. A hollow D-sectioned handle, made of two strips folded together along their length is attached to the top of the neck and to the shoulder. The foot is hollow and flaring and, like so many similar ewers, there is some damage and restoration to the enamel where it joins the body. However, the X- radiograph shows the constructional features to be relatively well preserved. This ewer, like other Limoges pieces with narrow hollow bases (see also the footed bowl below), has an enamelled disc inserted part-way up the foot, presumably to conceal an unattractive mechanical join. The X- radiograph in Figure 5 shows a mushroom-shaped disc at the bottom of the ewer, although this was not visible on examination of the cavity with an Olympus Maj-522 boroscope, as it is apparently well covered by the counter-enamel layer on the interior. The boroscopic examination of this area revealed no evidence of damage, inferring that this mushroom-shaped disc is part of the original construc- figure 3. Ewer with scenes from Isaiah illustrating the theme tion. How the disc functions is not, however, clear. There of Charity; attributed to the enameller Pierre Reymond: height from base to top of handle 32 cm are no signs of tabs of the type seen on the foot of the ewer

figure 4. X-radiographic image of the ewer and an exploded diagram of the metal construction based on a speculative interpretation of the X-radiographs

16 LIMOGES PAINTED ENAMELS: EVIDENCE FOR SPECIALIST COPPER-SMITHING WORKSHOPS

figure 5. Detail of the X-radiographic image of the foot of the ewer showing the two discs with metal strips between them and what may be fine wires (marked with an arrow)

figure 6. Detail of the X-radiographic image of the join between the top and bottom sections of the ewer. The overlap where the two sections fit together appears as the pale band across the image. The wire (white) is threaded through the pair of holes in the upper section and re-emerges from the pair of holes in the lower section, where the ends of the wire were twisted together. All this is now concealed on the exterior by enamel examined by Speel, although there are fine white lines on the image that may indicate the presence of strands of wire figure 7. Images from the boroscopic examination of the threaded between the foot and bowl of the ewer. The mush- counter-enamelled interior of the ewer showing details along room-shaped disc has a projection from its centre that seems the join between the shoulder and lower body. In each case the dark horizontal feature is the leakage of the exterior enamel to protrude through the bottom of the ewer and connect in along the join: (a) the wire loop can be seen emerging into the some way to the curved strip of metal apparently attached cavity through two holes in the shoulder section of the ewer, and at one end to the disc in the foot. A ewer from the Wallace passing back through the top edge of the lower part of the body; Collection (IIIF 265), also attributed to the enameller Pierre (b) close-up of the wire loop, showing the exterior enamelling seeping in through the top holes; and (c) a wire loop, arrowed Reymond, has an enamelled disc in the foot, with two curved bottom left, and the wire joining the bottom of the handle to strips of metal on the back, but the bottom of the Wallace the ewer shoulder, arrowed top right. The counter-enamelling ewer has been repaired, obscuring the constructional features almost covers this join

17 SUSAN LA NIECE, STEFAN RÖHRS, DORA THORNTON AND ANTONY SIMPSON that appear in the X-radiographic image. Further examina- Collection. The X-radiographs of this footed bowl and other tion of undamaged ewers is needed to give more information similar objects suggest the following sequence was followed about the original structure of such joins. for assembling the foot and the bowl (see Figure 9): The joins between the other components are easier to understand. An X-radiographic detail of the join line between 1. A cylinder, to fit inside the foot, was made by bending the shoulder and the lower half of the ewer body shows the sheet metal and joining it with ‘stitches’ of thin strips of wire ties threaded through holes in the copper, Figure 6. metal down the side. The top edge of the cylinder was Examination of the interior of this ewer with a boroscope fed cut to leave four protruding tabs. These tabs at the top through the narrow neck (Figure 7) confirmed that the wires of the cylinder were pushed through four slots at the were threaded into the cavity through holes in the shoulder centre of the metal bowl and folded flat. and back to the outside through holes in the lower section of 2. Holes were made through the metal foot and the inner the ewer. They were twisted into a knot on the outside and cylinder, to be fully aligned with each other once the the surplus wire clipped off.4 The handle was also attached by foot was in position. the same means, but with a double wire to attach the bottom 3. The bowl was painted and fired, perhaps using the of the handle and two single wires to attach it to the top of cylinder as a support in the kiln. The foot and disc were the neck. painted and fired separately. 4. With the bowl inverted, the foot was placed in position over the cylinder with the holes aligned. Footed bowl or tazza (WB 36) 5. The enamelled disc was inserted into the bottom of the foot to conceal the interior construction. The purpose This mid-sixteenth-century footed bowl (Waddesdon Bequest of the loop on the back of the disc is enigmatic but as 36) is painted in black, white and salmon pink with details in it seems to be a feature of all such discs and has no gilding, Figure 8.The grisaille enamels show scenes from the obvious structural function, it may have been to assist story of Jacob including his dream and ladder to heaven. This in assembly. It is suggested that a fine wire may have tazza is inscribed ‘I.C.’ and attributed to Jean de Court. been threaded through the hole in one side of the foot It can be seen from the X-radiographic image (Figure and cylinder, through the loop on the disc and finally 9) that the hollow flaring foot does not quite touch the back through the hole in the other side of the cylinder bottom of the bowl. The connection between the two is via and foot. By pulling both ends of the wire, the disc a cylinder of metal concealed inside the foot and locked in could have been drawn up into the foot, sealing the place by a metal rod that was pushed through both the foot opening and concealing the unattractive mechanical and the internal cylinder, Figure 10. The two ends of this join between bowl and foot; rod are visible where they emerge from the foot and this 6. The whole assembly was secured by pushing the rod feature has been noted on all bowls with a narrow foot that through the holes in the foot and cylinder and a final have been examined in the British Museum and the Wallace firing of the enamel bonded the disc in place.

figure 8. Footed bowl (tazza) with scenes from the story of Jacob; attributed to the enameller Jean de Court: bowl diameter 25.1 cm. Waddesdon Bequest 36

18 LIMOGES PAINTED ENAMELS: EVIDENCE FOR SPECIALIST COPPER-SMITHING WORKSHOPS

figure 9. X-radiographic image of the footed bowl (note that the hollow foot does not quite touch the bottom of the bowl) and an exploded diagram of the metal construction as interpreted from the X- radiographs: ‘A’ is the enamelled disc with loop; ‘B’ the metal cylinder with stitched seam; and ‘C’ the bowl pierced by four slots to take the four tabs on the top of the metal cylinder

figure 10. Detail of the X-radiographic image in Figure 9 showing the foot of the bowl. The ‘stitched’ join of the internal cylinder is marked with an arrow. The metal rod is pushed through both the cylinder and the outer foot, locking the construction in place, but does not engage with the loop on the back of the disc set inside the foot

19 SUSAN LA NIECE, STEFAN RÖHRS, DORA THORNTON AND ANTONY SIMPSON

This sequence is speculative, particularly the means of fitting to Limoges via Tucher’s office in Lyon to be decorated by the disc. On the X-radiographs there is nothing visible Pierre Reymond in his workshop in Limoges, before being attached to the loop on the back of the disc and it is not in sent back to Nuremberg for further embellishment in contact with the rod or the base of the bowl. There may be silver by Jamnitzer [24]. The correspondence from 1561 a material that is transparent to X-rays, such as thread, still between Leonardt Tucher and the Lyon office suggests that inside the foot; alternatively, whatever was used may not the commission was not without its difficulties [7, 25, 26]. have withstood the final firing of the enamel. This proposed The enamellers refused to work with the copper forms as scenario would account for the otherwise unsupported disc they were too thick to be enamelled and suggested that staying in place and also explains why so many of these they should thin the dishes by beating. But this was not discs have a loop or similar feature on the back. A wider possible in the case of the ewer, which it would not have study of more such bowls may help to clarify this point. been possible to thin, since the parts would then no longer fit together.5 The story of this commission suggests that Tucher had Nuremberg forms and fashions in mind for this special commission, in line with the latest goldsmiths’ THE EVIDENCE FOR MANUFACTURE OF THE designs and craftsmanship. Those pieces from the Tucher COPPER FORMS set that survive, which are now in Nuremberg and Munich, are indeed distinctively different from the rest of Limoges Recent studies of the post-mortem inventories of enamel- production, primarily due to the forms of the copper blanks lers in Limoges workshops of the sixteenth and seventeenth for the ewers. The significance of the thickness, or rather the centuries show that they did not own tools for working thinness, of the metal required for enamelling is of interest copper, but mention instead copper blanks ready to cover here. In Speel’s study of the Dresden enamels [19; p. 156], with enamel. One inventory of 1675 lists ‘various pieces the thickness of the metal was on average about 0.7 mm, of red copper of various forms ready to be made up and with the edges often even thinner, which was also found to covered in enamel’ (“diverses pièces de cuivre rouge de be the case for the salt and ewer examined here. Keeping the diverse façon à mettre en oeuvre et couvrir d’émail”) [21]. metal as thin as practicable helps to minimize the problems Furthermore, although in the Middle Ages the professions caused by differential expansion and contraction of metal of enameller and fine metalworker seem to be indistinguish- and enamel during firing and cooling. able, by the end of the sixteenth century named enamellers The assembly methods seen on the Dresden ewer have are not the same as named fine metalworkers, although they clear similarities to those for the British Museum and often belonged to the same family [21]. It is therefore likely Wallace Collection ewers, but there are also differences: that each workshop would have had its own, probably local, double twisted wires were used on the Dresden ewer, supplier of blanks. Much the same differentiation between while single wires were found on the British Museum potters and painters or decorators is found in tin-glazed ewer; and the feet of both the Dresden ewer and British ceramic workshops in Nevers in the late sixteenth and early Museum tazza were attached by tabs, while the foot of the seventeenth century [12; p. 551, 22]. British Museum ewer has no tabs. It may be that different It is not known where the copper came from, but it workshops favoured different methods or, as suggested by had to be pure copper, cuivre de rosette, to be suitable for Beillard, the methods developed over time. enamelling. Earlier Limoges workshops are thought to have used French copper, whereas it has been suggested that the sixteenth-century workshops used Spanish New World copper traded along the pilgrim route to Santiago CONCLUSIONS de Compostela, which runs close by Limoges [3; p. 18, 23]. Alternative sources of supply were England, via the port The metal forms for these enamels have two main charac- of La Rochelle, or Germany, via Lyon [21; p. 164]. What teristics. First that the metal is thin enough to minimize is striking, as this technical analysis shows, is the relative the differences in thermal expansion between copper and crudeness of the workmanship of the copper forms in enamel. The Tucher correspondence confirms that this was contrast to the skill of the painted enamel decoration that essential to the enamelling process and that the conventional covered them. An exception to this rule is illuminating. The forms made in a leading goldsmith’s workshop were unsuit- leading Limoges enameller of the mid-sixteenth century, able. The second rule is that all the joins must be purely Pierre Reymond (two of whose works are analysed here), mechanical. This can be explained by the need to avoid made a group of cups, a ewer and footed dishes for the solder, which would melt at the temperatures required for Nuremberg patrician and merchant Leonardt Tucher, all of the multiple enamelling stages. However, even taking into which were decorated with his arms impaling those of two account these two factors, the crudeness of the metalwork successive wives. The ewer is unusual in shape and differs is in such stark contrast to the quality of the enamelling that from the conventional Limoges forms, and this is because it requires a little more explanation. the leading Nuremberg goldsmith, Wenzel Jamnitzer, was Thin sheet metal objects with mechanical joins are commissioned to make the copper forms. These were sent known from the earliest times and are by no means always

20 LIMOGES PAINTED ENAMELS: EVIDENCE FOR SPECIALIST COPPER-SMITHING WORKSHOPS crude. It would seem that the methods of constructing the REFERENCES metal forms seen here are very specific to enamelled work. The metal components needed to be tightly fixed together to 1. Higgott, S., The Wallace Collection catalogue of glass and Limoges painted enamels avoid movement during the enamelling process and the use (forthcoming). 2. Baratte, S., Léonard Limosin au musée du Louvre, Réunion des of wire, metal strip and tabs to hold them together appears musées nationaux, Paris (1993). to have been successful in this respect, although the finished 3. Caroselli, S.L., The painted enamels of Limoges, Los Angeles objects are still vulnerable to the stresses of handling, as County Museum of Art, Los Angeles (1993). 4. Tait, H., ‘Limoges painted enamels: changes around 1530’, in can be seen from the number that are now damaged and Neue Forschungen zum Maleremail aus Limoges – New research restored. It is likely that the difficulties of the enamelling on Limoges painted enamel, ed. I. Müsch and H. Stege, Herzog process led to many failures and rejects, so that it was not Anton Ulrich-Museum, Brunswick (2004) 11–15. worth investing time or material in making the metal bases 5. Weinhold, U. (ed.), Maleremail aus Limoges im Grünen Gewölbe, when the enamel would later be applied thickly enough to Deutscher Kunstverlag, Berlin (2008). 6. Baratte, S., Les émaux peints de Limoges, Réunion des musées mask the uneven surface of the joins. An example can be nationaux, Paris (2000). seen from the pair of salts in the Wallace Collection (IIIM 7. Netzer, S., Maleremails aus Limoges, G + H Verlag, Berlin (1999) 260 and 261), where the sides of one of the hexagonal salts 21–35. exhibit a stitched seam similar to that on the British Museum 8. Thornton, D., ‘The Waddesdon Bequest as a neo-Kunstkammer of the nineteenth century’, Silver Studies 23 (2008) 57–68. salt discussed above. The second salt of the pair has not just 9. Thornton, D., ‘Painted enamels of Limoges in the Wernher Collec- one, but two stitched seams; although the piece of copper tion’, Apollo (May 2002) 10–16. was too short it was not discarded, but another piece was 10. Eudel, P., Le truquage, E. Dentu, Paris (1884) 149–154. stitched on to avoid wastage [1]. It is already established 11. Tait, H. and Freestone, I., ‘Painted enamel patches : a 19th century virtuoso restorer’s technique’, in Neue Forschungen zum Malere- that at this period the metalworkers supplying the Limoges mail aus Limoges – New research on Limoges painted enamel, ed. industry constituted a separate profession from the enamel- I. Müsch and H. Stege, Herzog Anton Ulrich-Museum, Brunswick lers. The observations from this study lead to the conclusion (2004) 117–122. Italian Renaissance ceramics: a cata- that these were specialist metal workshops that were mass- 12. Thornton, D. and Wilson, T., logue of the British Museum’s collection, British Museum Press, producing forms with a construction and thinness specifi- London (2009) 14–15. cally suited for enamelling. However, the number of these 13. Biron, I., ‘Study of XVth and XVIth century painted enamels metal workshops and how the distribution of the copper on the basis of scientific analysis: causes of glass deterioration’, Berliner Beiträge zur Archäometrie forms to the enamellers was organized remain unclear. The 16 (1999) 163–174. 14. Röhrs, S. Authentizitätsuntersuchungen an Limousiner Maler- minor differences in joining methods seen between the very emails durch mikro-röntgenfluoreszenzspektrometrische Materi- few objects that have so far been examined in depth may alanalysen, PhD thesis, Technische Universität Berlin (2004): offer means of grouping the metalwork, if not in terms of http://edocs.tu-berlin.de/diss/2003/roehrs_stefan.htm (accessed workshops, at least in terms of date. The examination of 31 March 2009). 15. Biron, I., ‘Study of Limoges painted enamels at the Center for more such enamels may well provide rewarding insights Research and Restoration of the Museum of France’, in Neue Forsc- into workshop practices for the Limoges painted enamel hungen zum Maleremail aus Limoges – New research on Limoges production. painted enamel, ed. I. Müsch and H. Stege, Herzog Anton Ulrich- Museum, Brunswick (2004) 85–99. 16. Röhrs, S. and Stege, H., ‘Dating indicators for authenticity problems of Limoges painted enamels basing on material characterization’, in Neue Forschungen zum Maleremail aus Limoges – New ACKNOWLEDGEMENTS research on Limoges painted enamel, ed. I. Müsch and H. Stege, Herzog Anton Ulrich-Museum, Brunswick (2004) 100–107. 17. Röhrs, S., Biron, I. and Stege, H., ‘About Limoges painted enamels: The authors are grateful to Suzanne Higgott of the Wallace Collec- chronological evolution of the glass chemical composition’, Asso- tion for providing the initial impetus for this research and also for ciation International pour l’histoire du Verre, Annales du 17e her comments and those of the anonymous referee on a draft of this congres (in press). paper. 18. Lang, J. and Middleton, A., Radiography of cultural material, 2nd edn, Elsevier Butterworth-Heinemann, London (2005) 59–61. 19. Speel, E., ‘Die Werkmaterialien und ihre Anwendungstechniken als bestimmende Faktoren für die stilistischen Entwicklungen’, in Maleremail aus Limoges im Grünen Gewölbe, ed. U. Weinhold, AUTHORS Deutscher Kunstverlag, Berlin (2008) 156–157. 20. Moore, A.W. (ed.), Norfolk and the Grand Tour, Norfolk Museums Susan La Niece ([email protected]) and Antony Service, Norwich (1985) catalogue number 32. Simpson ([email protected]) are scientists in 21. Beyssi-Cassan, M., Le metier d’émailleur à Limoges XVIe –XVIIe siècle the Department of Conservation and Scientific Research. Stefan , Presses Universitaires de Limoges et du Limousin, Limoges Röhrs ([email protected]) is a scientist at the Rathgen- (2006) 108 and 113–120. 22. Taburet, M., La faïence de Nevers et le miracle lyonnais au XVIe Forschungslabor of the National Museums in Berlin and was formerly siècle, Editions Sous le Vent, Paris (1981) 62. a scientist at the British Museum. Dora Thornton (dthornton@ 23. Notin, V., Cuivres d’orfèvres, Musée de l’Evêché, Limoges (1996) thebritishmuseum.ac.uk) is a curator in the Department of Prehistory 21–22. and Europe at the British Museum. 24. Verdier, P., The Walters Art Gallery: catalogue of the painted enamels of the Renaissance, Walters Art Gallery, Baltimore (1967) 243–247.

21 SUSAN LA NIECE, STEFAN RÖHRS, DORA THORNTON AND ANTONY SIMPSON

25. Grote, L., Die Tucher, Prestel-Verlag, Munich (1961). metallo’, at the Villa Medici in Rome, 10–11 March 2008 (‘Conser- 26. Hampe, T., ‘Splitter zur Jamnitzerforschung’, in Festschrift für vation contributions in the study of enamelled services’). Georg Habich zum 60 Geburtstag, Munich (1928). 4. Janet Lang interpreted the ‘bubbly’ appearance of the medial join on the ewer from Waddesdon Manor as an indication of the presence of a hard solder. However, the presence of solder seems inherently unlikely and a comparison of the X-radiographic images suggests that the bubbly appearance is attributable solely NOTES to the enamel. 5. Netzer [7; p. 21] cites the letter from Herdegen Tucher in Lyon to 1. Isabelle Biron and Thierry Borel also carried out scientific exami- his father Lienhard (Leonardt) Tucher (after Grote [25], which is in nation and X-radiography on other objects from the Wallace turn based on Hampe [26]): “Was die Schalen und die kupfernen Collection at the Louvre laboratories, see Higgott [1]. Vasen angeht, die Eure Weisheit hierher gesandt, um sie nach 2. www.britishmuseum.org/research/search_the_collection_ Limoges zu schicken, damit [sie] dort geschmolzenes Werk wie sie database.aspx (accessed 31 March 2009). es in Brauch haben, darauf machen – so ist das Kupfer zu dick und 3. Béatrice Beillard has presented her research into the construc- nicht dünn genug geschlagen worden. Sie wollen die vir Schalen tion techniques in as yet unpublished papers given at the confer- dort dünner schlagen und auf ihnen arbeiten. Aber mit der Vase ences Les émaux peints limousins: au cœur des arts décoratifs de la geht es nicht, wenn sie diese dünner schlagen ließen, so würden Renaissance in Limoges, 22–24 September 2004 (‘Les assemblages die Stücke nach Aufbringung der Emaille nicht mehr aufeinander des pièces de forme’) and Conservazione e restauro degli smalti su passen.”

22 Egyptian stelae from Malta Jeremy Young, Marcel Marée, Caroline Cartwright and Andrew Middleton

Summary In 1829, four Egyptian stelae of Twelfth and Eighteenth Dynasty date were found, surprisingly, on Malta. Based on their far-flung findspot, some have suggested that the stelae were locally made by Egyptian colonists who had settled on the island during the second millennium bc. This contribution argues that the stelae offer no basis for such historical reconstructions. Style, content and petrology demonstrate that all four stelae were made in Egypt and that they originally stood in the necropolis of Abydos in Upper Egypt. Microfossils show that these stelae are made of Egyptian limestones, which are of a different geological age to limestones available on Malta. The examination of polished thin sections of samples from the stelae using scanning electron microscopy suggests that the limestones employed were quarried from four geological formations of different ages in the Nile Valley.

INTRODUCTION interest in the stelae was generated by an enquiry from Dr Charles Savona-Ventura, who kindly supplied samples of The old Bighi Royal Naval Hospital on the Grand Harbour limestone encountered on Malta, allowing direct compar- in Valletta, which is now home to the Malta Centre for ison with the limestones used for the stelae [4]. Restoration, is one of Malta’s finest examples of neo- classical architecture. The privately owned villa that has graced the site since the seventeenth century was integrated into the hospital when this was built in the early STYLE AND CONTENT nineteenth century. During the excavations for the foundations of the hospital in 1829, four Egyptian stelae came to All four stelae exhibit styles well documented for stelae light from an undocumented context. They were recovered discovered in Egypt and can be connected with the oeuvres by the Clerk of Works, Mr J.B. Collings, who sent them to of specific sculpture workshops. The British Museum stelae the British Museum in 1836, where they bear the registra- also bear evidence to suggest that each was destined to be tion numbers EA 218, EA 233, EA 287 and EA 299. Since set up in Abydos, the cult centre of the god Osiris. their first publication by Murray [1], it has been suggested at The evidence for both these points is clearest in stela various times, most recently in two independent studies by EA 233, Figure 1. Its principal inscription addresses ‘those Testa [2] and Meza [3; pp. 312–313], that these stelae might living on earth, every wab-priest, every lector-priest, every have been made locally by Egyptians who had supposedly scribe and every ka-servant who may pass by this eternal established a colony on the island. As EA 233 dates to the stela’. Those reading the inscription are told that, if they wish late Twelfth Dynasty, while the other three stelae come from their king to be alive for them, their local gods to praise two stages of the Eighteenth Dynasty, it is thus implied that them and to pass their offices to their eldest children, they the Egyptians established a presence on Malta for almost should recite an offering prayer for the benefit of all those five centuries during the second millennium bc, well before commemorated on the monument. The version of the prayer its colonization by the Phoenicians in the following millen- inscribed on EA 233 invokes the king and ‘Osiris, lord of nium. Here it will be argued, however, that the stelae origi- Abydos’; it mentions no other deities or places. Osiris is also nate from Egypt and were brought to Malta at a much later depicted in the lunette of the stela. His mummiform figure date. Evidence for this resides in their inscriptions and is accompanied by the epithets ‘foremost of the westerners representations, as well as in the limestones from which (i.e. the dead), the great god, lord of Abydos’. Facing him these stelae were manufactured. The authors’ renewed is a figure of the second most important deity of Abydos,

23 JEREMY YOUNG, MARCEL MARÉE, CAROLINE CARTWRIGHT AND ANDREW MIDDLETON the jackal-god Wepwawet. It is important to note that stelae erected outside Egypt proper, be this in Nubia, the desert regions or Asia, have never been found to bear depictions of either deity. In contrast, and not surprisingly, their images feature frequently on stelae placed in Abydos, their principal centre of worship. It is only in the course of the Eight- eenth Dynasty that depictions of these gods – chiefly Osiris – begin to appear on stelae set up at other locations. On EA 233, between the two deities, the living king is also represented – through a cartouche. This contains the throne- name of Amenemhat III, who is said to be ‘beloved’ of both gods; his mention dates the stela to c.1855–1808 bc. Similar half-figurative, half-inscriptional compositions are known from the lunettes of other late Middle Kingdom stelae, but by far the closest parallel occurs on stela Louvre C 6 (Figure 2) [5, 6],1 which was undoubtedly made in the same workshop, if not designed by the same draughtsman. In both cases, Osiris and Wepwawet are positioned directly beside the cartouche, and only on these two stelae do both extend towards it the ankh-sign, symbol of life [7].2 There is also complete agreement as regards the single epithet of the king figure 1. Upper part of stela EA 233 from the Twelfth Dynasty, (‘the great god’) and those of the gods.3 The king involved from the reign of Amenemhat III (c.1855–1808 bc) is also the same, and the individual words in the lunette inscriptions are identically positioned. The only major difference is that on the Louvre stela, the outer corners of the lunette still offered space for naming, highly unusually, the sculptor who carved that piece. There is no documented provenance for the Louvre stela but, in common with the British Museum, most of the early collection of stelae in Paris was undoubtedly found in Abydos. The designs of the main panels of the two stelae are very different, but both are 26 cm wide, and while EA 233 has lost its lower part, it may well have been as tall and elongated as the Louvre piece. While the principal owner of EA 233 was a coppersmith, that of C 6 was a government official and accountant, but the latter also mentions a remarkable number of goldsmiths and an overseer of craftsmen. Thus, both pieces were not only commissioned at the same time and place, but name people from the same professional sphere. All in all, it is clear that EA 233 was made and set up in Egypt. As if to reinforce that point, its prayer states that among the offerings its owners seek is ‘that which the Nile produces’, i.e. the crops from Egypt’s annually flooded fields. Little hope of that on Malta! The stela need not have been made where it was dedicated, having perhaps been produced near the capital of Lisht, but there cannot be any doubt that the necropolis of Abydos was its intended eternal environment. Stelae EA 218 and EA 299 (Figures 3 and 4) are both stylistically datable to the early Eighteenth Dynasty, c.1500 bc, and both are from a single and highly produc- tive workshop. The date is amply demonstrated, not only by palaeographic and orthographic features of the inscriptions, but also by the pictorial scenes, the latter carved in raised relief (including the symbolic eyes and shen-ring at the top). As is typical of stelae produced at this time, the figure 2. Stela Louvre C 6 from the Twelfth Dynasty, from the principal owners are depicted seated on chairs with high reign of Amenemhat III (c.1855–1808 bc). Image: Courtesy of backs curved at the top and supported by stiles [8].4 On the Musée du Louvre

24 EGYPTIAN STELAE FROM MALTA

figure 4. Stela EA 299 from the early Eighteenth Dynasty, c.1500 bc. After Murray, M.A., ‘Egyptian objects found in Malta’, Ancient Egypt (1928) Figure 2 (p. 46); the stela has since suffered from salt figure 3. Stela EA 218 from the early Eighteenth Dynasty, c.1500 bc efflorescence

stela EA 218, the woman to the left sniffs a lotus with epigraphy of the inscription is wholly in keeping with the an oddly convoluted stem that is often encountered in suggested date and provenance of the stela. Again, Osiris early Eighteenth Dynasty representations. The woman on is the only god named in the offering formula (with the EA 299 pours a libation over an unusually minute table epithet ‘foremost of the westerners’). In conclusion, this bedecked with elongated offering loaves, the latter reduced stela can hardly have been erected other than in Abydos. to a single block. Closely matching libation scenes with Based on their style and content, it is there that all four similarly tiny tables appear on stelae that seem to be of stelae recovered on Malta must once have stood. the same artistic origin, perhaps even by the same hand, and those whose provenance is recorded have been found in Abydos [9].5 On both EA 218 and EA 299, the offering formula invokes ‘Osiris, ruler of eternity’. Mention of the Abydene god is not in itself conclusive, but again no other deity is named. More importantly, numerous stelae that are known or believed to have been found in Abydos so closely resemble EA 218 and 299 in style and execution that both were undoubtedly also found at that site – before they were taken to Malta. Even in its present fragmentary state, it is clear that the same can be said for EA 287, Figure 5. The stela includes a large representation of Osiris himself, seated on a throne and holding a long was-sceptre. The principal owner of the stela was shown kneeling before him, no doubt with his hands raised in prayer. Scenes of worship featuring a prominent, seated Osiris became common during the reign of Amenhotep III (c.1390–1352 bc) [10–12].6 It is then that EA 287 was most probably made, at least a century after EA 218 and 299. Another detail often noted from the mid-Eighteenth Dynasty, although only partly preserved on EA 287, is the narrow stand that carries libation paraphernalia: a broad cup and, here no longer figure 5. Stela EA 287 from the late Eighteenth Dynasty, most prob- preserved, a spouted water-jar and lotus flower(s). The ably from the reign of Amenhotep III (c.1390–1352 bc)

25 JEREMY YOUNG, MARCEL MARÉE, CAROLINE CARTWRIGHT AND ANDREW MIDDLETON

SCIENTIFIC EXAMINATION OF THE areas. The limestones from Alexandria are typically porous LIMESTONE SAMPLES calcarenites with ooliths and sand grains that derive from shallow marine environments and date, geologically, to the Geological background Pleistocene age. This is not a facies shown by any of the stelae, making these Pleistocene limestones an improbable source. The Maltese islands are formed of marine Oligocene and The Nile Valley limestones date to the Late Palaeocene and Miocene sediments; see Figure 6 for the geological periods Middle Eocene and are shallow marine shelf limestones. referred to in this section. The main units are the Upper They exhibit diverse facies but typically contain micrites, Coralline Limestone from the Middle to Late Miocene, Blue wackestones and packestones, with common nummu- Clay from the Middle Miocene (clay with abundant plank- litid foraminifera, together with lesser amounts of other tonic microfossils), Globigerina Limestone from the Early invertebrates, especially echinoids, bivalves and alveolinid to Middle Miocene (soft limestone with abundant plank- foraminifera. Calcareous nannofossils are widespread in the tonic microfossils, globigerinid foraminifera and calcareous Egyptian Palaeogene, especially in the marlier facies, and nannofossils) and the Lower Coralline Limestone from the they have been extensively used for biostratigraphy [16]. Oligocene. The coralline limestones are predominantly To summarize, the two alternatives of a Maltese or an hard, shallow marine limestones, composed of coralline Egyptian origin for the stelae lead to distinctly different algae, which is not a facies (rock type) seen in any of the predictions as to the environment of deposition and geolog- four stelae. This leaves the Globigerina Limestone as the only ical age of the rock used. If the stelae are from Egypt, they rock source on Malta that is superficially similar to at least should be either Pleistocene (Alexandria Limestone) or, more some of the stelae and from which they could, theoretically, probably, Palaeocene to Eocene (Nile Valley limestones). In have been made. either case, they would have been deposited under shallow Various igneous, metamorphic and sedimentary rocks marine conditions. In contrast, the only potential rock were used in ancient Egypt to make objects ranging from source in Malta would be the Globigerina Limestone, which small beads to vessels, large sculptural pieces and architec- although superficially similar to the rock of at least some of tural elements [13–15]. Relatively few sedimentary rocks the stelae, is a deep marine limestone of Miocene age. were used, mainly Nubian sandstone from the Cretaceous Fortunately, these hypothetical possibilities could be age and limestones from the Nile Valley and Alexandria tested directly by examining the microfossil content of the rock and by comparing the mineral composition of the stelae with rock samples from quarries in Egypt.

Examination of the microfossils and nannofossils

Initial examination of the stelae and samples of Globigerina Limestone bore out a similarity in general appearance, especially with stelae EA 233 and 218. A more detailed examination was therefore undertaken to identify the nannofossils and microfossils in the stelae. Foraminifera are common in the samples from EA 299 and 287, being clearly visible on the rock surfaces. Extracting these microfossils would have required significant destructive sampling of the specimens, so they were imaged in situ using a binocular microscope. The specimens are clearly shallow benthic rotaliids that, although they cannot be identified to provide useful bios- tratigraphic data, indicate a shallow marine environment. Calcareous nannofossils (size range 2–20 μm) are much smaller than foraminifera and can be adequately sampled from minute scrapings of limestone. To allow their study, a small amount of material was removed with a scalpel from the rear of each stela. Only sparse, poorly preserved assemblages were recovered, but in each case they contained sufficient age-diagnostic taxa to confirm a Palaeogene age; for details see [17, 18]. figure 6. Diagram showing the relationship of the geological • Stela EA 233 (brown weathered, fine creamy lime- periods referred to in the text and the approximate ages of the stones stone) of the stelae deduced from fossil identification and mineralogical : No visible fossils (macrofossils) were seen, but examination the nannofossils included small Reticulofenestra sp.,

26 EGYPTIAN STELAE FROM MALTA

Cribrocentrum reticulatum and Micrantholithus sp. was to try to determine where in Egypt those quarries There are no good marker species in this assemblage, were located. This was achieved by comparing polished but the presence of common Cribrocentrum reticulatum thin sections of samples from the four stelae with refer- is indicative of a Late Eocene to Early Oligocene age. ence samples collected from Egyptian limestone quarries by • Stela EA 218 (chalky limestone): Visible fossils are Dietrich and Rosemarie Klemm that are now held in the present, including some shell fragments, prob- Department of Ancient Egypt and Sudan at the British ably of bivalves, but there is nothing age-diagnostic. Museum. Comparisons were also made with the large Nannofossils are rare; there is an overgrown assemblage corpus of Egyptian limestone stelae [20], which is currently including Prinsius sp., Toweius pertusus, Micrantholithus undergoing scientific analysis at the British Museum [21, sp., Discoaster cf. keupperi and Coccolithus pelagicus. 22]. Small samples were removed from the stelae, made into There are no good marker species in this assemblage, but polished thin sections and examined in the Hitachi S-3700N the presence of common Toweius and Prinsius species is variable pressure scanning electron microscope (VP-SEM) indicative of a Late Palaeocene or Early Eocene age. and Hitachi S-4800 field emission scanning electron micro- • Stela EA 299 (chalky limestone): Visible fossils include scope (FE-SEM). In each case the samples from the stela medium-sized (3–4 mm) rotaliid benthic foraminifera, were compared with Egyptian limestone quarry reference which are best seen on the reverse of the stela. A few specimens from the Klemm Collection that corresponded etched nannofossils are visible, with much recrys- roughly to the date suggested by microfossil and nannofossil tallized calcite. The former included Sphenolithus identification. radians, Coccolithus pelagicus, Zygrhablithus bijugatus and Micrantholithus sp. Although very poorly char- • Stela EA 233: The polished thin section shows a sandy acterized, the general assemblage and presence of limestone with fossil fragments replaced by the recrys- Z. bijugatus suggests an Eocene to Oligocene age. tallization of the limestone, Figure 7a. This matches • Stela EA 287 (pinkish limestone): Visible fossils again mostly closely with reference specimens from the Upper include medium-sized (3–4 mm) rotaliid benthic Eocene Qasr el-Sagha Formation, found in the Fayum foraminifera, which are best seen on the reverse of Oasis area at Qasr el-Sagha on the west bank of the Nile, the stela. Nannofossils, which are very rare, include Figure 8. etched Coccolithus pelagicus, Toweius and small • Stela EA 218: The polished thin section shows a fine- Heliolithus sp. This is a very poor assemblage, but the grained limestone with fossil fragments that have under- presence of Toweius and Heliolithus sp. suggests a late gone partial recrystallization, which severely hinders Palaeocene age. accurate identification, Figure 7b. The sample matches most closely with reference specimens from the lime- None of these limestones contains a diverse or well- stone quarries on the east bank of the Nile south of Asiut preserved nannofossil assemblage, probably due to a at el-Hammamiya (Figure 8), which lie within part of combination of deposition in shallow marine environ- the Drunka Formation of the Thebes Group (Eocene). ments and recrystallization. However, all the assemblages • Stela EA 299: The polished thin section shows a fine- are indicative of Palaeogene age and each sample has a grained limestone containing bioclastic material, somewhat different assemblage, suggesting that they come well-rounded quartz grains and mostly medium-sized from different beds rather than a single source. A Maltese (3–4 mm) foraminifera (nummulites), Figure 7c. In Globigerina Limestone sample was also examined and some of the fossil cavities and in parts of the matrix, contains a poorly preserved but abundant and diverse assem- sparite recrystallization is occasionally present. This blage including Discoaster deflandrei, Helicosphaera perch- sample matches most closely with limestone from nielseniae, H. carteri, H. intermedia, Coccolithus pelagicus, the upper layers at the Mokattam quarry. Within the Clausicoccus fenestratus, Cyclicargolithus floridanus, Mokattam Formation on the east bank of the Nile Pontosphaera sp., Umbilicosphaera jafari, Rhabdosphaera (Figure 8), three very similar limestones can be distin- clavigera and Sphenolithus moriformis. This is an Early guished: Mokattam, Tura and Maasara. Klemm and Miocene assemblage indicative of nannofossil zone NN1–2 Klemm assign the stratigraphic position of the Eocene [19]. Mokattam, Tura and Maasara limestones to the Observ- These observations strongly support a Late Paleocene or atory Formation of the Mokattam Group of the Helwan Eocene shallow marine facies for the rocks of the stelae and facies [13]. indicate, therefore, an Egyptian rather than Maltese origin. • Stela EA 287: The polished thin section shows a fine- grained limestone with a dense micrite matrix, much of which comprises small foraminifera whose cavi- Mineralogical examination of the stelae ties are often filled with fine sparite carbonate, Figure 7d. About 15–20% dolomite is present and this lime- Having established from the nannofossil and microfossil stone matches most closely with the limestones of analysis that the limestones were most likely to have come el-Dababiya and Moalla, Figure 8. According to Klemm from Egyptian limestone quarries, an obvious next step and Klemm these quarries belong to the Esna Forma-

27 JEREMY YOUNG, MARCEL MARÉE, CAROLINE CARTWRIGHT AND ANDREW MIDDLETON

figure 7. Backscattered electron images of polished thin sections of limestone samples from the four British Museum stelae: (a) EA 233; (b) EA 218; (c) EA 299; and (d) EA 287. Images: Hitachi S-3700N VP-SEM (a) and (b); Hitachi S-4800 (c) and (d)

tion in the Upper Palaeocene [13], although Harrell places them in the Tarawan Formation [23].

Discussion

The nannofossil evidence indicates that all the limestone samples date from the Palaeogene, but with each sample exhibiting a somewhat different assemblage, suggesting that they come from different beds rather than a single source. This is substantiated by the VP-SEM examination: EA 233 is of Eocene limestone from the Qasr el-Sagha Formation; EA 218 Eocene limestone from el-Hammamiya; EA 299 Eocene limestone from the upper layers of the Mokattam quarry; and EA 287 Upper Palaeocene limestone from el- Dababiya. It is not surprising that over the course of so many centuries the Abydos workshops acquired limestone supplies from a variety of quarries, but it is more difficult to know why these stones should be from different formations across Egypt. As noted above, the stelae originate from different workshops, and not all of these need necessarily have been located in Abydos itself, as many stelae found figure 8. Map of Egyptian limestone formations (after [23]) in Abydos were brought by their owners from other parts

28 EGYPTIAN STELAE FROM MALTA of Egypt, wherever they lived. It is conceivable, on stylistic ACKNOWLEDGEMENTS grounds, that stela EA 233 in particular has a northern artistic origin. The remaining stelae are, however, most The authors are grateful to Dr Savona-Ventura for prompting this likely to have been produced at Abydos itself, apparently investigation and for supplying the samples of Maltese limestone. At the Natural History Museum, Craig Koch assisted with the nanno- using stone supplies from various parts of Egypt. There fossil analysis and John Whittaker examined the foraminifera. At the could be many mundane, practical reasons for the wide British Museum the authors thank Richard Parkinson, Nicolas Lee range of origins. A major factor, no doubt, was simply and Antony Simpson. which limestone quarries in Egypt were being most actively exploited at a given point in time. As stone was often reused from earlier monuments, the routes from quarry to final stela could be very convoluted indeed. AUTHORS

Jeremy Young ([email protected]) is a researcher in the Palaeontology Department at the Natural History Museum, London. Marcel Marée ([email protected]) is a curator in the Department CONCLUSIONS of Ancient Egypt and Sudan and Caroline Cartwright (ccartwright@ thebritishmuseum.ac.uk) a scientist in the Department of Conservation and Scientific Research, both at the British Museum. Andrew Middleton The observations reported here allow us to conclude with ([email protected]) is an emeritus researcher and a confidence that the four stelae found on Malta in 1829 former member of the scientific staff at the British Museum. were neither produced on the island, nor left there by the Egyptians they commemorate. The styles and content of these pieces point consistently to the necropolis of Abydos in Upper Egypt as their original location. None of the stelae REFERENCES is made of Maltese Globigerina Limestone. Comparison with reference material from Egyptian limestone quarries 1. Murray, M.A., ‘Egyptian objects found in Malta’, Ancient Egypt by VP-SEM and FE-SEM, and with stelae of stones attrib- (1928) 45–51. uted to certain formations, confirms that all four were made 2. Testa, C., ‘Prehistoric antiquities: Egyptian stel[a]e at Bighi’, in Heritage: an encyclopedia of Maltese culture and civilization 74, of Egyptian limestones; this is consistent with the evidence Midsea Books, Valletta (1990) 1473–1477. that the limestones date from the Palaeogene age. The 3. Meza, A.I., ‘Ancient Egypt in Malta: an ancestor bust from the suggestion that the stelae were made on Malta by Egyptian Delta and other objects’, in Egyptology at the dawn of the twenty- colonists is, therefore, unfounded. first century: Proceedings of the Eighth International Congress of Egyptologists Cairo, 2000 Language, conservation, museology It has alternatively been suggested that the stelae came to , 3: , ed. Z. Hawass and L.P. Brock, American University in Cairo Press, Malta in Roman times [3; p. 313], having been taken there Cairo and New York (2003) 307–314. as ship’s ballast. However, no other Egyptian monuments 4. Savona-Ventura, C., Gharghur, Malta, personal communications are known to have been taken abroad as ‘ballast’. More to R. Parkinson, 20 and 24 August 2003. importantly, it is hard to see why ballast would have been 5. Pierret, P., Recueil d’inscriptions inédites du musée égyptien du Louvre obtained, not from a Nile Delta site on the Mediterranean , II, Vieweg, Paris (1878) 50. 6. Gayet, A.-J., Musée du Louvre: stèles de la XIIe dynastie, Vieweg, coast, but all the way from Abydos in Upper Egypt, having Paris (1886). first been carried from the cemeteries to a river vessel and 7. Hölzl, R., ‘Die Giebelfelddekoration von Stelen des Mittleren later re-employed on a seafaring ship that docked in Malta. Reichs’, Beiträge zur Ägyptologie 10, Afro-Pub, Vienna (1990). As this reconstruction is implausible, it is difficult to avoid 8. Fischer, H.G., Varia Nova, Egyptian Studies 3, Metropolitan the conclusion that the stelae left Egypt at a much more Museum of Art, New York (1996) 141–176. Stèles du nouvel empire recent date than has been considered heretofore. It must be 9. Lacau, P., , Institut français d’archéologie orientale, Cairo (1957). recalled that there is no documentation on the context from 10. Hieroglyphic texts from Egyptian stelae, &c., in the British Museum which the stelae were lifted in 1829, and there is no compel- V, British Museum, London (1914). ling reason to think that they had lain there since antiquity. 11. Hieroglyphic texts from Egyptian stelae, etc., VIII, ed. I.E.S. A possibility not previously suggested is that they reached Edwards, British Museum, London (1939). Hieroglyphic texts from Egyptian stelae etc. IX Malta at the time of Napoleon I, shortly after he conquered 12. , ed. T.G.H. James, British Museum, London (1970). the islands in 1798 en route to Egypt. Perhaps the stelae 13. Klemm, R. and Klemm, D.D., Steine und Steinbrüche im Alten- had been collected by his savants when they rediscovered Ägypten, Springer-Verlag, Berlin (1993). Abydos at the very end of the eighteenth century. The stelae 14. Aston, B.G., Ancient Egyptian stone vessels: materials and forms, may have been on their way to France when they were aban- Studien zur Archäologie und Geschichte Altägyptens 5, Heidel- doned in Valletta’s harbour, perhaps amid the chaos of the berger Orientverlag, Heidelberg (1994). 15. Aston, B., Harrell, J. and Shaw, I., ‘Stone’, in Ancient Egyptian mate- Maltese insurrection that ended in September 1800, when rials and technology, ed. P.T. Nicholson and I. Shaw, Cambridge Malta came under British control. University Press, Cambridge (2000) 5–77. 16. Tantawy, A., ‘Calcareous nannofossils of the Paleocene-Eocene transition at Qena region, Central Nile Valley, Egypt’, Micro- paleontology 52 (2006) 193–222.

29 JEREMY YOUNG, MARCEL MARÉE, CAROLINE CARTWRIGHT AND ANDREW MIDDLETON

17. Perch-Nielsen, K., ‘Cenozoic calcareous nannofossils’, in Plankton NOTES stratigraphy 1: planktonic foraminifera, calcareous nannofossils, and calpionellids , ed. H.M. Bolli, J.B. Saunders and K. Perch-Nielsen, 1. This stela is yet to be published. A brief mention appears in Pierret Cambridge University Press, Cambridge (1985) 427–555. [5], and concise notes and an unreliable drawing are given in 18. Romein, A.J.T., ‘Lineages in Early Paleogene calcareous nanno- Gayet [6; p. 3; Plate 10 and corrigenda]. plankton’, Utrecht Micropaleontological Bulletin 22 (1979) 231. 2. A systematic study of lunette decoration on Middle Kingdom 19. Young, J.R., ‘Neogene’, in Calcareous nannofossil biostratigraphy, stelae has been made by Hölzl [7]. However, her drawings omit ed. P.R. Bown, British Micropalaeontological Society Publications the ankh-signs with Wepwawet on EA 233 [7; p. 140], and with Series, Chapman and Hall, London (1998) 225–265. Osiris on Louvre C 6 [7; Plate 17:2], the latter clearly based on a 20. Franke, D. and Marée, M. (eds), Egyptian stelae in the British mistake made by Gayet [6; Plate 10]. Museum from the Thirteenth to Seventeenth Dynasties, British 3. On the British Museum stela, Wepwawet’s epithet ‘lord of the Museum Press, London (forthcoming). sacred land (i.e. the necropolis)’ is written defectively as nb 21. Cartwright, C.R. and Marée, M., ‘Petrographic examination Dsr. The different reading offered by Meza [3; p. 310]( *nb xrp R- of Egyptian limestone stelae of the Middle Kingdom in the sTAw) is impossible. British Museum: some questions and answers’, in Petrography of 4. For surviving examples of such chairs see, notably, a study by H.G. archaeological materials, ed. P.S. Quinn, Archaeopress, Oxford Fischer [8]. (forthcoming). 5. See, for instance, two stelae from the Cairo Museum (CG 34109 22. Cartwright, C.R., Hook, D. and Fletcher, P., ‘Recent petrographic and 34110). A similarly small table, but with the loaves shown and chemical analyses of Thirteenth to Seventeenth Dynasty larger and distinguished from each other, appears in the liba- Egyptian stelae in the British Museum’, in Egyptian stelae in the tion scene on CG 34105, which was also found in Abydos. All British Museum from the Thirteenth to Seventeenth Dynasties, three stelae are illustrated in their principal publication [9; Plates ed. D. Franke and M. Marée, British Museum Press, London 51–52]. (forthcoming). 6. It may also be noted that praying individuals shown kneeling, 23. Harrell, J.A., ‘Ancient Egyptian limestone quarries: a petrological rather than standing, seldom appear on stelae before Thutmose survey’, Archaeometry 34 (1992) 195–211. IV–Amenhotep III (c.1400–1352 bc), one example being BM EA 932 [10; Plate 22]. Examples from the reign of Thutmose IV include BM EA 1515 [11; Plate 45] and probably BM EA 345 [12; Plate 46 (2)], although the latter has been misdated to the Nineteenth Dynasty [12; p. 345]. Examples from the time of Amenhotep III include BM EA 358 [10; p. 962 and Plate 43] and BM EA 1743 [11; Plate 42].

30 Analysis of a gold mancus of Coenwulf of Mercia and other comparable coins Gareth Williams and Michael Cowell

Summary A gold mancus of Coenwulf, king of Mercia (ad 796–821), found in 2001, was subjected to material and stylistic analysis and compared to other Anglo-Saxon gold coins before its acquisition by the British Museum in 2006. Examination by scanning electron microscopy revealed that in common with the comparative coins, the Coenwulf mancus was die-struck, although its unusually well-preserved state revealed die preparation features not visible to the naked eye on the other coins. Analysis by X-ray fluorescence spectrometry showed that the coin was made from an alloy of gold, silver and copper with a high, but not exceptional, gold content. The high gold content may lie behind the lack of stress-corrosion cracking on the newly found coin. Stylistic analysis is consistent with coins struck from dies made by a die cutter who normally produced dies for Canterbury moneyers, although the coin was probably minted in London. Both the material and stylistic evidence suggest the coin is a genuine gold mancus of Coenwulf.

INTRODUCTION (apparently recent) scratch immediately visible in front of the bust on the obverse. A unique gold coin in the name of Coenwulf, king of Mercia Both the lack of a direct parallel for the coin and its (ad 796–821), was discovered in 2001 by a metal detec- recently struck appearance made it essential to establish, torist, close to the bank of the River Ivel near Biggleswade in so far as this is possible, that the coin was genuine, in Bedfordshire, UK, Figure 1. The coin weighs 4.33 g, has before its acquisition could proceed. This was done partly a diameter of 21 mm, and has been identified as a ‘mancus’, by comparing the style of the die cutting with Coenwulf’s a term used of Anglo-Saxon gold coins in documentary extensive silver coinage, and partly by scientific analysis sources of the period [1–3]. The coin was initially offered of the new coin, comparing it with other available Anglo- to the British Museum by the finder, but a lengthy investi- Saxon gold coins. Six of the seven other examples are in the gation established that title to the coin was shared between British Museum collection and were thus available for study. the finder and landowners, who eventually decided to put Most of these had previously been measured for fineness the coin up for auction in October 2004. Having failed to by specific gravity, but none had been examined by more secure the coin at auction, the British Museum subsequently modern analytical techniques, so this comparative study succeeded in acquiring the coin (British Museum registra- provided an opportunity to look at these coins in more tion number CM 2006,0204.1) in February 2006, following a ban on its export.1 After an early phase of gold coinage in the seventh century, Anglo-Saxon gold coins are extremely rare. Between the mid-eighth century and the Norman conquest in 1066, only eight gold Anglo-Saxon coins are recorded, with no further English gold coins recorded before the reintro- duction of gold coinage under Henry III in the 1250s. The Coenwulf coin itself is unique and is also in exceptional condition. The stability of gold means that gold coins tend to be better preserved than those made of silver or copper alloys, but the newly acquired coin appeared to show almost no sign of wear before its deposition, with only a single large figure 1. Gold mancus of Coenwulf of Mercia (2006,0204.1)

31 GARETH WILLIAMS AND MICHAEL COWELL detail than had previously been possible. All seven coins, XRF ANALYSIS seen in Figures 1 and 2, and listed in Table 1 in chronological order, were therefore examined by optical and scanning The coins were analysed non-destructively by XRF to give electron microscopy (SEM) and analysed by X-ray fluores- semi-quantitative elemental analyses, see Table 1. The preci- cence (XRF) spectrometry [3, 4].2 sion (reproducibility) of these XRF results is about (1–2%

(a) (b)

(e) (f)

figure 2. The six comparative mid- to late-Anglo-Saxon gold coins in the British Museum collection, in chronological order: (a) oldg dinar of Offa of Mercia; (b) gold mancus of the moneyer Pændræd; (c) gold mancus of the moneyer Ciolheard; (d) gold solidus of Archbishop Wigmund of York; (e) gold mancus of Æthelræd II; and (f) gold mancus of Edward the Confessor (see Table 1)

table 1. The seven gold Anglo-Saxon coins examined in this study and their elemental compositions determined by XRF British Museum Description Figure XRF analysis results No. Gold (%) Silver (%) Copper (%) 1913,1213.1 Gold dinar of Offa of Mercia (757–796) 2a 94 5.5 0.4 1962,0313.1 Gold mancus of the moneyer Pændræd, temp Offa 2b 95 2.3 2.8 1984,1221.1 Gold mancus of the moneyer Ciolheard, temp Offa or 2c 83 14.5 2.6 Coenwulf 2006,0204.1 Gold mancus of Coenwulf (796–821) 1 99 1.0 0.1 1848,0819.171 Gold solidus of Archbishop Wigmund of York (c.837–854?) 2d 92 6.0 1.7 1883,0516.1 Gold mancus of Æthelræd II (978–1016), Helmet type, 2e 93 7.0 0.3 moneyer Leofwine of Lewes 1951,0601.1 Gold mancus of Edward the Confessor (1042–1066), 2f 99 1.5 nd Expanding Cross type, moneyer Lyfinc of Warwick

Note: ‘nd’ denotes that copper was not found above the detection limit of 0.05%

32 ANALYSIS OF A GOLD MANCUS OF COENWULF OF MERCIA AND OTHER COMPARABLE COINS relative for gold, (5–10% for silver and (10–20% for copper. The accuracy cannot be defined as the analysis is predominantly of the surface and this may not be fully representative of the bulk composition. The gold content in each case is likely to be overestimated due to surface depletion of the silver and particularly the copper. This is caused by slight dissolution of these more reactive metals in the burial environment; since the compositions must be normalized to 100%, the result is a corresponding increase in the reported gold content. The effect is usually small, unless the burial environment is very acidic, and would result in differences smaller than those between the analyses given in Table 1, which indicate a real range in composition. The Coenwulf coin, in common with the comparative examples, is thus a gold alloy containing silver and copper. figure 3. Secondary electron image in the SEM of the gold mancus of Coenwulf, showing striations on the edge beading due to die striking. Although it has a comparatively high gold content, the coin Scale bar length 500 μm of Edward is of very similar composition.

OPTICAL AND SCANNING ELECTRON MICROSCOPY (SEM)

The expected method of manufacture of the Coenwulf coin, and the others being examined, would be by striking between a pair of dies. The clearest evidence of this, surface flow lines indicating metal movement under the dies, is visible on the Coenwulf coin at the beaded edge (Figure 3), indicating that the coin is probably die-struck. Similar features were observed on most of the other coins, where these have not been obliterated by wear. Wear traces on the Coenwulf coin are slight and confined to the highest points of the design, with some minor scratches and damage to the surface, Figure 4. The coin has clearly not experienced much handling. The compara- figure 4. Secondary electron image in the SEM of the gold mancus tive coins show different degrees of wear ranging from the of Coenwulf, showing traces of wear, including slight scratches on the face. Scale bar length 200 μm major wear on, for example, the Pændræd mancus to slight wear on the Edward the Confessor mancus, although even the wear on the latter is greater than that of the Coenwulf coin. A distinctive feature on the Coenwulf coin is a cross- hatched pattern of fine raised lines on the flat field of the coin; these are visible on both faces but not present on any of the raised parts of the design or lettering, Figure 5. This feature is reminiscent of the effects of cleaning up a die face using a file or similar tool prior to, or after, punching in the lettering or design. A file could produce a series of parallel scratches, which would be cross-hatched if applied in two directions. This would not be present on the incuse design areas on the die, as these areas would be protected from the filing or added after the filing had been carried out. If not removed by subsequent polishing, the file marks would be transferred to any coin struck by the dies and show as raised lines. Similar marks were observed on all but one of the comparative coins; the exception was the mancus figure 5. Secondary electron image in the SEM of the gold mancus of of Pændræd, but this coin is heavily worn. None of the Coenwulf, showing impressions of the filing marks from die prepara- comparative coins show these marks as extensively as the tion. Scale bar length 1 mm

33 GARETH WILLIAMS AND MICHAEL COWELL

Coenwulf coin and in some cases they are only visible on one face. The extent of the survival of these marks on the Coenwulf coin is an indication of the limited amount of wear this coin has received. The Coenwulf mancus was examined for signs of stress- corrosion cracking but no clear indications of this were observed. Such cracking follows the equiaxed (annealed) grain boundaries. In alloys with a high gold content, such as that used for the Coenwulf coin, this cracking, if it occurs at all, is generally considered to develop only over long periods of time. However, for base alloys (generally those with high copper contents) it can develop over a much shorter time. Some cracks were observed on the head area of the obverse (Figure 6), and also near the beaded edge, but these do not seem to follow grain boundaries as would be expected figure 6. Secondary electron image in the SEM of the gold mancus of Coenwulf, showing surface cracks in the head area on the obverse. for stress cracking; they may instead be residual flaws in Scale bar length 500 μm the coin blank. Some cracks on the other coins examined could be attributed to stress cracking, for example on the Æthelræd coin, Figure 7. This coin has a slightly baser composition than the Coenwulf mancus (Table 1) and is therefore more likely to have developed stress cracking. It is notable that the coin of Edward, of similar composition to the Coenwulf coin, did not show any clear signs of stress- corrosion cracking. Comparison of the grain structures and grain porosities of these two coins also shows strong similarities. The Coenwulf coin has traces of what appear to be grey or reddish soil residues between some of the edge beading; small quantities of these residues can also be seen in porosities in the coin face, Figure 8. Analyses of the deposits at the edge by energy dispersive X-ray analysis in the SEM showed these to be siliceous with moderate amounts of calcium and iron, along with other elements, such as aluminium, all of which are consistent with a soil origin. The coin was report- edly found on Biggleswade Common in Bedfordshire and figure 7. Secondary electron image in the SEM of the gold mancus of although an XRF analysis of soil collected from this area Æthelræd, showing cracking that is possibly indicative of stress corrosion. Scale bar length 200 μm showed a similar elemental composition to the residues on the coin, it should be noted that such soils are very common throughout lowland Britain. Finally, the Coenwulf and comparative coins were also examined by optical microscopy and XRF spectrometry for the presence of platinum group element (PGE) inclusions, material which may be characteristic of alluvial gold, but none was found on any of the coins.

STYLISTIC ANALYSIS

Stylistic analysis of the Coenwulf mancus is based on comparison, not with the other gold coins, but with the extensive silver penny coinage in the name of Coenwulf. Like his better-known predecessor Offa, Coenwulf was a Mercian king who also succeeded in establishing himself as ruler over Kent and East Anglia. Coins were issued in his figure 8. Secondary electron image in the SEM of the gold mancus name in all three kingdoms and most coins can be attrib- of Coenwulf, showing siliceous material in some of the cavities. Scale uted with reasonable certainty to one of the three kingdoms, bar length 200 μm

34 ANALYSIS OF A GOLD MANCUS OF COENWULF OF MERCIA AND OTHER COMPARABLE COINS

(a)

(b)

figure 9. Comparative coins: (a) silver penny of Coenwulf, moneyer Oba of Canterbury; and (b) gold solidus of Charlemagne

although the coins do not carry mint signatures. In some Cuthred, sub-king of Kent under Coenwulf (798–807) [5].3 cases the identification of the mint comes from the fact that The lettering on the reverse inscription is in the same style the moneyers concerned also struck coins for other known and, typically for this period, the reverse design is based individuals specific to one kingdom, namely East Anglian around an ornate cross. In this variety, the terminals of the or Kentish kings, or the archbishops of Canterbury. In other limbs of the cross meet and curve back to the centre, creating cases, the moneyers who are otherwise unidentified can be the effect of a flower with eight petals. Again, a direct parallel attributed to a particular kingdom because of stylistic simi- can be found on a Coenwulf penny of the Canterbury larities with other moneyers who can be identified securely. moneyer Oba (CM 1854,0621.18: Figure 9a). However, the Minting in Kent was centred on Canterbury, while minting reverse inscription reads DE VICO LVNDONIAE (‘From in Mercia appears to have been centred on London [5, 6]. the vicus of London’). The choice to describe London as a However, the stylistic similarities that have led to identifi- vicus (from the Old English wic, meaning a trading centre) cation with particular mints indicate that specific groups rather than a civitas (city), or simply to give the name of of dies came from a common source, rather than that they London without further qualification, has direct paral- were all necessarily used for minting in the same place. This lels with a gold solidus of the Frankish ruler Charlemagne distinction is important, because of a peculiarity of the new (768–814), which bears the inscription VICO DORESTAT Coenwulf coin. (CM G3, FrGC10: Figure 9b). It seems likely that The obverse of the coin shows a right-facing Coenwulf’s gold coinage should be interpreted at least in stylized Roman imperial diademed bust, with the inscription part as a response to the introduction by Charlemagne of a COENWULF REX M, with a contraction mark over the regal coinage in gold, in the wider context of international M, the standard contraction for Merciorum, giving a full one-upmanship between rulers [7, 8]. inscription ‘Coenwulf, king of the Mercians’. The style of The London mint signature combined with a Canter- both the bust and the inscription places this coin firmly in the bury style could be seen as problematic if the stylistic Canterbury issues of both Coenwulf and his brother associations are directly associated with minting. A forger

35 GARETH WILLIAMS AND MICHAEL COWELL might, for example, have been inspired by the idea of the ACKNOWLEDGEMENTS Charlemagne solidus, but have copied designs from a Canterbury coin. However, if the styles are seen as linked The authors are grateful to Stewart Lyon for useful discussion of as much with die cutting (which could just as easily have numismatic style, to Rory Naismith for comments on the paper in draft and to Duncan Hook both for his comments and his assistance taken place in London as Canterbury) as with actual with the images. minting, this ceases to be a problem. The selection of this particular die-cutter to produce dies for the gold coinage may have been entirely random, or may reflect recognition of his skill. The coins with which the mancus can AUTHORS be most closely linked are amongst the most attractive of Coenwulf’s silver pennies, and it is likely that it was deliber- Gareth Williams ([email protected]) is a curator in ately planned that the mancus, as a high-status coin, should the Department of Coins and Medals at the British Museum. Michael look as impressive as possible. Cowell was, prior to retirement, a scientist in the Department of Conservation and Scientific Research.

CONCLUSIONS REFERENCES

The microscopic examination of the Coenwulf mancus 1. Lyon, C.S.S., ‘Historical problems of Anglo-Saxon coinage (3), shows features that are consistent with manufacture by die denominations and weights’, British Numismatic Journal 38 (1969) striking, the expected method of production, in common 204–222. 2. Naismith, R., ‘Islamic coins from Early Medieval England’, with all the other Anglo-Saxon gold coins studied. The Numismatic Chronicle 165 (2005) 193–222 excellent state of preservation for the coin is unusual as it 3. Blackburn, M.A.S., ‘Gold in England during the ‘Age of Silver’’, shows only slight evidence of wear and would have to have in Silver economy in the Viking Age, ed. J. Graham-Campbell and been almost as struck when deposited. There is little sign G. Williams, Left Coast Press, Walnut Creek (2007) 55–98. 4. Williams, G., ‘Anglo-Saxon gold coins’, British Numismatic Journal of any recent damage other than a few minor scratches and 80 (2010) forthcoming. although this might be explained by the coin having been 5. Blunt, C.E., Lyon, C.S.S. and Stewart, B.H.I.H., ‘The coinage of in a protected environment, such as a container, there is southern England, 796–840’, British Numismatic Journal 32 (1963) 1–74. no information on this aspect of the find. In contrast, the 6. Stewart, B.H.I.H., ‘The London Mint and the coinage of Offa’, in comparative examples show more wear, which in at least Anglo-Saxon monetary history, ed. M.A.S. Blackburn, Leicester one case is extensive. The lack of wear on the Coenwulf University Press, Leicester (1986) 27–43. British Museum Magazine coin has contributed to the survival of some die prepara- 7. Williams, G., ‘Striking gold’, 55 (Summer 2006) 36–38. tion features in the form of file marks. These were observed 8. Williams, G., Early Anglo-Saxon coins, Shire Publications Ltd, on almost all the comparative coins, albeit less extensively, Oxford (2008) 43–45. and generally with similar patterning and dimensions. The composition of the coin is consistent with other Anglo-Saxon coins of similar date and although of higher gold content than most it is very similar to one of the NOTES comparative coins. No definite stress-corrosion cracks were observed, but neither were these evident on the coin 1. The coin was acquired with the generous assistance of the National Heritage Memorial Fund, the Art Fund, the Goldsmiths’ of Edward that is closest in composition to the Coenwulf Company Charity, the British Museum Friends and a number of mancus. private donations. The stylistic analysis is also entirely consistent with this 2. Further details of these coins, together with an eighth (a gold being a genuine coin of Coenwulf, struck from dies produced mancus of Edward the Elder in the Musée Cantonal, Lausanne), and a more general discussion of the use of gold in England in the by a die-cutter who normally produced dies for Canterbury period, can be found in [3]. The eight coins will also be discussed moneyers (although not necessarily exclusively). further, together with coins of the earlier phase of Anglo-Saxon Furthermore, as a result of this investigation, we are also gold coinage, in [4]. 3. For example, there are clear similarities to the dies of Coenwulf now better informed about the composition and aspects 29 and 31 and Cuthred 18 and 22 (between them representing a of the manufacture of the other comparable coins in the variety of moneyers) in [5]. The authors are grateful to Stewart British Museum collection. Lyon for useful discussion of this point.

36 Early porcelain in seventeenth-century England: non-destructive examination of two jars from Burghley House Michela Spataro, Nigel Meeks, Mavis Bimson, Aileen Dawson and Janet Ambers

Summary This contribution focuses on the investigation of seventeenth-century porcelain from the collection at Burghley House, Stamford, Lincolnshire, using non-destructive scanning electron microscopy (SEM) with energy dispersive X-ray spectrometry (EDX) and Raman spectroscopy. The glaze and body of three seventeenth-century objects, a small jar, its lid and a larger jar, were analysed by SEM-EDX using the variable pressure (VP) mode to allow the surface of the jars to be examined directly and without damaging these objects by the need to take samples. Both this new application of direct VP observation and analysis of ceramic vessels and the limits of the method are discussed, as well as the possibilities for obtaining results that are directly comparable to those acquired by standard methods that require intrusive sampling. The EDX analyses of the bodies of the two jars suggest that they were produced using a similar paste, high in clay content, while analysis of the lid suggests that it was made using a different paste, perhaps at a different time or by a different artisan; this mismatch is supported by differences in decoration and the poor fit between lid and jar. The glaze analyses indicate variable concentrations of lead, which may partly derive from the pigments and variations in the thickness of the glaze. The pigments used to decorate the small and large jars were also studied by Raman spectroscopy, indicating the use of haematite. The results from the two jars show that the porcelain is different to that produced at Fulham by John Dwight and in Dehua as ‘blanc de Chine’.

INTRODUCTION questions concerning the jars from Burghley House that are the subject of this study was of what type of porcelain Porcelain was first made in China in the sixth century ad they are made; that is, whether they are ‘soft paste’ or ‘hard [1]. Since its arrival in Europe in the fourteenth century, this paste’ (although the use of these terms can be problematic). beautiful, translucent, glassy and expensive product became True hard-paste porcelain was made from a mixture of feld- a prestigious and luxurious item for European collectors spar (china stone) and a clay derived from the decomposi- [2]. From the sixteenth century onward in many European tion of feldspar (china clay). This porcelain was imported countries, such as Italy, France, Germany and England, into Europe from the Jingdezhen region in Jiangxi Province, much energy and capital were invested in trying to pursue China and from the Dehua region in southern China. Hard the secret of the ‘Arcanum’ [3]. paste was eventually manufactured in Europe, initially at As Freestone has noted [3; p. 19], imperial Chinese Meissen in c.1720 [8]. porcelain was made from a mixture of kaolin and the porce- This contribution compares the composition and manu- lain stone petuntse, containing mica, feldspar and quartz, facture of some porcelain vessels from the Burghley House which was then fired at high temperature. Dehua porcelain collection with known (published) porcelains from China was made of porcelain stone “without kaolin addition” and and Britain to determine their most probable place and in which “the iron oxides levels … could be as low as 0.2%” date of manufacture. The paper also examines the appli- [4; p. 69]. cation of variable pressure (VP) scanning electron micro- The composition of early English porcelains has been scopy (SEM) for the direct microscopic examination of studied in recent decades [3, 5–7], and one of the main large non-conducting vessels. The associated in situ energy

37 MICHELA SPATARO, NIGEL MEEKS, MAVIS BIMSON, AILEEN DAWSON AND JANET AMBERS

figure 1. The two Burghley House porcelain jars and lid, the larger being the ‘Virtues jar’. The elegant decoration is from a palette of red, green, black and gold

dispersive X-ray spectrometric (EDX) analysis of existing Lincolnshire, where the vases have been kept since at least fractured surfaces on the porcelain and glazed surfaces is around 1690, prior to which they were at Chatsworth fundamental to their characterization, but in VP mode House, Derbyshire. In later documents the vases have been (compared to conventional high vacuum SEM analysis described as ‘the Duke of Buckingham’s china’. Although of carbon-coated materials) there are certain analytical it is not currently possible to attribute them firmly to any characteristics that require critical evaluation to ensure English factory, their English origin is thought likely. The that the analyses are accurate, consistent and comparable decoration is dissimilar to that found on any other known to conventional EDX analysis. In particular, the effects of porcelains apart from a related vase in a private collection. electron beam ‘skirting’ (scatter), due to the presence of the Both the three allegorical scenes on the ‘Virtues jar’ and the controlled trace of air in the SEM needed to be studied to heads on the smaller jar are consistent with a date in the ensure the correct working parameters for this analytical second half of the seventeenth century. approach are fully understood for future routine applica- The main research objectives were to identify the chem- tion of direct analysis in the VP-SEM-EDX. ical composition of the three objects, to see whether there are similarities or differences between them, as well as clar- ifying whether the lid originally belonged to the small jar.1 In particular, the analyses aimed to determine the type of THE BURGHLEY HOUSE JARS porcelain body and the nature of the glaze and colorants. For curatorial reasons at Burghley House, the time The Burghley House porcelain vessels chosen for this study available to study the jars was restricted, and it was there- are the so-called ‘Virtues jar’ (height c.75 mm), named for fore necessary to employ techniques that could be imple- the allegorical scenes painted in three medallions, and a mented rapidly. The objects were first studied by reflected small jar and cover decorated with putti and scrolls (height light microscopy, to locate suitable areas of white paste, c.44 mm), which is one of a pair, Figure 1. coloured decorated areas and existing fractured surfaces, Both pieces are important because of their early date. before studying their chemical composition by SEM-EDX. They can be traced in the Devonshire Schedule of Deed, The Virtues jar paste could be analysed at an existing crack drafted in 1683 and proved in 1690 after the death of Lady on the side of the vessel, and at a chip on the rim (Figures Elizabeth Cavendish, the mother-in-law of the fifth Earl of 2 and 3), while chips on the small jar and lid offered sites Exeter [9; p. 20, 10]. This document is at Burghley House, for analysis.

38 EARLY PORCELAIN IN SEVENTEENTH-CENTURY ENGLAND

METHODS

Only non-destructive analytical techniques could be considered. The natural choice to conduct qualitative and quantitative analyses and microstructural observation and photomicrography was the Museum’s new VP-SEM, a Hitachi S-3700N. This instrument allows high- magnification images to be produced (from 7= to several thousand times), using a focused scanned electron beam. It is used in combination with the Oxford Instruments INCA energy dispersive X-ray spectrometer for quantitative elemental compositional analysis. The Hitachi S-3700N has two main advantages over previous SEMs for the study of porcelain. First, it has a large specimen chamber, allowing objects up to 200 mm in diameter and 65 mm high to be examined; these can be stood on the specimen stage, or figure 2. The large Burghley Virtues jar resting safely on a graphite laid on their sides if they are too high. Secondly, the VP plate on the large x-y stage of the VP-SEM. The existing crack on the mode enables a wide range of non-conducting samples (for side of the vessel where a fragment is missing (detail in Figure 3) and a chip on the rim are where the analyses were made example, pottery, ceramics, wood, glass, bone and other organic materials) that cannot be examined in a conventional high vacuum SEM to be studied at a range of volt- ages without being coated with a thin layer of carbon or gold [12]. A controlled amount of air is introduced into the vacuum chamber at low pressure (in the range 6–40 Pa) to counteract charge build-up on the sample surface, which would otherwise prevent observation and analysis. The paste and glaze of the two jars and the lid were analysed to identify compositional similarities and differences. The 17 or 18 elements representing the range of characteristic ceramic constituents, opacifiers and colorants (Na, Mg, Al, Si, P, K, Ca, Ti, Mn, Fe, Pb, Ba, Sb, Sn, Cu, and S, with Au and Hg in cases where gilding is present) were quantified. The results were converted into oxide percentages (oxygen by stoichiometry) and normalized to account for not measuring oxygen and carbon. Glass standards were used for the analytical calibration and standardization of figure 3. Reflected light microscope montage-image (40=) featuring the system. To ensure that the bulk analyses were represent- the fractured hole in the side of the large Virtues jar. This has clearly exposed a cross-section of the white porcelain and the transparent ative of the material, replicate analyses were generally made surface glaze, which allows direct VP-SEM study and analysis on three to eight areas (depending on the size of the object or fractured surface) and the mean values determined. The analyses were typically made at an SEM image magnification of 50–90=, selecting areas of c.1 = 1.5 mm (c.0.2 = 0.4 mm for associated homogeneous glazed layers) for bulk analysis within these images. Spot analyses (with a diameter of c.5 μm) were only made to identify particular small constituents or thin layers. To minimize any scattered signals, the objects were mounted on a graphite plate that was attached to the large SEM stage and placed in the specimen chamber, Figures 2 and 4. Particular attention was paid to the orientation of the object or fracture section in order to position the areas to be analysed as close as possible to the ideal geometry for analysis, i.e. normal to the electron beam to give the figure 4. The Hitachi S-3700N Variable Pressure SEM used for the appropriate take-off angle for the X-ray detector (30°), and porcelain examination. The large jar is on the sample stage ready to be inserted into the very large sample chamber. The analytical X-ray with any potential regions of scatter on the object, such as detector is the blue device on the left side of the chamber. There are the curved sides of the jar, pointing away from the X-ray two large high-resolution imaging screens, one displaying the visible detector. image of the pot

39 MICHELA SPATARO, NIGEL MEEKS, MAVIS BIMSON, AILEEN DAWSON AND JANET AMBERS

Instrumentation parameters from 6 to 100 Pa was tested. At lower pressures skirting is reduced but charging may occur, while at higher pres- Prior to analysis of the Burghley jars, various experi- sures skirting will increase, reducing the image resolution. ments were undertaken to assess the accuracy of quanti- Extensive use of the system at 20–30 Pa proved most satis- tative analysis by VP-SEM-EDX on fractured, unpolished factory and this is now established as the normal working or uncoated samples and objects that could potentially range for most ceramic examinations. give unexpected or inaccurate results when compared to polished and coated thin sections – the ‘ideal samples’ for a conventional SEM. An example of such a difference Tests on polished ceramic thin sections framed with is the so-called ‘skirting effect’, created by the interac- copper strips tion of the electron beam with the low air pressure in the chamber, which can cause a small proportion of the elec- At the normal analytical working distance of 10 mm, it trons to scatter outside the area of analysis. was possible to analyse the ceramic thin section as close as These empirical measurements were intended to estab- 1 mm from the copper test strip with no observable copper lish the practical working conditions and potential for peaks in the spectrum. While analysing the same area with a direct, non-invasive VP-SEM examination and analysis, 20 mm working distance, only a small peak for copper methods that have previously been impossible on large due to skirting was observed. When fractured sherds of ceramic objects. porcelain or pottery are analysed, the sherd wall stands vertically with the fractured edges, which are typically up to several millimetres thick, horizontal. In this orienta- Raman spectrometry tion the effects of skirting, and consequently the contribution of extraneous analytical information, are at best Attempts were made to analyse the pigments in a number not seen and at worst are minimal and can be further of the coloured areas under the glaze of the large and small reduced by adjusting the orientation of the object or even jars using Raman spectrometry. The size and shape of the by masking an area with removable thin carbon tape. pieces meant that it was only possible to carry out this For the surface examination of decorated porcelain pots, investigation non-invasively by using the horizontal side consideration is given to potential skirting effects when arm of the spectrometer, which can be difficult to focus. analysing different coloured glazes or pigmented areas to ensure that extraneous signals from adjacent colours do not affect the results.

ASSESSMENT OF ACCURACY OF VP-SEM-EDX Comparison of analyses on uncoated fractured and The analyses were made with the SEM at 20 kV, which uncoated polished samples: Dehua (blanc de Chine) is the usual voltage for ceramic analysis. Measurements porcelain samples were made at various working distances to cover the range of possibilities that might be used in future examinations To identify any differences that might occur between of fractured objects. the results obtained from analysis of an uncoated fractured sample in the VP-SEM and analysis of an uncoated polished section of the same material, the fractured edge The skirting effect of a fragment of a small bowl from the Jaibei old kiln site in Dehua and a polished thick section from the same bowl Examination of non-conducting materials and samples were analysed in the Hitachi S-3700N in VP mode at a such as porcelain by VP-SEM simply requires a very pressure of 30 Pa, Figure 5. Three bulk analyses of the paste low pressure of air to be admitted and maintained in the and the glaze were carried out on the unpolished fracture vacuum chamber to neutralize the electron charge at the sample and the results averaged. Given the homogeneity surface of the material, and consequently allow micro- of the polished sample, and proven reproducibility of the scopic observation, microphotography and analysis to be analyser, only one bulk analysis was carried out on both carried out. paste and glaze. Encouragingly, the results from the paste In VP-SEM, most of the electron beam remains of the fractured, unpolished sample are virtually the same coherent and fully focused, allowing high-resolution as those from the polished section, Table 1. The glaze in imaging and analysis. A small proportion of the primary the unpolished sample shows higher silicon content (SiO2: electron beam is, however, scattered in a conical fashion 68.6 versus 66.0%) and lower calcium content (CaO: 7.2 as the beam passes through the air before reaching the versus 9.4%) than the glaze in the polished section; as the object surface – this is the skirting effect [12]. glaze is a very thin layer, this is perhaps due to the orien- Ideally, the minimum pressure that neutralizes the tation of the sample. electron charge should be used, so a range of pressures

40 EARLY PORCELAIN IN SEVENTEENTH-CENTURY ENGLAND

Comparison of analyses on polished coated and uncoated Analytical accuracy of fractured ceramics versus polished samples samples: the Eccles porcelain samples

Comparing the composition of the polished Dehua porce- Some English porcelain objects from the Eccles collection, lain sample analysed uncoated in the VP-SEM with the same which had already been extensively studied [13], were lent sample carbon-coated and analysed in the high vacuum to the authors by the Victoria and Albert Museum. The anal- Hitachi S-4800 field emission scanning electron micro- ysis of five of these objects is considered in [7; appendix]: scope (FE-SEM) gave the same results within statistical analytical errors. This is to be expected, as the absorption • A saucer, decorated in polychrome enamels, made in of the emitted X-rays by the residual air in the VP chamber Bristol; c.1775; catalogue number C352-1903; here is negligible at this very low pressure (30 Pa), Table 1. referred to as Eccles 2; English hard paste. • A fragment of a white coffee cup with applied sprays of Prunus, made in Bow; c.1765–1770; C590-1919; Eccles Reproducibility 12; bone-ash paste. • A fruit dish in the form of a cabbage leaf decorated in Reproducibility between repeated analyses both on frac- underglaze blue made in Bow; c.1765–1770; C16-1920; tured sections and polished samples was below 0.2%. For Eccles 14; bone-ash paste. example, three consecutive analyses on different fracture • A saucer decorated in underglaze blue and enamels, areas on a sample of Dehua porcelain, gave the following made in Lowestoft; c.1770–1775; C638-1920; Eccles data for the three most abundant oxides: SiO2 73.3, 73.7, 16; bone-ash paste.

73.5%; Al2O3 19.6, 19.7, 19.8%; K2O 5.9, 5.7, 5.8%. • A fragment of a tea cup decorated in underglaze blue, made in Worcester; 1760; C591-1919; Eccles 26; soap- stone paste.

figure 5. SEM image of the Dehua porcelain samples: comparison between the fracture surface of the paste, left (lightly abraded), and polished section, right, including the surface glaze. The polished section clearly shows (by atomic number contrast) the mineral phases that form during firing of the porcelain, which do not show in the fracture section. However, the composition comparison between the two sections is similar

table 1. EDX analytical results for Dehua porcelain, reported as normalized oxide percentages as described in the text. Area analyses are typically made at a SEM image magnification of 90–350= by selecting bulk areas for analysis within these images of around 1 = 1.5 mm, down to 0.2 = 0.4 mm on associated homogeneous glazed layers

Sample Na2O MgO Al2O3 SiO2 P2O5 SO3 K2O CaO TiO2 MnO FeO SnO2 BaO PbO Paste; fractured and uncoated; average of 0.1 0.2 19.7 73.4 0.0 0.0 5.8 0.3 0.1 0.1 0.2 0.2 0.0 0.0 3 bulk analyses; 90× Paste; uncoated polished section; 30 Pa 0.1 0.2 19.0 74.2 0.1 0.1 5.7 0.2 0.0 0.0 0.2 0.1 0.1 0.0 Paste; coated polished section 0.1 0.2 19.0 74.2 0.1 0.1 5.8 0.2 0.1 0.0 0.2 0.1 0.1 0.0 (same area as above); bulk; 90× Glaze; fractured and uncoated; average of 0.2 0.8 16.0 68.6 0.4 0.1 5.6 7.2 0.0 0.3 0.2 0.5 0.2 0.0 3 bulk analyses; 100–350× Glaze; coated polished section; bulk; 90× 0.2 0.7 16.0 66.0 0.4 0.0 6.3 9.4 0.0 0.4 0.2 0.4 0.3 0.0

41 MICHELA SPATARO, NIGEL MEEKS, MAVIS BIMSON, AILEEN DAWSON AND JANET AMBERS

In all 26 bulk and spot analyses were conducted on both rendering the variation in elemental composition visible at the paste and the glaze at fractures in these objects. The high magnification. The reflected light microscopic image results obtained on the paste using the VP-SEM (Table 2) (Figure 3) is complemented by the SEM images of the crack are similar to the results published by Tite and Bimson on the side of the Virtues jar (Figures 7 and 8) that clearly on carbon-coated polished samples analysed under high show the complex layered structure above the hole. This vacuum [7; Table 1]. Most of the data are very similar, comprises the fractured paste, a crack just below the inter- except for the sample from Eccles 2, where some lead was face with the glaze (which contains gas bubbles), various detected in the glaze (3.9%) that was not detected by Tite areas of colourless or pigmented glaze and surface gilding. and Bimson, but was reported by Eccles [13; p. 23]. The The glaze was analysed by making 17 bulk analyses on other major oxides, however, such as those of aluminium, four different areas, typically at an SEM image magnifica- silicon, potassium, phosphorus and calcium, show very tion of 50–90= and by selecting bulk areas for analysis within similar results. In the present analysis, the sample from these images of between 1 = 1.5 mm and 0.2 = 0.4 mm on

Eccles 12 shows a higher percentage of Al2O3 and less SiO2 the exposed interior crack surfaces. The samples were: the than in the previous analyses by Tite and Bimson [7]. There exterior of the glaze on the curved surface near the rim (five appeared to be a small difference in the SiO2 concentration, bulk analyses); two larger colourless transparent areas (two which was around 2% less in some of the fractured samples bulk analyses); the interior of the glaze exposed in the crack/ compared to the polished samples. The reproducibility of fracture (five bulk analyses); the top of a fresh fracture on the the measurements on the fractured samples was good, so side of the vessel (one bulk analysis); and the sub-surface it might be that this variation is associated with the greater of the glaze, where it appeared to have been abraded (four porosity or roughness of these samples compared to the bulk analyses). The gilding was also studied through one more solid Dehua porcelain. bulk analysis made on an area of 0.02 = 0.02 mm at high magnification. The glaze on the curved rim is rich in silicon, aluminium and calcium, has relatively high potassium and lead, and is ANALYTICAL RESULTS FOR THE BURGHLEY low in sodium, magnesium and iron. The results from the HOUSE JARS fracture and colourless areas seem to be less homogeneous, probably due to the geometry of the areas studied; the data The Virtues jar are similar to those obtained from the rim, but with some gold content. The colourless areas show an increase in lead The SEM produces backscattered electron images (Figures and very low quantities of calcium. Lead and iron are very 5–8) that show a high degree of atomic number contrast, unevenly distributed, showing variation throughout the table 2. EDX analytical results for Eccles porcelain, reported as normalized oxide percentages as described in the text. Area analyses are typically made at a SEM image magnification of 90–150= by selecting bulk areas for analysis within these images of around 1 = 1.5 mm, down to 0.2 = 0.4 mm on associated homogeneous glazed layers

Sample Na2O MgO Al2O3 SiO2 P2O5 SO3 K2OCaOTiO2 MnO FeO CuO SnO2 Sb2O3 BaO PbO Paste; Eccles 2; 3 0.8 0.2 25.4 69.8 0.2 0.0 2.7 0.3 0.0 0.0 0.5 0.0 0.0 0.0 0.0 0.0 bulk analyses; 90= Paste; Eccles 12; 3 0.5 0.5 6.7 42.7 17.8 3.2 0.8 26.0 0.3 0.0 0.4 0.1 0.6 0.0 0.2 0.3 bulk analyses; 90= Paste; Eccles 14; 2 0.7 0.5 6.7 43.0 19.8 3.4 0.6 23.6 0.3 0.0 0.3 0.0 0.5 0.0 0.0 0.3 bulk analyses; 90= Paste; Eccles 16; 3 0.8 0.7 7.6 38.9 20.0 0.5 1.0 28.3 0.3 0.0 0.6 0.0 0.7 0.0 0.2 0.3 bulk analyses; 90= Paste; Eccles 26; 6 1.3 10.9 5.5 69.9 0.4 0.7 2.7 2.1 0.2 0.1 0.9 0.0 0.2 0.0 0.0 5.2 bulk analyses; 90= Glaze; Eccles 2; 3 1.8 2.8 17.0 63.1 0.8 0.0 3.4 3.7 0.2 0.1 1.6 0.4 0.6 0.0 0.0 5.0 bulk analyses; 90= Glaze; Eccles 12; 4 0.5 0.2 1.1 43.4 0.7 0.5 3.9 2.2 0.0 0.0 0.1 0.1 1.5 0.0 0.0 45.6 spot analyses Glaze; Eccles 12; 2 0.6 0.2 0.9 45.3 0.0 0.3 3.8 0.5 0.0 0.1 0.0 0.0 1.0 0.0 0.1 46.4 bulk analyses; 90= Glaze; Eccles 14; 3 0.5 0.2 0.8 43.1 0.3 0.0 4.0 1.2 0.0 0.1 0.3 0.2 1.7 0.0 0.0 47.6 bulk analyses; 150= Glaze; Eccles 14; 3 0.5 0.1 1.1 44.9 0.3 0.4 4.2 1.0 0.0 0.0 0.1 0.0 2.2 0.0 0.2 44.8 bulk analyses; 150=; replicate Glaze; Eccles 16; 3 0.7 0.1 1.4 44.3 0.5 0.0 3.5 2.7 0.0 0.3 0.2 0.1 0.1 0.0 0.0 46.0 bulk analyses; 90= Glaze; Eccles 26; 1.9 3.1 4.5 55.1 0.0 0.1 2.8 1.0 0.0 0.0 0.4 0.1 0.2 0.0 0.1 30.7 exterior surface; 2 bulk analyses; 90=

42 EARLY PORCELAIN IN SEVENTEENTH-CENTURY ENGLAND

figure 6. SEM image of the fracture section of one of the Eccles large figure 7. SEM image of the fractured hole seen in Figure 3, showing porcelain fragments. Note the homogeneous, fine texture of the frac- the various structures with good depth of focus. The fracture area tured paste and the lead glaze layer on the surface clearly distinguished shows the textured porcelain paste, lower centre, with the thick glaze as a lighter band due to the atomic number contrast of the lead in layer above. The smooth curved surface is the colourless glaze on the the glaze porcelain. The light surface band to the left is an area of gilding

Raman analysis identified the red pigment used in the figures on this larger vase as haematite. This was detected in the black/red interface above the wing, the dark red area of the lozenge, and the flesh colour of the putto, Figure 1. Attempts to analyse green areas on the large jar and black areas on the small jar produced only spectra for quartz

(SiO2).

The small jar

The glaze of the small jar was analysed on the rim (two bulk analyses at 150=) and on the interface between the paste and figure 8. SEM detail of the fracture on the large Burghley jar showing the glaze (one bulk analysis at 800=). The paste of the jar the textured fractured paste in the foreground, the thick glaze above was studied where the glaze was missing with three bulk with spherical gas bubbles exposed at the fracture. An interdiffusion analyses at 150=. The gilding was studied with three spot zone that is visible in the lower quarter of the glaze shows the fine analyses at 800=. texture of the crystalline minerals formed during firing and a fracture line is seen between this interdiffusion zone and the paste. Surface The glaze on the rim shows high silicon, lead and gilding is seen as the thin light surface layer. Note that there is no aluminium contents, and rather low calcium, potassium, sign of charging in this image, which was made with a SEM chamber iron and sodium. The interface between the paste and the pressure of 30 Pa glaze shows different percentages of oxides, with higher silicon, aluminium and potassium, and a lower lead content. The results for the major oxides in the paste are similar to vessel surface, Table 3. The thin glaze has rather high and those for the Virtues jar, with high silicon and aluminium variable gold content, most probably due to the dissolu- contents, but lower iron, titanium and magnesium. As tion of gold from the gilding into the glaze during the firing with the Virtues jar, lead was detected in the paste and process. The gilding composition is 98% gold and 2% silver, the gilding had been produced using almost pure gold indicating that high purity gold was applied to the surface (>94%). and fused to the glaze. Element distribution mapping was tested on the coloured The paste of the jar was analysed in the chip on the rim decoration on the small Burghley vase as a potential method (six bulk analyses) and in the crack (one representative bulk for analysing the coloured glazes or pigmented decora- area analysis on an area of 0.5 = 0.5 mm, Figure 8). The tion directly on porcelain. Figure 9 shows a false-coloured results indicate a largely homogeneous composition, rich in X-ray map for iron on the decorated shoulder of the small silicon and aluminium, low in calcium, with the potassium Burghley vase alongside an image of the vase itself. The predominant over sodium and with some magnesium, tita- iron concentration clearly follows the red-lined decora- nium and iron; lead is also present at low concentrations. tion, correlating well with the identification of haematite

43 MICHELA SPATARO, NIGEL MEEKS, MAVIS BIMSON, AILEEN DAWSON AND JANET AMBERS table 3. EDX analytical results for Burghley House porcelain jars, reported as normalized oxide percentages as described in the text. Area analyses are typically made at a SEM image magnification of 20–80= by selecting bulk areas for analysis within these images of around 1 = 1.5 mm, down to 0.2 = 0.4 mm on the exposed interior crack surfaces

Sample Na2O MgO Al2O3 SiO2 P2O5 SO3 K2O CaO TiO2 MnO FeO CuO SnO2 Sb2O3 BaO PbO Au2O3 Virtues jar; paste; 8 bulk analyses, 1.6 1.5 18.2 66.8 0.0 1.6 4.5 0.6 1.2 0.1 1.1 0.1 0.3 0.1 0.1 2.2 chipped rim 50= and fracture on side 80= Small jar; paste; 3 bulk analyses; 1.4 0.5 18.9 69.0 0.1 0.0 5.8 1.4 0.1 0.0 0.6 0.0 0.4 0.0 0.0 1.7 150= and 350= Lid; paste; 8 bulk 2.7 0.8 18.1 62.6 0.6 0.2 6.0 6.1 0.2 0.0 0.6 0.0 0.4 0.0 0.1 1.7 analyses; 60= Virtues jar; glaze on rim; 5 bulk 1.4 1.3 13.2 59.6 0.2 0.0 4.1 10.1 0.0 0.3 2.6 0.0 0.6 0.4 0.1 6.2 analyses; 50= Virtues jar; colourless glaze; 1.6 1.4 1.0 29.9 0.1 1.4 1.3 1.4 0.3 4.9 5.1 3.7 1.1 0.7 0.9 44.3 2 bulk analyses; 20= Virtues jar; glaze near fracture; 3 1.5 1.2 13.3 65.8 0.2 0.1 3.4 7.6 0.1 0.2 1.2 0.1 0.4 0.1 0.1 4.9 bulk analyses; 80= Virtues jar; thin glaze; 2 bulk 1.1 0.8 11.7 57.3 0.3 0.0 3.3 7.6 0.0 0.0 1.9 0.0 0.2 0.2 0.0 6.7 9.0 analyses; 200= Small jar; glaze; 3 bulk analyses; 1.0 0.8 11.8 53.6 0.1 0.0 3.6 4.9 0.1 0.1 1.3 0.0 0.2 0.2 0.1 22.4 150= and 350= Lid; pigmented glaze on edge of 1.5 0.8 1.4 40.0 0.0 1.1 1.8 3.7 0.1 0.2 3.5 0.3 0.4 0.0 0.0 45.5 the lid; 1 bulk analysis; 35= Lid; colourless glaze on edge of 3.1 1.4 10.6 53.4 0.3 0.8 4.5 11.5 0.0 0.2 2.1 0.0 2.6 0.6 0.3 8.5 the lid; 1 bulk analysis; 35= Lid; thin glaze under area 1.9 1.6 11.9 53.2 0.4 0.8 3.7 15.1 0.1 0.2 1.1 0.1 1.8 0.7 0.3 7.0 interface; 1 bulk analysis; 1000= as the red mineral pigment used in the coloured glaze by calcium (3.7–15%), iron (1.1–3.5%), magnesium (0.8–1.6%) Raman analysis. Presumably the red-coloured glaze mixture and sodium (1.5–3.1%). The paste has high aluminium was painted onto the white porcelain and then fired to fuse and silicon contents, is rather high in potassium, calcium the glaze. Mapping can easily be used to see the differences and sodium, and has low manganese, titanium, and iron between coloured minerals in glazes as well showing the contents. Finally, in common with the pastes of the two jars, contrast between gilding and leaded glazes compared to some lead was detected. unleaded pastes.

The lid DISCUSSION

The glaze of the lid was analysed at the interface between Some valuable results were obtained despite the use of the glaze and the paste (one bulk analysis at 1000=), on the less than ideal samples and the limited time available for transparent glaze on the edge (one bulk analysis at 35=) and analysis. A wide range of oxides was considered for these the coloured glaze on the edge (one bulk analysis at 35=). analyses, but it is clear that the two seventeenth-century The paste was analysed in two areas of the chip (three bulk jars were produced using similar raw materials, with high analyses at 60= and three spot analyses). silicon and aluminium contents, low calcium content and The results from the glazed areas gave a wide range with potassium predominant over sodium. It should be of values, particularly for the oxides of lead (7–45.5%), noted that the lid has a different composition, with higher

44 EARLY PORCELAIN IN SEVENTEENTH-CENTURY ENGLAND

free glass [7; p. 22]. In hard-paste porcelain there is no clear interface between the paste and the glaze, but in the Virtues jar a narrow inter-diffusion zone with mixed phases can be seen, Figure 8. Although the Burghley House jars have a lead glaze more characteristic of soft-paste porcelain, they are not made of soft and glassy pastes, such as those developed in France and England in the mid-eighteenth century [7; Table 2 and pp. 10–13, 14; p. 79]. In seventeenth-century London, two types of porcelain would have been available to the decorator of these jars: that imported from Dehua in China and that made by Dwight at Fulham. EDX analysis of one fragment from the production site at Dehua indicated similar concentrations of aluminium and potassium as in the Burghley House jars, but higher silicon and lower levels of iron, calcium, magnesium and sodium. Unlike oriental porcelain, which was made of so-called primary clay (china clay), Dwight’s porcelain was made using a so-called secondary clay (ball clay), with a potash frit instead of the feldspar (china stone) found in oriental porcelain. Waste fragments (wasters) excavated at Fulham figure 9. The small Burghley jar seen from above showing the red have been analysed [15], but none of these were fragments and gold decoration in the glaze. Superimposed above the image is an from smaller vessels that might resemble the Virtues jar. If analytical X-ray distribution map of iron on an area of the decoration on the shoulder, showing that the pigmented glaze corresponds to the such fragments could be studied, it would be possible to finely painted red lines on the porcelain compare the results with those from the Burghley House material. Although the Fulham fine white ware analysed by Tite contents of sodium (2.7% versus 1.6 and 1.4% for the large et al. [15; pp. 98–99 and Table 9.1], was quite variable in and small jars respectively) and calcium oxides (6.1% versus composition, it was different to the Burghley House jars, 0.6 and 1.4%), see Table 3. with a lower aluminium content and higher levels of silicon The glazes on the three objects show variable concentra- and potassium, Table 3. Furthermore, the Burghley House tions of lead, which may partly derive from the pigments, jars show higher magnesium, potassium, iron and titanium or from diffusion during firing, as lead is mobile at high contents. temperatures. This may also account for the presence of The presence of lead in the paste of both the Burghley lead in the pastes, as all three objects were coated with a House jars is difficult to explain, but it might be due to lead-rich glaze. The composition of the glaze on the lid, in contamination from the glaze since, as mentioned above, particular, varies a great deal between sampling locations. both jars have lead glazes and lead can be mobilized at high In both jars, the gilding has a very high gold content. temperatures. However, neither the Dehua porcelain (which

The thin glaze also shows significant percentages of gold, has a standard Chinese glaze of SiO2, Al2O3 and CaO) nor probably due to the dissolution of the gilding into the glaze the Fulham porcelain has lead glazes [4, 15]. during the manufacturing process. In this study, the microstructures of the fractures on both the jars and the lid showed that the porcelain bodies are clearly highly vitrified from high temperature firing and CONCLUSIONS resemble a hard-paste body, with high clay content, negligible calcium with potassium predominant over sodium Variable pressure SEM has made it possible to carry out and low, but variable, levels of titanium and iron oxides (the reliable, reproducible EDX analyses of acceptable accuracy low level of the last of these being responsible for the white- on less than ideal fractured samples, provided the usual ness of the porcelain body). The highly vitreous paste seen precautions are taken with sample geometry, the pressure in the fracture section of the Virtues jar (Figures 7 and 8) used to counteract charging is minimized to reduce skirting shows a physical texture that would indicate the presence effects and the porosity of the fractured material is low. The of crystalline phases within the glassy matrix of the paste, VP-SEM opens up new possibilities for the direct examina- compared to the smooth conchoidal fracture of the surface tion of the broken, chipped, or cracked areas that are often glaze alone. Hard-paste porcelain contains mullite crystals present on old objects; even repaired cracked vessels were (a high temperature aluminium silicate) and sometimes safe in the vacuum chamber, with no movement of glued crystals of unreacted quartz, suspended in an alkaline, lead- fragments observed.

45 MICHELA SPATARO, NIGEL MEEKS, MAVIS BIMSON, AILEEN DAWSON AND JANET AMBERS

The analyses of the Dehua and Eccles porcelains indi- thebritishmuseum.ac.uk) is an emeritus researcher and a former cate that reliable results can be obtained without invasive member of the scientific staff at the British Museum. sampling, provided that particular attention is paid to parameters such as the object geometry and the distance between the area analysed and the edge of the samples. The results from the two seventeenth-century Burghley REFERENCES House jars show that they were made of a very similar 1. Harrison-Hall, J., ‘Chinese porcelain from Jingdezhen’, in Pottery paste, suggesting that they could have been made by the in the making, ed. I. Freestone and D. Gaimster, British Museum same workshop. A paste high in aluminium and silicon Press, London (1997) 194–199. and low in calcium was used to produce the jars, and a 2. Medley, M., Yüan porcelain and stoneware, Faber and Faber, slightly different paste was used to manufacture the lid of London (1974). 3. Freestone, I.C., ‘The science of early British porcelain’, inSixth the small jar, possibly some time later. Haematite was used Conference and Exhibition of the European Ceramic Society (British to obtain the red colour of the putti and the decorations on Ceramic Proceedings 60) (2000) 19–27. the background of the large jar. In all three objects, the lead 4. Wood, N., Chinese glazes: their origins, chemistry and re-creation, content of the glaze is highly variable, perhaps because of A. & C. Black, London (1999). 5. Bimson, M., ‘The examination of ceramics by X-ray powder mixing between the glaze and the pigments during firing. diffraction’, Studies in Conservation 14 (1969) 83–89. In the large jar, it was possible to see a narrow interface 6. Kingery, W.D. and Smith, D., ‘The development of European soft- between the paste and the glaze. paste (frit) porcelain’, in Ceramics and civilisation, Vol. II, Tech- nology and style Although jars of similar size to those from Burghley , ed. W.D. Kingery, American Ceramic Society, Columbus, Ohio (1986) 273–292. House were found during the excavation of the Fulham 7. Tite, M.S. and Bimson, M., ‘A technological study of English site [16; Figure 49 and p. 71], a combination of the chem- porcelains’, Archaeometry 33 (1991) 3–27. ical compositions of both paste and glaze, and stylistic 8. Ullrich, B. and Ballmaier, H., ‘Fuldaer- und Meissner Porzellan features, suggest that the Fulham and Dehua factories were des späten 18. Jahrhunderts ein technikhistorischer Vergleich’, Beiträge zur Naturkunde von Osthessen 38 (2002) 5–13. probably not the origin of these jars. In addition, Dehua 9. Lang, G., European ceramics at Burghley House, exhibition cata- porcelain rarely lacks handles, knobs or other protrusions logue, Burghley House Preservation Trust Limited (1991). and the paste of the Dehua porcelain that was studied is 10. Wesley, M., The Buckingham jars: new evidence for the production of true porcelain in 17th century England more vitrified than the paste of the Virtues jar, Figures 5 , MA dissertation, Sothe- by’s Institute of Art (2007) (unpublished). and 8. 11. Middleton, A.P., Report on the examination of a painted and gilt jar The existence of another production centre that has not and cover, British Museum Research Laboratory Report, envelope yet been studied could be considered, as the significant 6060, The British Museum, London (1991) (unpublished). lead levels in both Burghley House jars do not correspond 12. Mathieu, C., ‘The beam-gas and signal-gas interactions in the variable pressure scanning electron microscope’, Scanning Micro- to any of the comparable results from Dehua or Fulham scopy 13(1) (1999) 23–41. porcelains. While the lead content of the paste in the 13. Eccles, H. and Rackham, B., Analysed specimens of English porce- Burghley House jars may be due to contamination from lain, Victoria and Albert Museum, London (1922). the glaze, the very presence of such a lead glaze might 14. Freestone, I.C., ‘A-marked porcelain: some recent scientific work’, English Ceramic Circle Transactions 16(1) (1996) 76–83. indicate a hitherto unknown source. 15. Tite, M.S., Bimson, M. and Freestone, I.C., ‘A technological study of Fulham stoneware’, in Proceedings of the 24th International Archaeometry Symposium, ed. J.S. Olin and M.J. Blackman, Smith- sonian Institution Press, Washington DC (1986) 95–104. 16. Green, C., John Dwight’s Fulham pottery: excavations 1971–79, ACKNOWLEDGEMENTS Archaeological Report 6, English Heritage, London (1999).

The authors are grateful to Miranda Rock, Director, Burghley House, Lincolnshire, for allowing the analyses to be carried out, and to Jon Culverhouse and Carolyn Crookall, Burghley House, for their kind assistance. Thanks are also due to Hilary Young from the Victoria NOTE and Albert Museum for the loan of Eccles collection porcelain, Peter White for the Dehua porcelain, Gordon Lang of Sotheby’s Institute of Art, Nigel Wood (University of Westminster), Bernd Ullrich (Freiburg 1. In 1991, the lid was analysed by X-ray diffraction (XRD) and University) and Caroline Cartwright of the British Museum. X-ray fluorescence (XRF) by Middleton [11]. In the paste, only quartz was identified by XRD, and potassium, iron and lead (and possibly calcium) were identified by XRF. In the glaze, potassium, calcium, manganese and lead were identified.

AUTHORS

Michela Spataro ([email protected]), Nigel Meeks ([email protected]) and Janet Ambers (jambers@ thebritishmuseum.ac.uk) are scientists in the Department of Conservation and Scientific Research. Aileen Dawson (adawson@ thebritishmuseum.ac.uk) is a curator in the Department of Prehis- tory and Europe at the British Museum. Mavis Bimson (mbimson@

46 The manufacture of a small crystal skull purported to be from ancient Mexico Margaret Sax and Nigel Meeks

Summary The small rock crystal skull (Am,St.420) was acquired by the British Museum in the 1860s and is possibly the earliest of several crystal skulls purchased by collectors in Mexico City between about 1850 and 1880, when interest in ancient Mesoamerican artefacts was high. To study the lapidary technology and authenticity of the Museum’s carving, scanning electron microscopy was used to investigate the manufacturing techniques and compare these with Mesoamerican lapidary practices in the pre-Columbian period prior to 1519. In contrast to securely dated Mesoamerican artefacts that were carved with hand-held tools, the small skull was predominantly worked with lathe-mounted rotary tools. Furthermore, the perforation had been modified and the surface appears to have been chipped deliberately, probably in imitation of antiquities recovered from burial. These observations suggest that the small crystal skull is a relatively recent piece of Mesoamerican skull art, made in post-Columbian times, between the late sixteenth century and the mid- nineteenth century when it was acquired.

INTRODUCTION Despite this, crystal skulls of various sizes that are purported to have originated from pre-Columbian Two crystal skulls were acquired by the British Museum Mesoamerican contexts have come to light in increasing during the second half of the nineteenth century. Both numbers in museum and private collections during the past are carvings of human skulls worked from single crystals century. The authenticity of the life-size British Museum of quartz (the colourless variety, rock crystal). The first to crystal skull has been the subject of increasing specula- enter the collections was a small damaged skull, 3 cm high, tion since the 1930s [5, 6]. Doubts arose concerning the with a vertical perforation, Figure 1. It had been part of the methods of manufacture and the large size of this piece Henry Christy collection and was bequeathed to the Museum because ancient Mesoamerican hard stone carvings, such by the family after Christy’s death in 1865. Three decades later as jades, were typically worked from relatively small water- in 1897, the better-known, life-size carving (c.15 cm high, worn pebbles collected from alluvial deposits using hand- 13.5 cm wide and 21 cm deep: Am1898,-.1) was purchased held tools made of natural materials such as stone, wood from the New York jewellers Tiffany and Company. Human and cane [7]. skulls worn as ornaments and displayed on racks (tzom- The life-size crystal skull was examined in the Research pantli) were known to have featured in Aztec art and Laboratory at the British Museum several times between iconography in Mexico at the time of first contact with the 1950 and 1990 and, although the evidence from the tech- Spanish in ad 1519, and both crystal skulls were registered niques then available was not totally conclusive, the carving by the Museum as ancient Mexican pieces [1–3]. The subse- was included in the exhibition Fake? The Art of Deception quent development of systematic scientific excavation in [8]. In a recent collaborative study, optical microscopy Mexico and associated studies of archaeological finds have and scanning electron microscopy (SEM) were used to shown that human skulls were sometimes carved in basalt investigate tool marks on the life-size skull and these were in bas-relief as architectural elements by Aztec and Mixtec compared with the tool marks on pre-Columbian mate- craftsmen during the post-Classic period, ad c.1200–1519, rial from secure contexts [8]. In addition, optical micro- and worked in limestone by the Maya during the earlier scopy and Raman spectroscopy were used to investigate Classic period, c.200 bc–ad 900. However, no quartz crystal solid and fluid inclusions in the quartz to provide an indi- skulls have to date been recovered from well-documented cation of its provenance. The results of these examinations archaeological excavations [4]. were supported by the findings from archival research into

47 MARGARET SAX AND NIGEL MEEKS

figure 1. Damaged rock crystal skull with a vertical perforation, Am,St.420, British Museum, c.3 cm high, 2.4 cm wide, 3.5 cm deep

the early history of the carving, and clearly demonstrated Eugène Boban, a French antiquarian, collector, dealer and that this life-size crystal skull was a product of nineteenth- enthusiastic student of ancient Mexico, between 1878 and century Europe [9]. Lathe-mounted rotary wheels had been 1881 when he was based in Paris. used to work the quartz crystal, which was obtained from Smaller crystal skulls have attracted less public atten- a source far from Mexico and ancient Mesoamerican trade tion, but their origins are of no less interest to our under- links, most probably Brazil or Madagascar. These sources standing of the past. The small British Museum crystal skull were first exploited by European merchants when the sources was considered by Walsh to be one of the “first generation of of quartz crystal in the Alps were exhausted around 1800. crystal skulls” [4]. These skulls appear to have been acquired In addition, large blocks of quartz suitable for producing in Mexico City during the second half of the nineteenth this skull were unlikely to have been available much before century by various collectors and dealers. All are perforated, the final quarter of the nineteenth century and documen- none are more than 4 cm high and the example in the British tary evidence suggests that the carving was first acquired by Museum is possibly the earliest. It was catalogued as part of

48 THE MANUFACTURE OF A SMALL CRYSTAL SKULL PURPORTED TO BE FROM ANCIENT MEXICO the original Christy collection by Steinhauer, a curator from Copenhagen, in 1862 and may have been bought by Christy (a) on a visit to Mexico City in 1856. Other small crystal skulls include two acquired by Eugène Boban when he was based in Mexico City (from 1850 to 1869) that were first exhibited at the Paris Exposition Universelle in 1867 and are currently in the collections of the Musée du Quai Branly, Paris. Another small crystal skull was bought in 1885 by the dealer William Blake from the collections of Augustin Fischer, who acted as secretary to Emperor Maximilian during the French intervention in Mexico (1863–1867); the following year Blake sold the carving to the Smithsonian Institution, Washington DC. Finally, the Museo Nacional de Mexico, Mexico City, purchased two further small crystal skulls, one in 1874 and another in 1880 [4]. These ‘first generation’ crystal skulls were acquired when interest in Mesoamerican antiquities was high. The Smithsonian curator, William Holmes, described the large quantities of ceramic, stone, wood and metal artefacts being forged or created in unknown Mesoamerican forms in 1886 in Mexico City and environs [10], while it has been suggested more recently that the first generation crystal skulls may have been reworked from pre-Columbian Mesoamerican beads in post-Columbian times [4]. Following the successful outcome of the recent study into the origin of the British Museum’s (b) life-size crystal skull, it was decided to investigate the lapidary technology of the small crystal skull (Am,St.420).

METHODS OF EXAMINATION

The fine detail preserved on the carved features of hard stone artefacts is ideal for the study of ancient lapidary technology. The use of tools and techniques can usually be recognized from the characteristic morphology of the tool marks of carved features. The approach adopted for figure2. (a) Rock crystal goblet with cup-shaped hollow base, 10.105605 the examination of the small crystal skull was similar to that Museo de las Culturas de Oaxaca, Mixtec culture, ad c.1200–1521, employed to assess the technology of the life-size crystal 8.8 cm high; (b) electron micrograph of the moulded details of the internal surface of the goblet, showing single striations in random skull. The approach, based on SEM examination of moulds of orientations that are consistent with non-rotary tools. Image: JEOL JSM carved features and their comparison with moulded exper- 840 (b) imental standards, was used by Gwinnett and Gorelick to examine the internal surfaces of ancient drill holes [11], then developed by the present authors to identify techniques of reveal original tool marks on the internal surface. The engraving on quartz cylinder seals from the ancient Middle moulds were mounted on aluminium stubs. Initially, the East [12, 13], and subsequently applied to investigate the moulds were coated with a thin layer of gold for examina- technology of jade working in China [14]. tion using secondary electron imaging in the high vacuum First, optical microscopy was used at magnifications up chamber of a JEOL JSM 840 SEM, but the recent acquisi- to 60= to survey the small skull for tool marks; features that tion of a Hitachi S-3700N variable pressure SEM (VP-SEM) appeared to bear evidence of the carving technique were permitted further moulds to be viewed without coating and selected for more detailed SEM examination. To facilitate the basically convex surfaces of the crystal skull to be exam- the examination of recessed features of interest, where ined directly at a chamber pressure of 30 Pa. The different important evidence for the carving techniques is often modes of examination are indicated in the figure captions preserved, detailed impressions were made using a dental of the SEM micrographs. silicone moulding material that posed no risk of damage Following the criteria established by the authors, the use to the skull. Prior to moulding, a thin coating of soil was of various lapidary tools and techniques was recognized by gently cleaned from the lower half of the perforation to comparing the moulded characteristics of the tool marks on

49 MARGARET SAX AND NIGEL MEEKS the skull with the moulds from features produced experi- (possibly flint) tool to saw individual beads from a pre- mentally on quartz using a range of non-rotary and rotary formed jade/green stone tube [18]. Metal lapidary tools techniques, tools and abrasive materials [15]. By consid- appear to have been introduced soon after the Spanish ering several characteristics, it is usually possible to distin- conquest, as discussed below and by Hosler [19]. guish between individual tools, for example, non-rotary Abrasive sands were sometimes applied in conjunction saws and rotary disc-shaped tools (or wheels). with the tools. In contrast to the views of Foshag [20], The evidence found on the skull was compared with who considered that the use of abrasives considerably that for pre-Columbian Mesoamerican lapidary prac- harder than quartz (Mohs’ scale of hardness, H = 7) or tices presented previously [9], and summarized below. jadeite (H = 6.5) was unlikely, Sax et al. have inferred that, The information found in Codices recording Aztec and prior to 1521, the range of abrasives may have occasion- Mixtec histories in the early colonial period, when it is ally included emery/corundum with H = 9 in addition to unlikely that traditional indigenous technologies had been quartz and almandine garnet (H = 7–7.5) [9]. significantly modified, was of particular help, as was the Rock crystal and amethyst were among the hardest SEM examination of a securely dated Mixtec rock crystal stones to have been worked in Mesoamerica. The methods goblet, Figure 2a. This goblet was recovered from Tomb 7 employed to carve these materials were documented at Monte Albán, Oaxaca, which is a Zapotec tomb that was by the Franciscan Fray Bernardino de Sahagún in the reused by Mixtecs in post-Classic times, ad c.900–1521; Florentine Codex (Book 9, Part II) between 1575 and 1577 the goblet is now in the collection of the Museo de las [21]. At that time, “a piece of metal” was used to shatter the Culturas de Oaxaca (No. 10.105605) [16]. crystals then shape selected pieces to size. Carving experiments confirmed that rock crystal and amethyst may be shaped relatively easily by chipping/pecking techniques using, for example, pointed stone or copper-based tools PRE-COLUMBIAN MESOAMERICAN LAPIDARY [15]. In a second stage of working, abrasives were used to TECHNOLOGY smooth the shaped surfaces. This was a lengthy process with the ultimate aim of providing a gleaming polish with No evidence for rotary lapidary wheels has been found in wood or cane polishers (often containing natural opaline Mesoamerica prior to the Spanish conquest. In contrast silica). to drills, which may have been hand-held, for example with a capstone and bow-driven, the use of wheels would have been dependent on devices similar in function to Observations on the Mixtec crystal goblet lathes: the attachment of a wheel to a spindle (or axle) fixed between bearings allows the tool to be rotated by Numerous tool marks are preserved on the external and some means [15, 17]. Mesoamerican lapidary methods internal surfaces of the Mixtec rock crystal goblet. Foshag were relatively simple by modern standards and relied on referred to similar marks on other Mesoamerican arte- the use of hand-held tools. These included small rigid saws facts as “ghosts” of the technique [20]. SEM observation of and broader files, pointed tools and drills made of stone or the fine detail on the goblet provided supportive evidence organic materials, such as wood and cane. for the methods of smoothing and polishing described by A painting in the Codex Mendoza (Figure 3), compiled Sahagún, although no tool marks remain on the goblet between 1541and 1542, shows an artisan using a stone from the initial stages of shaping. The moulded details of the tool marks are shown in the SEM micrograph, Figure 2b: single linear striations occur in random orientations. These irregular characteristics are consistent with a non-rotary technique of carving, involving the application of straight files in random directions. The internal concave surfaces of the goblet are occasionally characterized by single curved striations. Files with shorter working edges would have been needed to work these surfaces; the ends of straight files or files with curved working edges, similar to modern riffler files, would have been suitable. The notable, smooth shaping of the Mixtec carving is consistent with a soft tool material, such as ‘hard’ wood [15]. The variable cross-sectional thickness of the tool marks probably reflects the use of abrasive particles with figure 3. A lapidary teaching his son uses a stone tool to saw individual different grain sizes, suggesting that increasingly fine beads from a preformed perforated column (Codex Mendoza). Image: abrasives might have been applied prior to polishing. reproduced by kind permission of the Bodleian Library, Oxford Alternatively, the abrasives may have been poorly sorted

50 THE MANUFACTURE OF A SMALL CRYSTAL SKULL PURPORTED TO BE FROM ANCIENT MEXICO with a single abrasive containing grains of different sizes. and the proper left side of the cranium. Experimental Comparison of the tool marks on the goblet with those experience suggested that the profile was consistent with of experimental carvings made on rock crystal using sawing, rather than the Aztec method of pecking described files separately charged with abrasives of different hard- by Sahagún in the 1570s. It seems that subsequent working ness suggests that the marks on the goblet were made erased other tool marks produced at this stage and it was with an abrasive harder than quartz, such as almandine not possible to determine whether a thin non-rotary garnet or emery/corundum [15]. The experimental use of straight saw or a thin rotary circular had been used. quartz sand produced occasional coarse, often non-linear Particularly well-defined linear tool marks remain striations, and continued filing gave shorter, finer linear from a subsequent stage of shaping, apparently unmodi- striations, unlike those on the goblet. Durán, a sixteenth- fied by subsequent smoothing prior to polishing. They century priest, recorded that during the rule of Moctezuma are preserved on a narrow surface (c.1.5 mm wide and (1502–1520), the Aztecs obtained lapidary sands from the 8 mm long) under the zygomatic bone, protruding from Mixtec provinces of Quetzaltepec and Tototepec, now in the proper right-hand side of the carving above the jaw, Oaxaca [22]. Although the mineralogy of these sands is Figure 1. In the SEM micrograph in Figure 4a, a mould not known, sources of almandine garnet are found at San Sebastián Abasolo, Oaxaca [23], and sources of emery/ corundum occur in Oaxaca and neighbouring Guerrero and Puebla [24]. The tool marks are recessed in the goblet and protrude upwards on the mould (Figure 2b), showing rough and unpolished surfaces that contrast with the remaining smooth and highly polished surfaces of the goblet. The combination of the two textures gives the artefact a softly polished overall appearance. Furthermore, as noted by Foshag [20] and Chenault [25], unpolished recesses are diagnostic of rigid polishing tools, such as the wood and cane polishers described by Sahagún [21]. Unlike soft felt or leather-covered tools charged with fine-grained polishing mixes in post-conquest times, rigid polishers would not have reached the recessed surfaces. It is against these Mesoamerican methods used in pre-Columbian times that the carving of the skull may be judged.

LAPIDARY TECHNOLOGY OF THE SMALL SKULL

The sides of the small crystal skull have a matt, apparently worn finish and parts of the carving are damaged: several surfaces are chipped and the lower jaw (mandible) is missing, Figure 1. Numerous tool marks are preserved within the polished surfaces as ‘ghosts’ of the technique [20]. Their characteristics provide evidence for several stages of working. The ways in which the various techniques and tools are recognized are described and illustrated below in the possible sequence of their application; the characteristics of the chipped surfaces are also discussed. figure 4. SEM images of moulds of carved features in the small crystal skull – in these oblique views, the recessed features on artefacts protrude Shaping upwards on the moulds (across the images): (a) the surface of the zygomatic bone at the side of the skull – the profiles and striations along the ends of cuts (for example, arrowed) are slightly convex, reflecting An early stage of working appears to have been to saw their concave depth in the skull, consistent with the use of a grinding flat surfaces at opposite sides of the quartz crystal. Using wheel (see text); (b) experimental feature produced by wheel-cutting, for comparison with (a) and (c); and (c) the nasal apertures indicate the the VP-SEM to examine the skull directly, a well-defined use of a smaller engraving wheel c.15 mm diameter. Images: Hitachi S- linear profile was seen along the join of the upper surface 3700N (a) and JEOL JSM 840 (b) and (c)

51 MARGARET SAX AND NIGEL MEEKS of the underside surface is inverted. This oblique view of the mould shows a series of carved features protruding upwards across the image: a slight convex curvature is seen along the ends of individual features, for example, the feature at the bottom left indicated with an arrow. The moulded profiles reflect the slight concave depth of the features in the skull. Pronounced regular continuous parallel striations are present along each feature. These characteristics are consistent with the use of a rotary wheel. Similar features were produced experimentally on rock crystal using a metal disc-shaped wheel, charged with a loose abrasive mix such as emery/corundum, Figure 4b. The quartz was held in a stationary position against the rim of a rotating wheel mounted on the spindle of an electrically driven lathe [15]. Experimental experience suggested that in shaping the recess under the zygomatic bone, the small quartz crystal blank was repeatedly held in different, more or less stationary positions against a grinding wheel with a relatively large diameter. A similar approach appeared to have been used to shape other parts figure 5. Composite SEM image of a mould of the lower half of the Smoothing perforation in the crystal skull. First, the pronounced circumferential of the skull, such as the cranium (see below). striations (indicated) were produced with a solid drill and a hard abra- Large diameter wheels offered the benefit of a fast rim sive then, in a second stage of working, the surfaces were smoothed speed for a given rotational speed of the shaft. to resemble those of pre-Columbian Mesoamerican artefacts. Image: Less pronounced and continuous striations are present Hitachi S-3700N on other parts of the skull that have a shallow concave depth, such as the canine fossae above the teeth. Carving tests showed that similar striations were produced on quartz when the material was moved against the rim of the defined characteristics of the first drill were largely erased; rotating wheel, rather than being held in a stationary posi- see the lower half of Figure 5. Faint longitudinal striations tion as described above [15]. The use of lathe-mounted on the mould showed that the perforation was smoothed rotary tools for shaping the small skull contrasts with by filing, using a tool or an abrasive material of similar traditional Mesoamerican methods of pecking. hardness to quartz. The fine detail in the hemispherical recesses forming the eye sockets (8 mm diameter) provided further insight into Perforating and shaping eye sockets the rotary tool used to shape and/or smooth these features. Groups of fine parallel striations indicated that the head of Previous investigations showed that circular features, the tool had a curved working edge and was charged with such as the perforation and eye sockets in the skull, were an abrasive. These groups of striations occurred in various produced by drilling [15]. The perforation, visible through orientations. Circumferential striations were produced the quartz crystal, was made by drilling two holes from the using the tool in ‘drill’ mode, rotating about an axis essen- cranium and the base in the area of the foramen magnum tially perpendicular to the facial features, while tangential to meet more or less centrally. Examination of the moulded striations were produced using the tool in ‘wheel’ mode, details of the cleaned, lower half of the perforation rotating about an axis essentially parallel to the facial (c.10 mm long) revealed two stages of working. Traces features. The use of the tool in both drill and wheel modes of the tool marks produced during the first stage were suggested that it was lathe-mounted. In contrast to hand- preserved towards the end of the moulded hole, adjacent held drills, lathe-mounted tools such as spherical ‘burrs’ to the central join and visible in the upper half of Figure may easily be used in both drill and wheel modes. 5. The tapered profiles here were consistent with a solid drill, c.2.5 mm diameter. The well-defined pronounced circumferential striations showed that an abrasive was Smoothing used with the drill. Comparison of the striations with those produced experimentally on quartz with stone or In contrast to the curved sides of the Mixtec goblet (Figure metal drills charged with a range of abrasives indicated 2a), which are evenly shaped and were painstakingly that an abrasive considerably harder than quartz, probably smoothed with hand-held files and abrasives, the convex emery/corundum, was used with a metal drill [11, 15]. surfaces of the skull, particularly those of the cranium, Elsewhere, the walls of the hole are predominantly were not fully smoothed prior to polishing and have a smoother as, in a second stage of working, the well- faceted appearance, Figure 6. The surfaces of the facets

52 THE MANUFACTURE OF A SMALL CRYSTAL SKULL PURPORTED TO BE FROM ANCIENT MEXICO

Polishing

SEM observations of moulded surfaces at magnifications up to 100= show that the polish extends into the recessed tool marks and the sides, and occasionally the base of engraved features. As noted above, polished recesses are diagnostic of relatively soft polishing tools, such as the felt- or leather- covered wheels charged with fine polishing mixes in post-conquest times. The rigid polishing tools used in pre- Columbian times would not have reached these recessed surfaces.

figure 6. SEM image of the crystal skull showing the faceted upper surface of the cranium and details of two engraved sutures. The ridge (arrowed) along the sutures is consistent Secondary chipping with the use of a worn wheel while breaks in their continuity (one is arrowed) reflect pauses in wheel-cutting. Image: Hitachi The base of the mandible (16 mm deep) is characterized by S-3700N large conchoidal fractures, Figure 7. These are not typical of normal handling wear and appear instead to have been worked by indirect percussion using manual tools [15]. were flat or slightly concave and retained extensive traces Experiments to chip/peck rock crystal suggest that a suit- of the abrasive striations produced by the grinding wheel ably hard and tough pointed tool or chisel was held in (see Shaping above). several positions around the teeth and struck firmly with a hammer. Furthermore, the outer edge of the base is char-

Engraving

Engraved details comprise three long narrow features (less than 0.5 mm wide) cut into the cranium to imitate sutures between the plates of an immature human skull (Figure 6), narrow features representing teeth and the upper lip, and wider (c.1.3 mm) features indicating nasal apertures, Figure 1. The features are curved or linear and fine, parallel striations are present along their length. In an oblique view of a mould of the nasal apertures (Figure 4c), the two features are seen across the image, their convex profiles on the mould reflecting their concave depth in the artefact. These engraved features have very similar characteristics to those produced experimentally using wheels (Figure 4b), as described above under Shaping. The curvature of the moulded nasal apertures (Figure 4c) indicates this wheel had a diameter of about 15 mm. Further observations provide a fuller description of workshop practices. First, the surfaces of the sutures, upper lip and teeth are characterized not only by fine longitudinal striations but also by a pronounced continuous ridge (arrowed in Figure 6), apparently consistent with the use of a worn engraving wheel [26]. The defect was not present on the thicker wheel employed for working the nasal apertures. Second, frequent breaks in the shape and depth at intervals of 1–7 mm along the length of longer features (a break is arrowed in Figure 6), may indicate separate appli- cations of the crystal surface to the wheel. An alternative explanation is that the wheel may have been mounted on the spindle of a lathe driven in a reciprocal motion with, figure 7. SEM image of the base of the jaw of the crystal skull showing a surface characterized by large conchoidal fractures and smaller cavi- for example, a simple bow or foot treadle. ties (arrowed) around the edge. These are not typical of normal handling wear, appearing instead to have been worked by indirect percussion using manual tools. Image: Hitachi S-3700N

53 MARGARET SAX AND NIGEL MEEKS acterized by fine conchoidal and angular cavities (arrowed excavated at the Olmec site of La Venta, Tabasco (1000–600 in Figure 7), consistent with systematic pecking. Numerous bc), in the collections of the Smithsonian Institution [27, conchoidal and angular cavities, for example on the zygo- 28]. In addition, the external surfaces of the crystal skull matic bones at opposite sides of the skull and around the were deliberately chipped, presumably in imitation of exca- nasal bone (Figure 4c), also appear to have been deliberately vated antiquities. In 1886, William Holmes described the created with tools. SEM observation of the moulded inter- manufacture of large quantities of spurious antiquities in faces between conchoidal fractures and adjacent features Mexico City, where the British Museum crystal skull and shows that surfaces were chipped mainly after the skull had other small crystal skulls were acquired by various collec- been carved and polished. tors during the second half of the nineteenth century. The present investigation and the earlier programme of research show that the two purportedly ancient Mexican crystal skulls in the British Museum are both of more recent DISCUSSION origin [9]. The place and purpose of their manufacture differ however. The small skull was probably made in Mexico City to Lathe-mounted rotary tools were used extensively in the satisfy a demand there for antiquities, while archival research manufacture of the small crystal skull: large diameter by Walsh suggests that the large skull was worked in Europe grinding wheels were used for shaping surfaces, smaller [4,9], apparently as an objet d’art. The earliest extant reference diameter wheels were used for engraving features and a to the life-size carving is in Eugène Boban’s 1881 Paris sale spherical tool similar to a modern burr was employed catalogue, which provided no details of provenance or date, for working the eye sockets. These tools were apparently but described the crystal skull as a “chef-d’oeuvre de l’art du metal and charged with an abrasive considerably harder lapidair” [29]. Likewise, four years later in 1885, when the than quartz, probably emery/corundum. Evidence was piece was displayed by Boban alongside human skulls from also found for the use of rotary polishing tools. To date, no Mexico and other parts of the world in his shop, the Museo evidence has been found in pre-Columbian Mesoamerica Cientifico, in Mexico City, no details of provenance or date for lathe-mounted or metal lapidary tools or the regular were given and the crystal skull was termed a “pieza unica use of abrasives as hard as emery/corundum, as illustrated en el mundo” [9]. Later that year, having failed to sell the by the working of the Mixtec crystal goblet excavated at carving, Boban approached the Museo Nacional de Mexico, Monte Albán. These innovations appear to have been Euro- describing the life-size crystal skull as an ancient Mexican pean introductions in post-Columbian times, after 1519. artefact for the first time. Although Sahagún documented the use of metal tools between 1575 and 1577 [21], no mention was made of lathe- mounted rotary wheels, which appear to have been introduced sometime after 1577. CONCLUSIONS The perforation in the crystal skull was drilled with a metal tool and a hard abrasive, probably emery/corundum, The SEM investigation of lapidary technology indicates rather than one of the natural tool materials and soft abra- that the small perforated crystal skull in the collections of sives generally employed prior to 1519, indicating that the British Museum is not ancient Mexican and was made the possibility that the piece was worked from a large pre- at some time after the late sixteenth century, using rotary Columbian Mesoamerican rock crystal bead should also be tools unavailable in pre-Columbian Mexico. No quartz discounted. crystal skulls are known from official excavations in Mesoa- The lack of smoothing on the faceted surfaces of the merica and the carving appears to be a more recent repre- crystal skull, and the use of a worn engraving wheel attest sentative of Mexican skull art. The crystal skull was acquired to a cursory approach within the workshop. Furthermore, by Henry Christy sometime before 1862 and is thought to modifications to the carved features suggest that the crystal have been bought by him in 1856 on a visit to Mexico City, skull may have been produced in imitation of a Mesoamer- where spurious Mesoamerican antiquities were manufac- ican artefact. After drilling, the walls at both ends of the tured. This suggests that the crystal skull is probably of mid- perforation were smoothed and a thin, even layer of soil nineteenth century origin. It is hoped that ongoing investiga- applied. Although perforations in pendants were commonly tion of the mineralogy of the quartz will provide an indication smoothed by secondary working to prevent the chafing of of the provenance of the rock crystal used for the carving. a suspension cord, this seems unlikely in the case of the crystal skull as the surface of the narrow central join between the two halves of the perforation remains unmodified by secondary working, Figure 5. Instead, it is notable that ACKNOWLEDGEMENTS the smooth surfaces, which were visible under the coating of soil at both ends of the perforation, resemble those of The authors are most grateful to Arturo Olivéros, who as director of excavations in Oaxaca in the 1990s, brought the Mixtec goblet to perforations of comparable dimensions in securely dated London for examination, and Jane Walsh at the National Museum of Mesoamerican quartz and jade carvings, such as the tubes Natural History, Smithsonian Institution, for contributing to the study.

54 THE MANUFACTURE OF A SMALL CRYSTAL SKULL PURPORTED TO BE FROM ANCIENT MEXICO

Thanks are also due to colleagues and former colleagues at the British 11. Gwinnett, A.J. and Gorelick, L., ‘The change from stone drills to Museum: Elizabeth Carmichael for her role in initiating the study; copper drills in Mesopotamia’, Expedition 29 (1987) 15–24. Colin McEwan and Andrew Middleton for advice on the text; and 12. Sax, M. and Meeks, N.D., ‘Methods of engraving Mesopotamian Antony Simpson for processing the images. quartz cylinder seals’, Archaeometry 37 (1995) 25–36. 13. Sax, M., Meeks, N.D. and Collon, D., ‘The introduction of the lapidary engraving wheel in Mesopotamia’, Antiquity 74 (2000) 380–387. 14. Sax, M., Meeks, N.D., Michaelson, C. and Middleton, A.P., ‘The AUTHORS identification of carving techniques on Chinese jade’,Journal of Archaeological Science 31 (2004) 1413–1428. Margaret Sax ([email protected]) and Nigel Meeks 15. Sax, M., McNabb, J. and Meeks, N.D., ‘Methods of engraving ([email protected]) are scientists in the Department Mesopotamian cylinder seals: experimental confirmation’,Archae- of Conservation and Scientific Research at the British Museum. ometry 40 (1998) 1–21. 16. Caso, A., ‘El Tesoro de Monte Albán’, Memorias del Instituto Nacional de Antropologia e Historia 3 (1969). 17. Di Castro, A., ‘Los bloques de ilmenita de San Lorenzo’, in Pobla- cion Subsistencia y Medio Ambiente en San Lorenzo Tenochtitlán, REFERENCES ed. A. Cyphers, Universidad Nacional Autónoma de México, Mexico (1997). 1. Carmichael, E., Turquoise mosaics from Mexico, Trustees of the 18. Codex Mendoza, vol. III (1541–1542), translated and ed. J.C. British Museum, London (1970). Clark, Waterlow and Sons, London (1938) 70. 2. McEwan, C., Middleton, A.P., Cartwright, C.R. and Stacey, R.J., 19. Hosler, D., The sounds and colors of power: the sacred metallurgical Turquoise mosaics from Mexico, British Museum Press, London technology of ancient West Mexico, MIT Press, Cambridge (1994). (2006). 20. Foshag, W.F., ‘Mineralogical studies on Guatemalan jade’, in Smith- 3. McEwan, C., Stacey, R.J. and Cartwright, C.R., ‘The “Tezcatlipoca” sonian Miscellaneous Collections 135(5), Washington DC (1957). skull mosaic in the British Museum collections: new insights 21. Sahagún, B. de, Florentine Codex: general history of the things and questions of identity’, in Texcatlipoca: trickster and supreme of New Spain (1575–1577), translated and ed. C.E. Dibble and Aztec deity, ed. E. Baquedano, University of Colorado Press A.J.O. Anderson, School of American Research and University of (forthcoming). Utah, Santa Fe (1950–1982). 4. Walsh, J.M., ‘Legends of the crystal skulls: why Indiana Jones 22. Durán, F.D., The history of the Indies of New Spain (1581), trans- might want to rethink his latest quest’, Archaeology Magazine lated and ed. D. Heydon, University of Oklahoma Press, Norman 61(3) (2008) 36–41. (1994). 5. Morant, G.M., ‘A morphological comparison of two crystal skulls’, 23. Panczer, W.D., Minerals of Mexico, Van Nostrand Reinhold, Man XXXVI (1936) 105–107. New York (1987). 6. Digby, A., ‘Comments on the morphological comparison of two 24. Langenscheidt, A., ‘Los abrasivos en Mesoamérica’, Arqueología crystal skulls’, Man XXXVI (1936) 107–109. Mexicana XIV(80) (2006) 55–60. 7. Kidder, A.V., Jennings, J.D. and Shook, E.M., Excavations at Kami- 25. Chenault, M.L., Technical analysis of Precolumbian Costa Rican naljuyu, Guatemala. With technological notes by A.O. Shepard, Publi- jadeite and greenstone artefacts, Master of Arts thesis, Depart- cation 561, Carnegie Institution, Washington DC (1946) 104–124. ment of Anthropology, University of Colorado, Boulder (1986) 8. Jones, M., ‘The limits of expertise’, inFake? The art of deception, ed. (unpublished). M. Jones, P. Craddock and N. Barker, British Museum Publications, 26. Sinkankas, J., Gem cutting: a lapidary’s manual, 3rd edn, Van London (1990) 291–307. Nostrand Reinhold, New York (1984) 46–48. 9. Sax, M., Walsh, J.M., Freestone, I.C., Rankin, A.H. and Meeks, 27. Drucker, P., La Venta, Tabasco: a study of Olmec ceramics and art N.D., ‘The origins of two purportedly pre-Columbian Mexican in Smithsonian Institution Bureau of Ethnology, Bulletin 153, US crystal skulls’, Journal of Archaeological Science 35 (2008) Government Printing Office, Washington DC (1952) 172–173. 2751–2760. 28. Sax, M. and Walsh, J.M., ‘SEM examination of artefacts recovered 10. Holmes W.C., ‘On some spurious Mexican antiquities and their rela- from La Venta, Tres Zappotes and Las Tuxtlas’ (in preparation). tion to ancient art’, Annual Report for 1886, Smithsonian Institution, 29. Walsh, J.M., National Museum of Natural History, Smithsonian Smithsonian Institution, Washington DC (1889) 319–334. Institution, personal communication, 2009.

55 Assyrian colours: pigments on a neo-Assyrian relief of a parade horse Giovanni Verri, Paul Collins, Janet Ambers, Tracey Sweek and St John Simpson

Summary The colours present on a fragment of a neo-Assyrian carved stone relief (British Museum 1847,0702.27: ME 118831) depicting a parade horse, which retains extensive evidence of original polychromy, were investigated using visible-induced luminescence imaging and Raman spectroscopy. The horse harness was found to have been extensively painted with elaborate patterns including alternating bands of Egyptian blue and red ochre, two pigments commonly encountered in contemporary contexts. Although the blue pigment is still visible in some areas of the relief, its overall distribution across the object is obscured by surface dirt and/or the degradation products from the original materials. However, even in discoloured areas, the spatial distribution of the pigment was revealed by illuminating the object with visible light and by recording the luminescence of Egyptian blue in the infrared range (c.800–1000 nm). This non-invasive technique allowed the spatial distribution of Egyptian blue to be mapped thoroughly and rapidly. The survival of some of the original polychromy on the relief poses constraints on its cleaning and raises questions about the survival of these and other pigments on Assyrian (and other) sculptures. However, the comparison of the distribution of pigments on this relief with that on contemporary Assyrian wall paintings from Til Barsib is highly instructive, as it confirms for the first time that similar colour schemes were used on reliefs and wall paintings.

INTRODUCTION or a simple compound produced synthetically. The organic binders available included gums, egg, milk or glues derived Although many ancient civilizations are known to have made from animal sources. Metal adornments, such as gilding and extensive use of polychromy on sculpture and carved stone, silvering, were also commonly used on ancient sculpture; much of this colour has since been lost. This is particularly often the only surviving traces of these are the means by evident when direct comparisons can be made between which they were attached [1]. Although organic materials, wall paintings and ceramics, which often remain brightly particularly the binders, but also the organic colorants, are decorated, and sculpture from the same period, which is highly susceptible to decay, paint often survives surpris- frequently denuded of virtually all colour [1]. For example, ingly well in stable burial conditions. As described here, although classical sculpture has been prized for centuries for drawings and watercolour illustrations of objects made at its pure whiteness, it has been recognized that ancient Greek the time of excavation clearly show newly excavated carved and Roman stone artefacts were often originally brightly stone pieces with obvious traces of polychromy that are no coloured [1, 2]. Similarly, pigments such as Egyptian blue, longer visible on the same objects. Much of the difference malachite and vermilion have been identified on external between colour survival on carved stone and that on wall limestone reliefs and tomb façades at the Achaemenid sites painting and ceramics may be explained by a combination of Persepolis and Naqsh-e Rustam [3, 4]. There are a number of the highly destructive effects of an unstable environment of possible reasons for the loss of the original polychromy. on freshly excavated materials and the conditions prevailing The paints used in antiquity would generally have comprised during their subsequent display and storage. However, two components: a coloured pigment and an organic binder. the main culprits, for classical sculptures at least, seem to The pigment would have either been based on an organic be the over-zealous cleaning procedures that have been material derived from a plant or animal extract or an inor- undertaken for centuries, often for aesthetic reasons. These ganic pigment that comprised a naturally occurring mineral aggressive cleaning practices can be traced back at least as

57 GIOVANNI VERRI, PAUL COLLINS, JANET AMBERS, TRACEY SWEEK AND ST JOHN SIMPSON far as the rediscovery of ancient Roman sculpture during the Henry Layard’s excavations at Nimrud and were displayed Renaissance. Although scattered traces of polychromy must from 1852 to 1964 on the east side of the Assyrian Tran- have been present on newly excavated ancient sculptures, sept. While in this location, they were described in the 1884 their general white appearance determined the beginning Guide to the Exhibition Galleries as “chiefly fragmentary of a new fashion that highly valued the colour of bare stone. figures from a more extensive series, some on a large scale, Later, the paradigmatic white of neo-classicism influenced and retaining remains of colour. The horses’ heads, facing cleaning regimes and these were even extended to objects the window, are richly and carefully finished” [6]. Between from other ancient cultures. Another factor that may have 1928 and 1935 the Oriental Institute of the University of contributed to pigment loss was overenthusiastic moulding Chicago undertook extensive excavations at Khorsabad, in for the purposes of creating casts, whether for academic, the process of which room VII was re-examined and the display or purely commercial reasons. surviving panels removed to Chicago [7]. Scientific examination of ancient artefacts may reveal Although surviving colours are sparse and our present the presence of original materials and may shed light on understanding of painting schemes on Assyrian reliefs is painting practices in antiquity. In particular, imaging tech- limited, it is generally agreed that many Assyrian reliefs niques are useful to characterize the spatial distribution of were originally painted, either over their entire surface or, the remaining traces of painting materials within a painted perhaps more often, in specific areas [3]. Indeed, remains of scheme [1]. Such imaging techniques, the selection of which some colour are known to have been visible on the panels depends on the physical and chemical properties of the from room VII when they were first excavated; Flandin compounds under investigation, generally include visible, records the presence of red, black and blue, the last colour infrared (IR), ultraviolet and photo-induced luminescence. used on birds and fir trees. He makes no reference to paint A particular photo-induced luminescence imaging tech- on the horse discussed here, although colours must have nique, visible-induced luminescence (VIL), plays a key role been apparent, as traces of red and blue are still visible to in the characterization of one very common ancient pigment the naked eye. – Egyptian blue. This contribution discusses the analysis of a neo-Assyrian relief using VIL imaging and Raman spectroscopy.

THE RELIEF

The sculpted gypsum head of a caparisoned horse (British Museum 1847,0702.27: ME 118831) comes from the palace of the neo-Assyrian king Sargon II (reigned 721–705 bc) at Khorsabad, ancient Dur Sharrukin, in northern Iraq. Sargon founded Khorsabad in 717 bc but construction at the site was halted in 705 bc when the king was killed in battle and his successor Sennacherib (704–681 bc) moved the capital to Nineveh. In the tradition of some earlier Assyrian royal builders, Sargon had the lower walls of the principal rooms and courtyards in his palace decorated with carved slabs of gypsum. The sculpture considered here was originally part of a narrative frieze, a hunting scene, which adorned a small room in the north west wing of the palace, perhaps the private quarters of the king. The slabs of gypsum are divided into three horizontal registers. The top register depicts a banquet and was divided from the hunting scene in the lower register by a wide band of inscription. French excavations of 1842–1844 had uncovered the room (numbered as VII), and the surviving reliefs were recorded in excellent drawings by Eugène Flandin, Figure 1 [5; Plate 109]. In 1845, Alexander Hector, a merchant who had settled in Baghdad, visited Khorsabad and removed some reliefs and carved inscriptions from various areas of the palace. The British Museum figure 1. Drawing by Eugène Flandin of a relief representing a hunting scene from the palace of the neo-Assyrian king Sargon II (721–705 bc) purchased 50 of these fragments, including this head of a at Khorsabad. Drawn during a French excavation in 1842–1844 before horse, from Hector in 1847; they entered the collections only the reliefs were fragmented. The box outlines the original position of a few weeks after the arrival of the first Assyrian reliefs from the head of the caparisoned horse now in the British Museum

58 ASSYRIAN COLOURS: PIGMENTS ON A NEO-ASSYRIAN RELIEF OF A PARADE HORSE

METHODOLOGY Technical examination of the relief

VIL imaging of Egyptian blue The relief was first examined closely with the aid of low magnification. It was then imaged in visible-reflected and Much of the work described here was only possible because VIL modes. Based on the data from the visual examination of a relatively new imaging technique for the study of and the VIL images, small samples (of one or two grains) Egyptian blue, which has been developed at the British of each pigment present were then taken and analysed Museum and the Courtauld Institute of Art, London using Raman spectroscopy as detailed in the experimental [8–10]. Since it is of such importance to the interpretation appendix. of this object, and of great potential use in similar studies, the technique is briefly described here; full details of the experimental procedure are included in the experimental appendix. RESULTS AND DISCUSSION Egyptian blue – one of the earliest synthetic pigments

– is a calcium copper tetrasilicate (CaCuSi4O10) that has Figure 2a shows the current appearance of the relief. the same composition and structure as the rare natural Despite the presence of surface dirt, traces of blue and red mineral cuprorivaite. This bright blue inorganic compound pigments can be observed in several locations, such as the was extensively used throughout the Mediterranean from tassel strapped on the horse’s neck and the elaborate feath- the Fourth Dynasty in Egypt (c.2500 bc) until the end of ered decoration on the headstall of the animal. A brown the Roman period in Europe [11]. When excited by radia- coloration is also present over much of the object. This tion in the blue, green or red region of the electromag- brown material seems to be composed of a homogeneous netic spectrum, Egyptian blue shows an intense and broad patina and dirt that has accumulated on the surface. There emission (full width at half peak height of c.120 nm) in is also a small splash of bright red paint on the mane, which the IR region, centred at about 910 nm [12, 13]. The emis- has a different hue to the red on the tassels and proved to sion from Egyptian blue can be recorded by using visible be of modern origin (see below). excitation sources and a camera with some sensitivity to Attempts to determine the original distribution of the IR radiation in the c.800–1000 nm range of the electro- red and blue pigments were complicated by the dirt, the magnetic spectrum. Commercially available fluorescent brown coating and the discontinuous distribution of the lamps, which were used as light sources in this study, emit surviving pigments. In Figure 3a, a detail from the relief, mainly visible radiation with only a small component the present distribution of the red and blue particles can of IR radiation. In the monochrome VIL images, Egyp- be seen. Figures 2b and 3b, the VIL images of the relief tian blue appears as ‘bright white’, while all other mate- and corresponding detail, give far better impressions of rials appear grey. Grey levels higher than those for a 99% the distribution of the blue pigment. In these images the reflectance standard, which is placed alongside the object bright white areas correspond to the presence of Egyptian under investigation and included in the image, can only be blue. Since even single particles of the blue pigment can due to luminescence from the Egyptian blue. Grey levels be revealed using this method, it is possible to define its less than the reference standard are considered to result distribution within the scheme of the composition very from reflected ‘stray’ IR radiation. The presence of a low clearly. Unfortunately, no analogous method currently level of stray IR radiation from the fluorescent lamps is, in exists for mapping the red pigment, so its distribution this instance, considered beneficial, as it allows the loca- must be extrapolated from visual examination. tion of the fluorescing materials to be correlated with the Raman analysis confirmed the blue pigment to be scheme of the work of art. Light-emitting diodes (LED), Egyptian blue, and showed the red to be mostly haema- which emit no stray IR radiation, were also used in this tite (Fe2O3), probably representing the use of natural red study [10]. ochre. Both pigments were in common use throughout In summary, this technique allows an image to be the ancient world at this period and have been recorded produced in which every region containing Egyptian from other Assyrian and later Achaemenid contexts blue, even down to single crystals in some instances, is [3, 4]. The bright red paint splash on the mane was found clearly visible as a ‘bright white’ area simply by illumi- to be lead chromate, confirming it to be modern contami- nating an object with fluorescent lamps in an otherwise nation, almost certainly from nineteenth- or twentieth- darkened room and using an adapted digital camera. It century cataloguing of the object; the same paint was should be mentioned that, although other pigments, such used to add the accession number at the top right of the as cadmium red and yellow, show luminescence properties relief. The Raman analysis of the brown material did not in the same spectral range, the experimental configuration provide conclusive results, but Fourier transform infrared used in this study is only sensitive to Egyptian blue and the spectroscopy suggests the presence of copper oxalate. chemically related Chinese pigments Han blue and Han Although this may represent the degraded remains of an purple. original organic binder, it could also result from relatively recent surface treatment or exposure to the elements.

59 GIOVANNI VERRI, PAUL COLLINS, JANET AMBERS, TRACEY SWEEK AND ST JOHN SIMPSON

figure 2. Head of the caparisoned horse (British Museum 1847,0702.27: ME 118831): (a) visible image, in which remnants of blue and red pigments can be observed; (b) VIL image showing the particles of Egyptian blue as ‘bright white’ areas

figure 3. Detail of the horse shown in Figure 2, showing the surviving polychromy on the tassel: (a) visible images; (b) VIL image of the same detail, showing the ‘bright white’ areas that correspond to the presence of Egyptian blue and confirm its original use in alternating red and blue stripes. Note the single brush strokes and spattered paint containing particles of Egyptian blue

The alternating red and blue pattern of colour deco- 1929 and 1931 [14]. Wall paintings, mostly polychrome on rating the horse’s head, the tassel and the trappings finds white lime plaster, were discovered in situ in one area of its closest parallel in a wall painting from an Assyrian royal the building identified as the royal apartments. Some frag- residence at Til Barsip (modern Tell ‘Ahmar). Located on ments of the paintings are housed in the Musée du Louvre the west bank of the River Euphrates in modern Syria, Til and Aleppo Museum, but they are known principally from Barsip was excavated by French archaeologists between careful colour scale copies made soon after their discovery

60 ASSYRIAN COLOURS: PIGMENTS ON A NEO-ASSYRIAN RELIEF OF A PARADE HORSE by the architect Lucien Cavro, many of which have been painted applying strokes of haematite over Egyptian blue, published by Parrot [15]. The relevant painting was uncov- while the middle section was painted using Egyptian blue ered in room XXIV; it is a large composition, some 22 over haematite. The blue strokes can be clearly observed in metres long by 1.5 metres high, painted at eye level, above a the middle section. band of bitumen that lined the base of the wall. The French This combination of colours is familiar in elite jewellery excavators dated it to the time of Tiglath-pileser III (reigned from ancient Mesopotamia: red cornelian and blue lapis 744–727 bc), although a recent study of the textile patterns lazuli were among the most popular ornamental stones in the scene by Albenda has led her to date the painting used for beads, most famously in the ‘Royal Graves’ at Ur convincingly to the reign of Sargon II [16; pp. 69–74]. The (c.2500 bc) and the same colour symbolism extends back painting depicts an enthroned Assyrian king, approached into deeper antiquity, judging from personal ornaments by tribute bearers or prisoners of war. Behind the king stand excavated in sixth-millennium bc graves at Tell es-Sawwan officials, a chariot and two spare horses. The leading horse [17, 18]. In Mesopotamia these rare imported stones were is coloured blue (Figure 4) [15], while its trappings and the synonymous with splendour and were attributes of gods and tassel, like those of the Khorsabad horse, are decorated in heroes; they were believed to possess healing properties and a pattern of alternating red and blue stripes. These stripes were placed in the foundations of buildings for ceremonial on the tassel of the Khorsabad horse can be better observed or magical reasons. In addition, monumental architecture in the VIL image of the detail, Figure 3b. In this case, could be decorated with the same colours, perhaps to provide the red stripes appear dark, while the blue stripes appear magical protection; at Nineveh, for example, the battlements bright white. The top and bottom sections of the tassel were were striped red, blue and white (unpainted) [19].

CONCLUSIONS AND FURTHER INVESTIGATIONS

The combined use of VIL imaging and Raman spectroscopy allowed the identity and distribution of the original colours on a neo-Assyrian relief to be determined. Egyptian blue and haematite were identified on a sculpted gypsum head of a caparisoned horse excavated from the palace of the neo-Assyrian king Sargon II (reigned 721–705 bc) at Khorsabad, ancient Dur Sharrukin, in northern Iraq. The painted scheme on the relief was found to be nearly identical to contemporary wall paintings from an Assyrian royal residence at Til Barsip (modern Tell ‘Ahmar), Syria and allowed comparisons to be made with contemporary textiles, jewellery and monumental architecture. The same methodology will be applied to other reliefs in the British Museum in order to extend the understanding of Assyrian and Achaemenid polychromy and to assess the potential effects that moulding and casting the reliefs in the nineteenth century may have had.

EXPERIMENTAL APPENDIX

VIL imaging

The individual components in the equipment used are as follows. For excitation, two identical fluorescent radiation sources (Philips TLD 58W/35) are placed symmetrically at approximately 45º to the focal axis of the camera. The luminescence emission from Egyptian blue is captured using a figure 4. Wall painting from an Assyrian royal residence at Til Barsip Canon 40D camera from which the IR-blocking filter has (modern Tell ‘Ahmar). The colour patterns are very similar to those found on the relief depicting a horse’s head. Image by Lucien Cavro been removed; the camera is operated in fully manual mode. [15] The sensitivity range is selected by placing a Schott RG830

61 GIOVANNI VERRI, PAUL COLLINS, JANET AMBERS, TRACEY SWEEK AND ST JOHN SIMPSON filter in front of the lens. A reference grey scale, comprising REFERENCES a set of Lambertian black, grey and white tiles, is placed in the same plane as the object under investigation. These 1. Brinkmann, V., ‘Research in the polychromy of ancient sculpture’, in Gods in color: painted sculpture of classical antiquity, Spectralon® references have uniform reflectance properties ed. V. Brinkmann and R. Wünsche, Stiftung Archäologie and across the ultraviolet, visible and infrared spectral ranges Staatliche Antikensammlungen und Glyptothek, Munich (2007) under investigation; crucially for this study, they show no 21–28. Studies luminescence properties. A visible (c.400–700 nm) image 2. Wallert, A., ‘Unusual pigments on a Greek marble basin’, in Conservation 40 (1995) 177–188. of the objects was also always made for comparison. All 3. Stodulski, L., Farrell, E. and Newman, R., ‘Identification of ancient images were acquired as ‘raw’ images and transformed into Persian pigments from Persepolis and Pasargadae’, Studies in 4256 × 2848 pixel resolution images in 16-bit TIF (tagged Conservation 29 (1984) 143–154. image file) format [10]. 4. Ambers, J.C. and Simpson, St J., ‘Some pigment identifications for objects from Persepolis’ (2005) www.achemenet.com/ressources/ enligne/arta/pdf/2005.002-Ambers-Simpson.pdf (accessed 25 March 2009). Raman spectroscopy 5. Botta, P.E. and Flandin, E., Monument de Ninive, Imprimerie Nationale, Paris (1849) Plates 107–114. 6. A Guide to the Exhibition Galleries of the British Museum, Raman spectroscopy was carried out using a Jobin Yvon Bloomsbury, Trustees of the British Museum, London (1884). LabRam Infinity spectrometer using green (532 nm) and 7. Loud, G., Khorsabad, Part I: excavations in the palace and at a city near IR (785 nm) lasers with maximum powers of 2.4 and gate, University of Chicago Press, Chicago (1936). An investigation of corrected UV-induced fluorescence 4 mW at the sample respectively, a liquid nitrogen cooled 8. Verri, G., for the investigation of polychromy, MA dissertation, Courtauld CCD detector and an Olympus microscope system. Samples Institute of Art (1997) (unpublished). of a few grains were collected using a clean scalpel, placed 9. Verri, G., ‘The use and distribution of Egyptian blue: a study by onto a microscope slide and measured without any further visible-induced luminescence imaging’, in The Nebamun wall paintings: conservation, scientific examination and display at the treatment. The resultant spectra were identified by compar- British Museum, ed. A. Middleton and K. Uprichard, Archetype ison with a British Museum in-house database. Publications, London (2008) 41–50. 10. Verri, G., ‘The spatial characterisation of Egyptian blue, Han blue and Han purple by photo-induced luminescence digital imaging’, Analytical and Bioanalytical Chemistry 394(4) (2009) 1011–1021 [DOI: 10.1007/s00216-009-2693-0]. ACKNOWLEDGEMENTS 11. Riederer, J., ‘Egyptian blue’, in Artists’ pigments: a handbook of their history and characteristics, Vol. 3, ed. E. FitzHugh, National One of the authors (GV) is a postdoctoral science fellow in the Depart- Gallery of Art, Washington DC (1997) 23–40. ment of Conservation and Scientific Research at the British Museum 12. Pozza, G., Ajo, D., Chiari, G., De Zuane, F. and Favaro, M., supported by a grant from The Andrew W. Mellon Foundation. ‘Photoluminescence of the inorganic pigments Egyptian blue, Han blue and Han purple’, Journal of Cultural Heritage 1 (2000) 393–398. 13. Accorsi, G., Verri, G., Bolognesi, M., Armaroli, N., Clementi, C., Miliani, C. and Romani, A., ‘The exceptional near-infrared AUTHORS luminescence properties of cuprorivaite (Egyptian blue)’, Chemical Communications (2009) 3392–3394 [DOI: 10.1039/b902563d]. Giovanni Verri ([email protected]) and Janet Ambers 14. Thureau-Dangin, F. and Dunand, M., Til-Barsip, Librairie Orien- ([email protected]) are scientists and Tracey taliste Paul Geuthner, Paris (1936). Sweek ([email protected]) a conservator, all in the 15. Parrot, A., Nineveh and Babylon, Thames and Hudson, London Department of Conservation and Scientific Research. Paul Collins (1961) Plate 347. ([email protected]) and St John Simpson (ssimpson@ 16. Albenda, P., Ornamental wall painting in the art of the Assyrian thebritishmuseum.ac.uk) are curators in the Department of the Middle Empire: Cuneiform Monographs 28, Styx-Brill, Leiden (2005). East at the British Museum. 17. Pittman, H., ‘Jewelry’, in Treasures from the royal tombs of Ur, ed. R.L. Zettler and L. Horne, University of Pennsylvania Museum, Philadelphia (1998) 87–122. 18. El-Wailly, F. and es-Soof, B.A., ‘The excavations at Tell es-Sawwan. First Preliminary Report (1964)’, Sumer 21 (1965) 17–32. 19. Reade, J.E., ‘Assyrian architectural decoration: techniques and subject-matter’, Baghdader Mitteilungen 10 (1979) 17–49.

62 A Great Lakes pouch: black-dyed skin with porcupine quillwork Pippa Cruickshank, Vincent Daniels and Jonathan King

Summary A late eighteenth-century North American pouch (1937,0617.1) represents an important type of a black-dyed skin bag decorated with porcupine quillwork. The pouch was made by women of the Ojibwa or Ottawa people and was probably used in medicine ceremonies. It came to the British Museum in the mid-twentieth century and when first examined in detail in the 1970s had already deteriorated. The skin has degraded due to the presence of a black dye, although an early watercolour painting of the bag discovered in the 1990s illustrates how the bag once looked. Black dyes containing both iron and tannin are well known to increase the rate of deterioration of many organic substances and the pouch was found to contain 1.63% iron. Experiments with a series of brain-tanned skin samples stained with various iron-tannin solutions and artificially aged showed that the presence of iron accelerated the deterioration of the skin. A conservation treatment carried out in the 1970s, which included consolidation with soluble nylon and backing with nylon net adhered with an early thermoplastic adhesive, was no longer succeeding in keeping the bag intact, and further conservation was carried out to protect the 75% of the bag that survives. As the pouch is of a rare type it was decided to infill the missing areas to make it more suitable for display. The use of adhesives was kept to a minimum and solvent-reactivated adhesives were chosen in preference to those reactivated by heat. No further chemical stabilization was attempted in this treatment.

INTRODUCTION while black, anaerobic, iron-rich muds occur naturally and have been much used for dyeing. It is likely that black In the Northeastern Woodlands of North America, buck- dyeing techniques were developed after it was observed skin for bags and clothing was sometimes dyed dark brown – in disparate communities – that tannin-rich vegetation or black to provide a strong colour contrast with the dyed became dyed black when accidentally immersed in certain porcupine quillwork or dyed moose hair with which it was muds. In addition, a black coloration can also be produced often decorated. The native use of flattened dyed porcupine by the reaction of iron corrosion products with tannins, for quillwork for appliqué is unique to North America. The example when iron nails that have been hammered into pouch from the Great Lakes (1937,0617.1: Figure 1) that oak, or through vegetable-tanned leather, corrode. is the subject of this contribution is made of black-dyed These black iron/tannin dyes are widely found in arte- semi-tanned skin decorated with native religious imagery facts, for example in inks such as iron gall ink on manu- in dyed porcupine quillwork and dates to the period 1755– scripts and in black dyes used on textiles made of silk, 1780. Although it is one of a small group that are known to wool, cotton or other plant fibres. In each case the black have survived, much of the front flap and parts of the main dye can accelerate the rate of deterioration of the object, bag have completely disintegrated. causing the material to become brittle and weak with little Black-dyed objects are common to most civilizations. tensile strength; this leads to easy tearing or shattering and, Although black or dark-coloured dyes can be made by in the case of skin, to the surface becoming very friable combining several dyes, for example blue and red, the and powdery. On skin this deterioration is sometimes majority of natural blacks are made from tannins (plant called ‘black rot’ a term analogous to ‘red rot’, a phenom- polyphenols) and a source of iron. The ingredients for enon in which undyed, tanned leather becomes weak and dyeing are commonly available: tannins are present in a wide powdery while becoming redder. The principal mechanism variety of plants, barks, leaves and fruits of trees or shrubs, of deterioration in both red and black rots is oxidation of which possess high contents of easily extractable tannins, the leather.

63 PIPPA CRUICKSHANK, VINCENT DANIELS AND JONATHAN KING

blue, green or brown stain in the presence of iron; for more details see [3; pp. 691–701]. Many natural sources of tannin contain a mixture of the two types. When extracted from these sources, the tannins are colourless or have a pale tint, only forming an intense dark colour when complexed with iron or another metal. The iron used in dyeing or staining derives either from a soluble iron source such as the sulphate or acetate salts (or an iron-containing mud or clay), or from a solid iron source such as iron dust from sharpening iron or steel tools, or corroded iron (rust). In some cases, as mentioned above, a proportion of the iron may derive from a metal vessel in which dyeing is conducted, particularly if this is corroded. There are different methods for the creation of these black dyes, either in dye baths or directly on the surface of an object. If a dye bath is used, the black dye can be formed in the dye vat before the object is exposed to the colorant or by adding the iron and tannin components sequentially. Many natural dyes need a two-stage process in which a metal-containing mordant is applied first, followed by an organic material, but in black dyeing of skin it is not so critical which of the dye components is applied first as both have a strong affinity for the proteinaceous substrate. For example, since tannins have the characteristic property of being able to tan – or colour – animal skins, vegetable- tanned skins can then be stained black by deliberate or accidental contact with iron. There are two principal mechanisms for the decay – oxidation and hydrolysis. It is known that iron is a catalyst for the oxidation of a number of substrates, for example in the ‘black rot’ described above. Although the iron in the dye figure 1. The pouch after completion of the recent conservation is probably inert while it is bound in the initial dye complex, treatment when this deteriorates free iron is released that is chemically active; free iron may also be present due to an excess of iron in the dyeing process. In addition, other metal ions, In North America, materials including skins and porcu- such as those of copper (which is often a contaminant in pine quills were dyed by soaking and boiling in water iron sulphate used in dyeing), can act as oxidation catalysts. mixed with plant substances and an iron-containing clay Hydrolysis of proteins reduces the length of the molecular [1]. In the Great Lakes area the bark of a walnut tree often chains in the collagen fibres by breaking some of the chem- provided the tannin for the brown-black dye used for the ical bonds that join the constituent amino acids together. skins [1]. If the dyeing was carried out in a copper or iron Excessive acidity (or indeed alkalinity) increases the rate of pot, metal ions leached from the vessel might have affected hydrolysis. The physical manifestation of both these degra- the colour, as these could also act as a mordant to help fix dation mechanisms is a reduction of tensile strength and the dye [2]. extensibility in the fibres.

FORMATION AND DECAY OF IRON/TANNIN PREVIOUS WORK ON BLACK-DYED SKINS BLACK DYES The few published conservation treatments on similar The tannins used to form black dyes are complex polyphe- black-dyed skin artefacts were consulted prior to devel- nols that can be classed either as hydrolyzable tannins oping the strategy for the recent treatment of the pouch. (those tannins that are susceptible to decomposition of an Investigations on black-dyed native North American ester bond in acidic solutions), which generally produce skin and wool material were carried out at the Canadian a black/blue coloration, or condensed tannins (polymeric Conservation Institute (CCI) in the 1980s [4]. Elemental tannins less susceptible to acid hydrolysis), which give a analysis of the skin of a badly degraded black moccasin

64 A GREAT LAKES POUCH: BLACK-DYED SKIN WITH PORCUPINE QUILLWORK included in this study was carried out using X-ray chosen to adhere an open-weave polyester lining, as it emission spectroscopy and showed the presence of sulphur fulfilled most of the desired criteria. In particular, Beva® and iron. The degree of degradation was assessed by meas- 371 was felt to be the most suitable adhesive to provide uring the leather shrinkage temperature (Ts) and by exam- the necessary strength and flexibility to enable the cape to ining the skin by polarizing light microscopy (PLM). be displayed as worn while maintaining the drape of the Under the microscope, the collagen fibres of which skin is garment [8]. Beva® 371 is now commonly used for skin composed can be seen to shrink suddenly at a particular repairs, as it provides a nap bond without the adhesive temperature during heating in water; the temperature at penetrating the skin [12]. which shrinkage occurs (Ts) is used as an indicator of degradation, as the Ts decreases as the skin degrades [5]. New skin and semi-tanned leather fibres shrink over the range Experiments with dyed leather samples 62–68°C in water. The fibres in the moccasin sample did not shrink, indicating a Ts below ambient temperature and, In 1998 several samples of traditionally dyed, brain-tanned hence, an advanced degree of degradation. Under crossed leathers were obtained from Brent Boyd (a craftsman, artist polars, the fibres of undegraded leather appear white due to and researcher from Williamsburg, Ontario who was trying birefringence, while the fibres from the moccasin showed to replicate traditional Native American techniques) and no birefringence as they had degraded and lost their crys- subjected to accelerated ageing; the methods of production talline structure [4, 5]. for these samples have already been described [13]. The Also in the 1980s, Fenn investigated adhesives and leather samples in this group were undyed skin and skin consolidants for skins, including very brittle black skins that had been surface-treated with solutions or suspensions affected by ‘black rot’. While advising that the use of containing: iron; hemlock (the bark of the Eastern hemlock consolidants should be restricted as much as possible, Tsuga canadensis); iron with hemlock; iron with hemlock Pliantex (an ethyl acrylate resin), dissolved in slow- and black walnut; iron with hemlock and sumac. evaporating solvents, was suggested as a possible consoli- Each sample was cut in two so that a replicate sample was dant for degraded skins [6]. Chapman suspected that the available. The surface pH of a portion of each of the treated stiff and friable condition of some black-dyed moccasins skins was measured using a surface pH electrode and then was due to a metal salt used in the dyeing process [7]. The artificially aged at 70°C for 28 days in a glass desiccator black dye had not penetrated the skin completely and the humidified to approximately 75% relative humidity using surface of the skin was acidic, with a pH of 4. Attempts to a glycerol/water mixture [14]. As the samples were only consolidate and improve the flexibility with sorbitol, glyc- surface dyed, the strength of the dyed skin was assessed erine and Bavon ASAK 520S were unsuccessful [7]. The use qualitatively by rubbing a cotton swab over the surface to of such humectants or water-based consolidants would not see whether any black material was removed. be recommended today as water can increase the rate of No sample showed significant loss of material or dye acid-catalyzed hydrolysis. transfer to the swab before ageing, but all the treated skins More recently, a velvet cape trimmed with black-dyed except that dyed with hemlock alone were markedly more fur/skin was studied and conserved at CCI [8]. This large affected by rubbing after ageing, with the pale background circular cape, measuring about two metres across, possibly showing through in the rubbed areas. The colour of some originated from Ireland and dates to the last quarter of the samples had become browner and the cotton swabs rubbed nineteenth or first quarter of the twentieth century. The off small particles from the degraded fibres that could be black fur/skin had little tensile strength, the pH was 3.8 ± seen under the microscope when the swabs were examined.

0.1 and the Ts of the fibres varied from room temperature Any change in pH in the aged samples was negligible (–0.1 to 60°C [9]. The black dye was not positively identified, to 0.2), except for skin treated with a combination of iron, but it was suggested that it might be a synthetic oxidation hemlock and sumac, which decreased in pH from 5.6 to dye [10], and that copper and iron identified on the fur 4.7. Although the changes in pH are small, the increased were likely to be from dye mordants used to fix the dye to vulnerability of the surface in these experiments suggests the material. that iron-containing black dyes increase the rate of deterio- One of the authors (PC) assisted in the conservation ration of brain-tanned skins. of the black-dyed fur/skin trim of this cape during an internship at CCI in 1996 [11]. Although the hair was still firmly attached to the skin, the skin itself had broken into numerous pieces. The hair was probably in better condition THE BRITISH MUSEUM GREAT LAKES POUCH than the skin because it is composed of keratin as opposed to collagen. Although the surface on the flesh side of the History and cultural context skin was powdering, it had been decided not to consolidate it due to concerns over the stiffening that could result. The British Museum pouch (1937,0617.1) was acquired in Despite some concerns about applying heat to the weak the 1930s as a donation from Harry Beasley of the private and degraded skin, a heat-reactivated adhesive had been Cranmore Museum [15]. Purchased at an unidentified

65 PIPPA CRUICKSHANK, VINCENT DANIELS AND JONATHAN KING auction sale in the rooms of Stevens, Covent Garden, it was is Ojibwa [17]. That these pouches are likely to be Ojibwa at the time of acquisition undocumented. Dale Idiens, of is confirmed by the contemporary portrait of Sir John the Royal Scottish Museum commented on the significance Caldwell, who served in the King’s Regiment in North of the pouch during a visit to the British Museum 40 years America from 1776 to 1780. Caldwell is depicted in an later, during the late 1970s and, as a result, the pouch was original oil portrait, still in the possession of Caldwell’s conserved for display. In the early 1990s Michael Graham- family, wearing the hybrid costume of a military Ojibwa Stewart located one of perhaps 50 albums of watercolour (including a pouch) during a council meeting at the drawings by Sarah Stone showing objects in the Leverian Shawnee village of Wakatomica (now Dresden, Ohio) on Museum in London in the 1780s [16]. One of the 40 water- 17 January 1780 [18]. colours depicts the pouch at near life size (Figure 2), and The Ojibwa missionary Reverend Peter Jones, also this identification assisted in making the case for the ulti- known as Kahkewaquonaby, ‘sacred feathers’ or ‘sacred mately successful purchase of the album by the British waving feathers’, was depicted in early images with two Museum. At the moment little can be said of the pouch’s similar pouches of this type, one with a Thunderbird. history between about 1786, when Stone sketched it, and When he was photographed in 1845 by Hill and Adamson 1937 when it came to the British Museum. the costume and pouches were by then archaic [19, 20]. The Stylistically the pouch falls into a group of black-dyed practical use of the pouches is uncertain, but they may have bags associated with the American Revolution or War of contained personal items, or materials for ritual use such as Independence (1775–1783), many of which are decorated tobacco; both Caldwell and Jones are carrying pipe-toma- with Thunderbirds and Underwater Panthers, that is to say hawks in their portraits. Elaborate costumes of this type were mythic creatures of the Upper and Lower Worlds. Three perhaps first created as part of the diplomatic efforts associ- similar examples from the collection of General Frederick ated with Sir William Johnson, of Johnson Hall, Johnstown Haldimand, governor of British territory from 1778 to 1784, in the Mohawk Valley, New York, who was Superintendent in the Musée d’Yverdon, Switzerland, are in good condi- of Indian Affairs for the Crown from 1755 to 1774. While tion and are well documented: another is in the Canadian these costumes may have been designed for diplomacy, it Museum of Civilization [17].No original ethnic attributions is likely that the symbolism incorporated in the individual are provided, but Feest is satisfied that the pouch in Canada elements, especially the quilled decoration of religious articles, would have been extremely ambiguous in meaning. The Thunderbirds probably had different meanings to the women who made the objects, to the Ojibwa men who are likely to have gifted the pouches to Europeans, and to the men who wore the costumes as a means of communicating across ethnic divisions, both European and Native North American. Originally living around the northern and western Great Lakes in what is now Ontario, the Ojibwa became prominent in northern Minnesota and Wisconsin after European contact in the seventeenth century. They are the pre-eminent Algonquian-speaking hunters and trappers around the western and northern Great Lakes, known by themselves today as Anishnaabe, and in the United States as Chippewa. Long involved in the Canadian fur trade, with the French as their main allies, the defeat of France in the French and Indian (or Seven Years) War of 1753–1763 would have brought about major changes in every aspect of Ojibwa life. The creation of black-dyed pouches, with a Thunderbird animikii( in Fond du Lac dialect) depicted, may have come out of a period of rapid change, affecting Ojibwa religion both in the Grand Medicine Lodge or Midewiwin and Ojibwa shamanism [21]. For the Ojibwa, Thunderbirds used lightning bolts to kill underwater spirits, were associated with the creation and the protection of birds and provided associational names adopted at puberty (the source of Peter Jones’ name, which perhaps lies behind his dressing with a Thunderbird pouch for photography) [22]. The Beasley pouch considered here figure 2. Watercolour painting (British Museum Am2006,Drg.53) of is unusual in that the two Thunderbirds are depicted the pouch by Sarah Stone c.1785 with lightning.

66 A GREAT LAKES POUCH: BLACK-DYED SKIN WITH PORCUPINE QUILLWORK

figure 3. The pouch (British Museum 1937,0617.1) prior to conserva- figure 4. The pouch prior to recent conservation treatment tion treatment in the 1970s

The 1970s conservation treatment of the pouch and red-dyed hair, hanging down at the lower edge of the pouch are missing; just two of the 19 illustrated are now The pouch was in an advanced state of deterioration by the present. 1970s when it was first conserved; this is evident from the The pouch was conserved in the 1970s so that it could conservation record and photographs taken at the time, be exhibited at the Museum of Mankind in 1982 in an exhi- Figure 3. The front flap had become detached and only its bition entitled Thunderbird and Lightning[20]. The friable outer skin rim remained. Some of the lengths of coiled white skin was consolidated with a 5% solution of soluble nylon, porcupine quillwork had survived where the skin beneath a chemical modification of nylon 66 that is soluble in hot had not, so they were left unattached. Parts of the main bag methanol or ethanol (usually with some added water) and were also missing, including the upper left corner of the which forms a gel on cooling. This was a standard treatment bag (as viewed), the top edge and much of the right side of at the time [23]. Nylon net coated with an early thermo- the reverse (as viewed). The carrying strap, made of wool plastic adhesive, Vinamul 6515, was used as the backing to decorated with glass beads, was only tenuously attached to support and infill missing areas and to form the seams at the bag at one side. the sides of the bag. Comparing the pouch with Sarah Stone’s illustration gives This conservation treatment was re-evaluated in 2006 as a good idea of the original appearance of the bag, although the repairs were no longer helping to keep the bag intact. it is evident that there has been some artistic licence in The adhesive was failing and the front flap had become recording the detail [16]. The watercolour in Figure 2 shows detached from the main part of the bag, Figure 4. There were some of the features that are now missing from the bag. quite a number of separate small skin fragments secured Most noticeably, the central portion of the front flap was to the net on the upper left corner of the bag (as viewed), once decorated with a strip of brightly coloured red, yellow Figure 5. Some of the white stitched quillwork and skin frag- and black zigzag quillwork in a geometric design. In addi- ments on the front flap had become detached from the nylon tion, the majority of the tassels, composed of metal cones net and the net had developed some very unsightly holes

67 PIPPA CRUICKSHANK, VINCENT DANIELS AND JONATHAN KING

Quantitative analysis of the amount of iron in the leather was performed colorimetrically by extracting the iron into solution using hot 10% hydrochloric acid and then measuring the strength of the red colour formed by adding ammo- nium thioglycolate [25]. The iron content was found to be 1.63%, which is similar to the 2.0% found by Dignard and Gordon in a piece of badly deteriorated black-dyed fur that also contained 0.6% copper [8].Microscopic examination of the leather showed that the weak fibres had shattered into small fragments. The sample exhibited no birefringence and the fibres did not shrink on warming, suggesting a lack of

crystallinity, a low Ts and a much deteriorated state. figure 5. The fragmentary state of the top left corner of the bag prior It appears that the quillwork is less affected by the black to the recent conservation treatment dyes than the skin. Assuming that the black quillwork of this bag was dyed in a similar manner to the skin, this might be due to differences in susceptibility of the keratin proteins in where it had been used to infill the missing central area of the quill compared to the collagen proteins in the skin. the front flap. The remains of the glossy adhesive could be seen in the mesh of the net and, because the adhesive had Recent conservation treatment of the pouch become slightly tacky, the exposed net had attracted much powder from the degraded skin. The skin appeared stiffer than in the photographs taken prior to the 1970s treatment, The front flap was treated first as it was only attached to the which may have been caused by cross-linking of the soluble remaining bag at one side, enabling it to be moved aside to nylon. Sease pointed out the shortcomings of soluble nylon facilitate the work. The old nylon net was very gradually and it has not been regarded as a useful conservation material removed by gentle hand pressure and the application of a for some time [24]. minimal amount of acetone with a fine sable paintbrush as necessary. The skin was so impregnated with consolidant that further consolidation was ruled out and it was Analysis and investigation of the black-dyed skin decided to keep the use of adhesives to a minimum. Water- reactivated adhesives were avoided as they might stain the A useful first step in examining the degradation mecha- skin and because iron-catalyzed deterioration is accelerated nism is the confirmation of the presence of iron in the by humidity [26].Solvent-reactivated adhesives were chosen degraded artefact. The pouch was analysed by X-ray in preference to heat-reactivated adhesives of the type used fluorescence analysis (XRF), which can detect elements with in the previous treatment of this pouch, and in the treatment an atomic number greater than about 13 (aluminium). Iron of the degraded black-dyed fur trimmed velvet cape at CCI was detected, although as no specific calibration had been that has already been discussed. It was considered preferable carried out it was not possible to determine the quantity of to avoid the use of heat on such degraded skin and the pres- iron present. The XRF spectrum (Figure 6) of an area of the sure of using a heated spatula might have caused damage to bag shows that in addition to iron the only other element the stiff and inflexible pouch. detected was a trace amount of copper. The weakest areas around the rim of the flap, composed of many separate pieces, were first strengthened and held in place with small patches of a fine mulberry paper coloured with acrylic paints diluted in distilled water. These were adhered to the reverse using a 20% solution of Klucel G in industrial methylated spirit (IMS), which was chosen as it dried very quickly and was therefore unlikely to stain the skin. To provide the necessary support for the flap it was decided to use an encasing method, in which the skin is encased between two layers of fabric. There is a greater range of nylon nets available today than in the 1970s, including some finer, softer and sheerer fabrics suitable to be used as overlays. Although a sheer polyester fabric was considered because of its long-term stability, it was judged to be visually unac- ceptable as an overlay. Nylon net was, therefore, selected and once dyed to a suitable colour was barely noticeable except figure 6. X-ray fluorescence spectrum of the skin of the black-dyed on close viewing. Nylon net was, however, ruled out for the pouch lining as using two layers of net directly on top of each other

68 A GREAT LAKES POUCH: BLACK-DYED SKIN WITH PORCUPINE QUILLWORK can lead to a disturbing moiré effect. In addition, it was felt that a material providing greater support would be desirable. Non-woven polyesters were first investigated, but discounted as it was decided that a woven fabric was required to hold the sewing stitches of the repair adequately. A fine-woven cotton fabric was finally chosen as it was easy to dye to an appropriate colour with Solophenyl® azo dyes. The nylon net and some monofilament silk thread were dyed dark brown with Lanaset® direct dyes. The flap of the pouch was sandwiched between the dyed cotton backing (Figure 7) and the dyed nylon net overlay, encasing the fragments by stitching around their edges and the remaining sections of the flap using the dyed silk thread. Slits were cut in the net at the position of the tassels so that the net could be folded back to the reverse of the cotton backing and secured to it with the silk thread. The main bag of the pouch was then treated, Figure 8. The old net was first removed from the bag in areas where it came away easily but was left in place where it was felt that, due to the friable nature of the skin, its removal would be damaging. The small loose pieces of skin on the front and back were carefully removed after recording their position for future replacement. The vulnerable edges of the brittle skin were strengthened with mulberry paper using the method described above. Large sections of the skin of the main bag had survived intact, which made the encasing technique used for the flap inappropriate, as it would have necessitated completely covering the entire front of the bag including the quillwork decoration with an overlay of net. Dyed cotton fabric was again used as the lining fabric but, as it was not possible to stitch through the skin, it was here secured to the paper- figure 7. The flap of the pouch laid on top of the dyed cotton lining strengthened edges around the missing areas with a minimal fabric amount of adhesive. Various adhesive films were made by brushing adhesive onto polythene sheeting and letting it dry. By removing the polythene backing, a free film of adhesive was obtained. Paraloid® F10 was chosen as the most suitable of the adhesives tested as it adhered well to both the cotton fabric and the paper-backed skin. This adhesive was reactivated by introducing white spirits through a Gore-Tex® membrane. Working on one side of the bag at a time, the adhesive film was cut into small squares that were placed between the cotton lining and the paper-backed skin at intervals around the missing areas at points where, away from the extreme edges, the skin was stronger. White spirits were applied to a small piece of blotting paper and the adhesive reactivated figure 8. The skin remaining on the reverse of the pouch: the flap to locally through the membrane for five minutes while applying one side has been encased as described in the text slight finger pressure, which was maintained as it dried. For the overlay an adhesive was chosen that was soluble in a solvent that would not affect the Paraloid® F10 adhe- of the dyed nylon net used in the repair of the front flap sive used to secure the lining. Lascaux 498 HV adhesive was was coated with a 10% v/v solution of 498 HV adhesive in selected as it has been used successfully as a solvent reacti- distilled water using a wide brush and allowed to dry against vated adhesive on both textile and skin artefacts [27]. It is polythene sheeting. Two pieces of adhesive net were cut to often mixed with Lascaux 360 HV, but in this case 498 HV shape to fit the missing areas of the front and back of the bag, was used alone as 360 HV can remain slightly tacky and its leaving an area of overlap on the outer surface of the bag to greater flexibility was not essential for this treatment. Some protect the friable edges.

69 PIPPA CRUICKSHANK, VINCENT DANIELS AND JONATHAN KING

figure 9. Detail of the pouch with the flap open showing the new cotton lining fabric

figure 10. Detail of front of the pouch with the flap closed

The adhesive-coated net was carefully positioned on the the cotton fabric lining and the edges of the outer skin of outer surfaces of the bag, and gradually secured by local the bag. The outer edging of the bag at the top left corner reactivation through a Gore-Tex® membrane using blotters (as viewed) was additionally secured to the net by over- cut to shape and moistened with IMS. After applying the stitching with the dyed silk thread. Should it prove neces- blotters for three minutes the net was covered with poly- sary to remove the nylon net in future the Lascaux 498 HV thene to slow down evaporation and gentle finger pressure adhesive can be dissolved in acetone. was applied until the area was dry. The loose pieces of skin The dyed cotton fabric and adhesive net overlay were from the upper edge of the bag were repositioned during trimmed to the shape of the edges of the bag, but allowing this process. The adhesive net overlay was secured to both extra fabric to turn under along the edges. Finally, the

70 A GREAT LAKES POUCH: BLACK-DYED SKIN WITH PORCUPINE QUILLWORK seams of the bag were rejoined by stitching with the dyed reduce the concentration of free iron in the substrate. silk thread and the flap was joined to the main body of Neevel has suggested the use of phytates [31], but these the bag by stitching through the cotton fabric that replaced have so far only been tested and used in aqueous solutions, the missing skin at the upper edge of the bag, Figures 1, which limits their applicability in situations where mois- 9 and 10. ture is also known to be an agent of deterioration. A potentially useful range of stabilization treatments based on immidazolium antioxidants has been proposed by Kolar et al. [32], although these and the majority of other STABILIZATION OF BLACK-DYED SKINS treatments have been developed to address the degradation of paper by iron gall inks. To assess existing or new treat- Preventive conservation ments and develop solutions for the deterioration caused by iron/tannin colorants on other organic substrates, such All artefacts that have been treated with iron/tannin type as the skin in the pouch considered here, a three-year black dyes degrade faster than those that are undyed and collaborative research project has been initiated by the are a cause of concern for conservators. Iron gall ink draw- British Museum and the University of Manchester. ings and manuscripts have received much attention over the last decade and the vast majority of research on iron/ tannin blacks has been directed toward ink on paper or parchment [28]. CONCLUSIONS Although it can be confidently predicted that the rate of deterioration of any object can be decreased by lowering Conservation of the pouch has ensured that all the the storage temperature, the effect of lowering relative remaining sections are held together and that further humidity (RH) is more contentious. Those deterioration fragments will not be lost. Although display should be reactions that involve the presence of water will be slowed restricted to minimize any further degradation, informa- down by decreasing the RH, but there can be unwanted tion about the pouch will be available in the Collection side effects; for example, leather becomes more brittle Database on the British Museum website.1 In addition, the when RH decreases as the water it contains acts as a plasti- early watercolour gives an idea of its original appearance. cizer. While less humid conditions will probably decrease Scientific analysis carried out on the skin has added to the the rate of acid-catalyzed hydrolysis, the effect of RH on knowledge of how such iron/tannin dyes affect skin, and oxidation processes can be unpredictable. will contribute to research into non-aqueous methods of The use of antioxidants has not been shown to be effec- chemical stabilization for cellulose and protein artefacts tive, but an alternative strategy is to store the object in an affected by such black dye degradation that is now under oxygen-free environment. Several practical solutions have way. been developed in recent years. Most involve the use of bags made from oxygen-impermeable film into which objects are placed, along with sachets of an oxygen-absorbing compound, before sealing; in most cases an oxygen- ACKNOWLEDGEMENTS indicator ‘tablet’ is also included to show that the level of oxygen is minimal [29, 30]. One of the authors (PC) would like to thank the conservators and scientists at CCI, especially Carole Dignard, for initiating her interest in black dye degradation and the Winston Churchill Memorial Trust for making her internship at CCI in 1996 possible. Within the British Chemical stabilization Museum, the authors would like to thank Ian Taylor for help with the preparation and care of the pouch. Chemical stabilization processes can lower the concentration of the agents responsible for deterioration. Deacidi- fication is possible, and widely used in book and paper treatments, but it is not often used on proteins because its MATERIALS AND SUPPLIERS usefulness has not yet been proven. It also has the side effect that an increase in pH can be associated with a change of • Beva® 371, Klucel G, Lascaux 498 HV, Paraloid® F10 and Pliantex: Conservation Resources (UK), Ltd., Unit 2, Ashville colour, as black dyes often become brown in slightly alka- Way, Off Watlington Road, Cowley, Oxford OX4 6TU, UK; line conditions. Although it is generally considered that www.conservationresources.com. iron that is tightly bound in a dye complex is unable to • Gore-Tex®: Talas, 330 Morgan Avenue, Brooklyn, NY 11211, participate in degradation processes, the degradation of the USA; www.talasonline.com. • Lanaset® and Solophenyl® dyes: Huntsman Textile Effects, iron/tannin complex can, as mentioned above, release free Unit B, Adlington Court, London Road, Adlington, Cheshire iron(II) ions that are particularly aggressive in promoting SK10 4NL, UK; www.huntsman.com. further degradation leading to an autocatalytic reaction. A promising approach is, therefore, the use of agents that

71 PIPPA CRUICKSHANK, VINCENT DANIELS AND JONATHAN KING

AUTHORS 17. Feest, C.F., ‘Early Woodlands material at the Musée d’Yverdon’, in Three centuries of Woodlands Indian art: ERNAS Monographs ,3 Pippa Cruickshank ([email protected]) is a ed. J.C.H. King and C.F. Feest, ZKF Publishers, Altenstadt (2007) conservator and Vincent Daniels ([email protected]) 16–31. Three centuries of Woodlands an emeritus researcher, both in the Department of Conservation and 18. Jones, S., ‘Caldwell and DePeyster’, in Indian art: ERNAS Monographs 3 Scientific Research. Jonathan C.H. King (jking@thebritishmuseum. , ed. J.C.H. King and C.F. Feest, ac.uk) is Keeper of the Department of Africa, Oceania and the Amer- ZKF Publishers, Altenstadt (2007) 32–43. Sacred feathers: the Reverend Peter Jones (Kahke- icas at the British Museum. 19. Smith, D.B., waquonaby) and the Mississauga Indians, University of Toronto Press, Toronto (1987). 20. King, J.C.H., Thunderbird and Lightning, British Museum Publica- tions, London (1982) 64–65. REFERENCES 21. Ritzenthaler, R.E., ‘Southwestern Chippewa’, in ‘Northeast’, ed. B. Trigger, in Handbook of North American Indians, Vol. 15, “Bo’jou, Neejee!”: profiles on Canadian Indian Art ed. W.C. Sturtevant, Smithsonian Institution, Washington DC 1. Brasser, T.J., , (1978) 743–759. National Museum of Man, Canadian Government Publication 22. Vecsey, C., Traditional Ojibwa religion, American Philosophical Centre, Ottawa (1976) 18. Quillwork of the Plains Society, Philadelphia (1983) 74. 2. Bebbington, J.M., , Glenbow-Alberta Insti- 23. Plenderleith, H.J. and Werner, A.E.A., The conservation of antiqui- tute, Calgary (1982) 13, 50. ties and works of art: treatment, repair and restoration Natural dyes: sources, tradition, technology and science , 2nd edn, 3. Cardon, D., , Oxford University Press, London (1971) 375. Archetype, London (2007). Analysis of fibres from “black tanned” skin artefact 24. Sease, C., ‘The case against using soluble nylon in conservation 4. Young, G., , work’, Studies in Conservation 26 (1981) 102–110. Analytical Report 2294, Canadian Conservation Institute (1984) 25. Vogel, A.I., A textbook of quantitative inorganic analysis, 2nd edn, (unpublished). Longmans, London (1951) 646. 5. Young, G.S., ‘Microscopical hydrothermal stability measurements 26. Barker, K., ‘Iron gall and the textile conservator’, in Strengthening of skin and semi-tanned leather’, ICOM Committee for Conserva- the bond: Science & Textiles, North American Textile Conserva- tion, 9th Triennial Meeting, Dresden , ed. K. Grimstad, ICOM, Paris tion Conference, Philadelphia Museum of Art, Philadelphia (2002) (1990) 626–634. 11. 6. Fenn, J., ‘Some practical aspects in the choice of synthetic resins for 27. Sturge, T., The conservation of leather artefacts: case studies from the repair of ethnographic skin and gut’, in Adhesives and consolid- the Leather Conservation Centre ants , Leather Conservation Centre, , ed. N.S. Bromelle, E.M. Pye, P. Smith and G. Thomson, Inter- Northampton (2000) 26–27. national Institute for Conservation, London (1984) 138–140. 28. Kolar, J. and Strilič, M., Iron gall ink: on manufacture characterisa- 7. Chapman, V., ‘The conservation of a group of North American tion and stabilisation, University of Lublijana, Slovenia (2006). moccasins: a textile conservator’s approach’, in Recent advances in Conservation of plastics: materials science, degrada- the conservation and analysis of artifacts 29. Shashoua, Y., , ed. J. Black, University tion and preservation, Elsevier Butterworth-Heinemann, Oxford of London, London (1987) 207–210. (2008) 198–201. 8. Dignard, C. and Gordon, G., ‘Metal ion catalysed oxidation of Journal 30. Shashoua, Y., ‘Ageless® oxygen absorber: from theory to practice’, skin: treatment of the fur trim and collar on a velvet cape’, in ICOM Committee for Conservation, 12th Triennial Meeting, of the Canadian Association for Conservation 24 (1999) 11–22. Lyon Deterioration of a black velvet cape , ed. J. Bridgland and J. Brown, James and James, London 9. Young, G., , Analytical Report (1999) 881–887. 3475, Canadian Conservation Institute (1996) (unpublished). Analysis of the dyes on a fur-trimmed cape 31. Neevel, J.G., ‘A potential conservation treatment for the treatment 10. Moffat, E., , Analyt- of ink corrosion caused by iron gall inks’, Restaurator 16 (1995) ical Report 3427, Canadian Conservation Institute (1996) 143–160. (unpublished). 32. Kolar, J., Možir, A., Strilič, M., Ceres, G., Conte, V., Mirruzzo, 11. Cruickshank, P., ‘Conservation in Canada: a Winston Churchill Conservation News V., Steemers, T. and de Bruin, G., ‘New antioxidants for treatment Travelling Fellowship’, 61 (1996) 26–28. of transition metal containing inks’, in Durability of paper and 12. Kronthal, L., Levinson, J., Dignard, C., Chao, E. and Down, J., writing 2, ed. M. Strilič and J. Kolar, Ljubliana Faculty of Chem- ‘Beva 371 and its use as an adhesive for skin and leather repairs: istry and Chemical Technology (2008) 20–21. background and a review of treatments’, Journal of the American Institute for Conservation 42 (2003) 341–362. 13. Daniels, V., ‘Degradation of artefacts caused by iron-containing dyes’, in Dyes in History and Archaeology 16/17 (2001) 212–215. Glycerol 14. Milner, C.S. and Dalton, N.N., , ACS Monograph No. 117, NOTE Reinhold, New York (1953). 15. Waterfield, A.H. and King, J.C.H., Provenance: twelve collectors of ethnographic art in England, 1760–1990, Somogy Art Publishers, 1. www.britishmuseum.org/research/search_the_collection_ Geneva (2006) 78–91. database.aspx (accessed 17 June 2009). 16. King, J.C.H., ‘Woodlands art as depicted by Sarah Stone in the collection of Sir Ashton Lever’, American Indian Art Magazine 18(2) (1993) 32–55.

72 Bronzes from the Sacred Animal Necropolis at Saqqara, Egypt: a study of the metals and corrosion Quanyu Wang, He Huang and Fleur Shearman

Summary More than 1800 bronze objects dating to c.600 bc were excavated from the site of the Sacred Animal Necropolis at Saqqara, Egypt between 1969 and 1971. While the important pieces had been accessioned by the Department of Ancient Egypt and Sudan and had been routinely cleaned using alkaline and/or acidic reagents in the 1970s, the residual group considered here, which includes numerous figurines and parts of sculpture, situlae and jewellery, had remained unregistered and uncleaned and so retained a burial corrosion crust. Both the metal substrates and the surface corrosion were studied to obtain information about objects that were under consideration for accession and to contribute to the wider study of this important site. Microscopy, scanning electron microscopy with energy dispersive X-ray spectrometry, X-ray diffraction and Raman spectroscopy were used for the microstructural and compositional analysis of metals and for the identification of the corrosion products on the surface. Of the five objects selected for metallographic study, two are tin bronzes and the others are leaded tin bronzes; four have as-cast structure while one (a ring) was cast and had been subjected to working and annealing. The pale blue corrosion on the surface was identified as a mixture

of chalconatronite (Na2Cu(CO3)2 3H2O) and copper sulphates, with smaller quantities of acetates, including sodium acetate trihydrate and sodium copper carbonate acetate. Chalconatronite and copper sulphates are likely to be part of the original burial concretion, while the acetates have probably resulted from the alteration of the original corrosion and the formation of new corrosion in the presence of acetic acid during storage, as these objects have been stored in wooden trays since excavation. In the case of a composite bird figure, the wooden body of the object may have been the cause of localized formation of the acetates on the bronze foot. In parallel to the scientific investigation, corrosion removal was carried out to reveal hidden decoration. Some of these objects have been cleaned and the unsuitable storage media have been replaced.

INTRODUCTION time of acquisition and some have been displayed in the public galleries. The residual group studied here had been The ruins of Memphis, known as the first city of pharaonic considered in poor condition and remained unregistered Egypt, are on the west bank of the Nile, around 30 km while stored in the reserve collections of the Department south of Cairo. To the west of the city is Saqqara, the great of Ancient Egypt and Sudan. The items in this group are all necropolis of Memphis, and on the west side of the bluff of made from copper alloys and include 26 single objects and North Saqqara lies the site of the Sacred Animal Necropolis three groups of miscellaneous fragments; among the objects (SAN). From 1964 to 1976, excavations were conducted by are numerous figurines and parts of sculptures, situlae and the Egypt Exploration Society (EES) at SAN and more than jewellery; most of the small bronzes discussed here can be 1800 bronze objects were found. The finds included statu- dated to approximately 600 bc. ettes and other ritual equipment, including altars, stands, Apart from a few objects that had been cleaned on site in censers, tongs, razors, ladles, skillets, strainers, ewers, jars, Egypt, using methods for which no details are available, the basins, dishes and situlae [1]. group retained their burial corrosion concretion. It would In the 1970s, some of the bronze finds from SAN were appear that they had been kept in a wooden cupboard on a donated to the British Museum by the EES and the majority wooden tray padded with cotton wool since the time of their of them were formally accessioned into the Museum collec- acquisition. Thick burial concretions including pale blue tions. Many of these bronzes were routinely cleaned at the corrosion products, which were said to have been present

73 QUANYU WANG, HE HUANG AND FLEUR SHEARMAN

(a)

(b)

(c)

(d)

figure 1. Four objects from which samples were taken for metallographic study in cross- section: (a) torso of Osiris, No. 8; (b) ring, No. 11; (c) Osiris, No. 12; and (d) Osiris, No. 14. Scale bars show 1 cm divisions

at the time of excavation, were observed on some objects SAMPLING AND EXPERIMENTAL [2]. However, the formation of new pale blue corrosion efflorescences, identified as copper compounds containing The pale blue corrosion products were taken for analysis acetate (ethanoate) and/or formate (methanoate) has often from five objects and an unidentified ‘lump’ of corrosion. been associated with the side effects of certain display or The corrosion products were selected with the aim of iden- storage environments [3–6]. Previous chemical treatments tifying the causes of the corrosion, which in this instance have also been reported as responsible for the formation of derive either from burial or from the conditions in which these types of corrosion products on copper alloys [7–10]. the objects were stored (or a combination of both). The Here, the identification of corrosion products was carried corrosion products were identified using X-ray diffraction out for the group of unaccessioned objects and the causes (XRD) combined with elemental analysis using a scan- of corrosion are discussed. ning electron microscope (SEM) equipped with an energy Metallographic samples were taken from a small number dispersive X-ray analyser (EDX). Raman spectroscopy was of the objects to enable studies of metalworking technology also used to detect any organic salts present, as XRD is not to be made and to assist in an understanding of the devel- very sensitive to copper formate or acetate. Cross-sections opment of corrosion on the surfaces. It was hoped that this were taken from four objects (Figure 1) and two fragments technical investigation would also contribute to the wider to allow metallographic study of the metals using micros- study of the important site of Saqqara. copy and SEM-EDX. These objects were selected in order to

74 BRONZES FROM THE SACRED ANIMAL NECROPOLIS AT SAQQARA, EGYPT obtain maximum technical information while minimizing damage; the sample preparation and analytical techniques are described in the experimental appendix.

COMPOSITION AND MICROSTRUCTURE OF THE METALS

The condition of the objects varied, with some being partially corroded and others having corroded throughout their depth, leaving little metal remaining, Table 1. It was found by EDX analysis that five objects were tin bronzes of which three were leaded tin bronzes. The tin content was found to be in the range 1.6–7.0 wt%, with a lead content in the range 8.4–32.0 wt%. The lump of corrosion (No. 29) was figure 2. Photomicrograph of a lump of corrosion (No. 29), suggesting probably originally part of a wire or ring (Figure 2); EDX that the original object was a wire or ring. Image width: 3.45 mm analysis suggested it was a leaded tin bronze.

figure 3. Photomicrograph of a polished section of the ring (No. 11) figure 4. Photomicrograph of a polished section of an Osiris figure showing an annealed structure; etched with ethanolic iron(III) chlo- (No. 14) showing a dendritic structure; etched with ethanolic iron(III) ride. Image width: 0.27 mm chloride. Image width: 0.68 mm

table 1. The composition and microstructure of the bronze objects studied Sample Object Metal Cu Sn Pb As Other Microstructure Comments No. thickness wt% wt% wt% wt% elements (mm) wt% 8 Osiris torso 4.1 80.2 3.1 15.9 0.8 As-cast equiaxed with Corrosion penetration is 1.1 mm. eutectoids on grain Pitting corrosion and large voids due boundaries to loss of Pb globules were observed 11 Wire or earring 1.3 91.6 7.0 – 0.8 0.6 S Recrystallized structure with Metal remained in most areas, but annealing twins corrosion penetrated through in some areas 12 Osiris 2.4 88.4 1.6 8.4 – 1.6 Cl As-cast equiaxed without Corrosion has penetrated through eutectoids the metal with a small area of metal remaining 14 Osiris 3.0 64.4 2.1 32.0 0.8 0.2 Cl Dendritic structure Corrosion penetration is 0.8 mm with large voids due to loss of Pb globules 18 Fragment 1.4 94.6 3.1 – – 1.5 Si As-cast equiaxed without Corrosion has penetrated through 0.6 Cl eutectoids the metal with islands of metal 0.2 Fe remaining 29 Fragment 3.0 * * * Pseudomorphic dendritic Probably a wire that has completely structure corroded Note: * indicates detected but not quantiﬁed

75 QUANYU WANG, HE HUANG AND FLEUR SHEARMAN

All the samples examined except for the ring (No. 11) CORROSION PRODUCTS ON THE COPPER showed an as-cast structure; the ring has a recrystallized ALLOYS equiaxed structure with annealing twins, Figure 3. All the samples with an as-cast structure had less than 5% tin, Background which is normally the level at which the (_+b) eutectoid phase begins to appear, but this depends on the cooling Blue corrosion products on copper alloy artefacts have rates of the alloy [11]. It is notable that eutectoids were been studied by conservators and scientists for more present in some samples (e.g. No. 8 and No. 14), but not in than 50 years. Chalconatronite (sodium copper carbonate others that had similar levels of tin. Although samples No. hydrate: Na2Cu(CO3)2 3H2O), which is greenish blue to 8 and No. 18 both had equiaxed structures and contained pale blue, has often been found on archaeological copper the same amount of tin, eutectoids were found in No. 8 but alloys. It was first discovered on ancient Egyptian objects not in No. 18. Prior to etching for metallographic exami- in 1955 by Gettens and Frondel [16]. It can be a natural nation, sample No. 14 appeared to have a granular struc- corrosion product on Egyptian bronzes due to the abun- ture but, although it contains only 2.1% tin, after etching it dance of alkali carbonates in the soil in Egypt [17]. It can showed a dendritic structure with eutectoids in the inter- also be a result of conservation treatments that include dendritic regions, Figure 4. This suggests that these objects sodium sesquicarbonate (trisodium hydrogendicarbonate: cooled at different rates after casting; those with eutectoids Na2CO3 NaHCO3), which was used in the past as a standard or dendrites must have been cooled quickly [12]. The ring stabilization process for archaeological copper objects [7– or earring had a recrystallized granular structure with 9]. Some chemical cleaning agents used on copper alloy annealing twins, indicating a cycle of casting, working artefacts, including Calgon (a proprietary water softener), and annealing. The last two processes in the cycle could zinc and sodium hydroxide, alkaline solutions of Rochelle have been repeated several times and the final step was salt (potassium sodium tartrate) and alkaline glycerol, are annealing, which is evident from the presence of annealing also the sources of sodium for the formation of chalco- twins in the grains, Figure 3. natronite [10]. Apart from the sodium copper carbonates, Lead is immiscible in copper and is present as globules other pale blue corrosion products, for example sampleite in the alloy, Figure 5. These lead globules are sometimes (NaCaCu5(PO4)4Cl 5H2O), have also been found on objects corroded and replaced by lead carbonate (cerussite) and from Memphis [18]. copper(I) oxide (cuprite) [13], which is the case here, see In recent years, unusual pale blue corrosion prod- Figure 5. The addition of lead does not affect the structure ucts, including copper acetate, copper formate, sodium of the bronze but it makes the bronze easier to cast because copper carbonate acetate and sodium copper formate it improves the fluidity of the metal in the melt. Of note is acetate, have been reported on copper alloy artefacts in that lead was found in these three cast Osiris figures but not museum collections [3–6]. These corrosion products are in the earring or the fragment that was analysed. As would often associated with the presence of acetic and formic be expected at this late period, the Egyptian craftsmen were acids emitted from materials within the display or storage clearly aware that lead made the casting easier [14, 15]. environment and it appears that the phenomenon of pale blue corrosion is far from rare in museum collections [19]. Trentelman et al. discovered a new pale blue corrosion product of copper containing sodium, formate and acetate ions on Egyptian, Greek, Assyrian and Chinese artefacts [6]. This corrosion product was also found on a silver kantharos in the British Museum collection (GR 1962,1212.1) that contains very little copper [20]. In this instance the new corrosion was clearly associated with incomplete removal of a reagent containing formic acid that reacted with the sodium-containing mild abrasive used to clean the object in a later treatment. Since all the pale blue corrosion products analysed here were from untreated objects, the effect of past conservation treatments on the formation of this type of corrosion product can be eliminated and they must have formed either in burial or during storage.

Identification of the corrosion products figure 5. Backscattered electron image of a sample from the torso of Samples of the pale blue corrosion products were taken Osiris (No. 8) showing the presence of a copper eutectoid (α+b) and lead globules (which appear light); some of the globules have partly for XRD analysis from four objects, including an arrow- corroded head (No. 2), a foot (possibly of an ibis: No. 5, Figure 6),

76 BRONZES FROM THE SACRED ANIMAL NECROPOLIS AT SAQQARA, EGYPT table 2. XRD results for the corrosion products from the Saqqara bronzes compared to chalconatronite and published data for the pale blue corrosion termed ‘sodium copper carbonate acetate’ [4]: d = d-spacing; I = relative intensity

Chalconatronite ‘Pale blue’ Sample from Sample from Sample from Sample from Sample from ICDD 22-1458 [4] No. 2 No. 5 No. 6 No. 8 No. 29 d (Å) I (%) d (Å) I (%) d (Å) I (%) d (Å) I (%) d (Å) I (%) d (Å) I (%) d (Å) I (%) 10.50 100 10.71 100 10.71 100 10.71 100 11.62 75 10.00 40 10.04 25 10.04 25 9.98 25 9.00 20 9.63 20 8.06 30 8.00 70 7.96 50 7.96 45 7.96 35 8.04 10 7.82 50 7.69 20 7.69 55 7.72 30 7.76 80 7.76 100 7.20 60 7.13 30 7.13 25 7.11 30 6.90 100 6.91 65 6.91 90 6.88 75 6.92 100 6.70 30 6.70 45 6.68 100 6.71 30 6.70 90 6.50 50 6.41 20 6.41 25 6.41 20 5.80 10 5.82 25 5.59 40 5.50 20 5.34 20 5.43 15 5.43 20 5.64 30 5.40 20 5.18 70 5.24 20 5.21 25 5.21 25 5.25 15 5.00 10 5.18 15 5.15 20 5.15 25 5.17 15 4.85 30 4.81 30 4.70 10 4.64 20 4.64 25 4.64 30 4.58 25 4.57 40 4.55 15 4.55 20 4.55 20 4.55 25 4.72 25 4.30 30 4.33 15 4.31 20 4.31 30 4.33 25 4.21 40 4.21 20 4.19 20 4.18 80 4.17 25 4.16 30 4.19 25 4.17 30 4.10 50 4.09 20 4.09 25 4.13 30 4.10 10 4.09 15 4.05 20 4.00 20 4.07 25 4.02 20 3.91 30 3.93 20 3.93 50 3.91 30 3.95 10 3.85 65 3.80 30 3.77 20 3.68 90 3.72 10 3.66 20 3.65 30 3.64 30 3.67 30 3.63 40 3.65 10 3.60 40 3.45 40 3.52 30 3.48 25 3.55 30 3.52 25 3.44 20 3.48 20 3.41 30 3.44 20 3.42 25 3.41 25 3.37 40 3.36 20 3.34 25 3.29 10 3.31 10 3.31 20 3.31 55 3.17 20 3.23 10 3.20 20 3.17 30 3.17 40 3.20 60 3.12 40 3.10 30 3.08 35 3.04 10 3.03 30 3.06 30 3.00 50 2.99 80 2.99 55 3.00 10 2.98 40 2.98 45 2.98 45 2.97 45 2.91 50 2.92 10 2.89 60 2.87 15 2.87 20 2.87 25 2.88 10 2.88 30 2.852 70 2.847 50 2.84 10 2.84 15 2.86 20 2.86 20 2.86 10 2.780 30 2.75 10 2.76 15 2.73 20 2.74 30 2.78 10 2.690 30 2.71 25 2.673 50 2.67 10 2.67 10 2.630 20 2.65 20 2.64 25 2.63 25 2.66 30 2.612 40 2.62 15 2.62 25 2.605 40 2.60 30 2.590 20 2.530 60 2.55 10 2.56 35 2.510 60 2.51 10 2.460 40 2.47 20 2.450 20 2.44 10 2.45 25 2.44 25 2.43 20 2.45 10 a broken situla (No. 6), an Osiris torso (No. 8) and a frag- in sandy soils, and sodium copper carbonate acetate, a pale ment (probably a lump of corrosion: No. 29), see Table blue corrosion product found on copper alloy artefacts in 2. The diffraction data for chalconatronite, a common museum collections in recent years, are also listed in Table natural corrosion product often found on bronzes buried 2 for comparison.

77 QUANYU WANG, HE HUANG AND FLEUR SHEARMAN table 3. Analytical results for the pale blue corrosion products

Sample No. Object Elements identified by Corrosion products identified by XRD Corrosion products identified by EDX Raman spectroscopy 2 Arrowhead Cu, Na and O Chalconatronite, copper sulphate hydrates, Not analysed sodium acetate trihydrate and sodium copper carbonate acetate (?) 5 Foot of Ibis (?) Chalconatronite, copper sulphate hydrates, Sodium copper carbonate acetate sodium acetate trihydrate and sodium copper carbonate acetate (?) 6 Broken situla Cu, Na, Ca, Si, O and S Chalconatronite, copper sulphate hydrates, Sodium acetate trihydrate and sodium (Pb, Cl and P in ‘spots’) quartz, sodium acetate trihydrate and sodium copper carbonate acetate copper carbonate acetate(?) 8 Torso of Osiris Chalconatronite Sodium acetate trihydrate 29 Lump of Cu, Na, O, Si, Al, Ca Zapatalite Not analysed corrosion and S

The diffraction patterns for these samples are very complex; those for sample Nos 2, 5 and 6 seem similar and contain mainly chalconatronite. A conclusive identification of such a complex mixture by XRD alone was difficult, so SEM- EDX was used to provide elemental analysis for the corrosion products to complement the XRD analysis. It was found that the corrosion products contained mainly copper, sodium and oxygen, with silicon, calcium, sulphur and chlorine present in some of the samples, Table 3. It is likely that most of the samples contain copper sulphate hydroxides, for example

Cu5(SO4)2(OH)6 5H2O, for which the main peaks listed in the International Centre for Diffraction Data (ICDD) data file (41-7) are 10.72, 5.37 and 3.59 Å. Quartz was also identified in some of the samples, including that from No. 6. Some of the d-spacings, particularly those for very small diffraction angles, gave a match with the pale blue corrosion products found in the British Museum collection by Thickett and Odlyha, which had been described as sodium copper carbonate acetate (‘pale blue’ in Table 2) [4]. This pale blue corrosion product had also previously been analysed by Raman spectroscopy and the data were therefore already figure 6. A bronze foot (No. 5), showing the pale blue corrosion on stored in the British Museum in-house Raman database. the upper part, which was inserted into a bird-shaped body that was As there are no ICDD data for sodium copper carbonate probably made of wood

figure 7. Raman spectrum of the pale blue corrosion from the foot figure 8. Raman spectrum of the pale blue corrosion from a broken shown in Figure 6. A reference spectrum of ‘sodium copper carbonate situla (No. 6). A reference spectrum of commercial grade sodium acetate’ from the British Museum in-house database is shown for acetate trihydrate is shown for comparison comparison

78 BRONZES FROM THE SACRED ANIMAL NECROPOLIS AT SAQQARA, EGYPT acetate, the pale blue corrosion products from these Saqqara the inside of object No. 6 (situla). The acetate ion in some bronzes were investigated using Raman spectroscopy; some of the corrosion products probably comes from one of two of their Raman spectra matched that for a ‘pale blue’ mate- sources, from the wooden trays and cupboards used to store rial described in the database as sodium copper carbonate many objects after excavation, or from wood in the burial acetate (Figure 7), while others gave a better match with environment – either wooden parts or bases in composite reference spectra for sodium acetate trihydrate, Figure 8. sculptures, or the wooden boxes that were sometimes used Those particles identified as sodium acetate trihydrate were for the burial of groups of statuettes. For example, the white in colour when seen under magnification, but when pale blue corrosion on the upper part of the bronze foot seen in bulk alongside other corrosion products appeared (Figure 6) could have derived from interaction of the metal pale blue. The XRD results (Table 2) showed the presence of with the wooden body of the original composite bird figure. sodium acetate trihydrate (ICDD 28-1030: d (Å) = 3.00, 7.73 Other sculptures show basal tangs, which may indicate that and 4.65) in some samples, including Nos 2, 5 and 6. Sodium they were originally associated with wooden bases that acetate trihydrate has been reported on Egyptian bronzes in could have been a factor in the formation of these corro- the British Museum collections [21], and on objects in other sion products. collections [3, 10]. However the identification of the ‘pale In cases where acetate-containing corrosion products blue’ as sodium copper carbonate acetate warrants further are present on objects that have not known association with study, as its characterization by Thickett and Odlyha was original material containing acetic acid, it seems more likely based on the examination of a physical mixture of malachite, that they have formed during storage. These acetates are copper acetate, sodium acetate and sodium carbonate, rather probably alteration products of chalconatronite resulting than a synthesized single phase compound [4]. from the absorption of acetic acid [5], but they could also Two samples of the corrosion products from No. 8 were be new corrosion products formed by direct interaction analysed, including a surface sample of pale blue material and between copper and the acetic acid emitted from wooden a sample of the greenish blue/pale blue materials beneath. The trays, etc. pale blue sample had been studied using XRD by Paterakis [22], and identified as sodium copper carbonate acetate by comparing the d-spacings with those published by Thickett and Odlyha [4]. Further examination of this pale blue sample CONSERVATION TREATMENTS by one of the authors (QW) using Raman spectroscopy has subsequently revealed that it contains mainly sodium acetate Parallel to the scientific investigation reported here, new trihydrate. As noted above, samples that appear pale blue work was carried out to investigate, and where necessary to the naked eye are often found to comprise a mixture of remove, burial concretions on a proportion of the bronzes. transparent white and blue particles when examined under The objects from Saqqara are the last major group of a microscope. Such mixtures of sodium copper carbonate recently excavated bronzes accessioned by the Department acetate and sodium acetate trihydrate were confirmed to of Ancient Egypt and Sudan, and many of these bronzes be present in some of the pale blue samples (e.g. No. 6) by had already been routinely cleaned in the 1970s [24]. As has Raman spectroscopy. The greenish blue/pale blue subsur- been noted, the residual group studied here was interesting face sample from No. 8 was identified by XRD as mainly for both metals scientists and conservators as, although they chalconatronite, Table 2. This confirms that corrosion is had been considered unpromising and remained unregis- frequently complex and localized, and that there is often tered, they retained their intact burial corrosion crust and more than one corrosion product present within thick only a few items had been cleaned on site. crusts that have formed over the long history of an object: Current approaches to conservation reflect the changes care needs to be taken in the interpretation of corrosion on since earlier, radical cleaning of collections of ancient museum artefacts. Egyptian bronzes, which was an almost routine process The diffraction patterns for the sample taken from No. 29 carried out at the British Museum and elsewhere; the were similar to that for zapatalite, Cu3Al4(PO4)3(OH)9 4H2O accession of a large volume of material from Saqqara led (ICDD 25-261), although the match is not perfect. Zapa- to a particularly intense period of cleaning activity at the talite is a pale blue mineral that has been identified as a Museum in the 1970s. The main purpose of all cleaning of corrosion product on outdoor bronze statues [23], although bronzes has been to remove the visually incoherent upper it has rarely been reported as a corrosion product on other corrosion layers to reveal hidden detail of original surfaces types of copper alloy objects. and unveil any decoration, Figure 9. Present methods are As discussed previously, the burial environment and more conservative and predicated on careful rationalization conservation treatments are two possible sources for the of any intervention that may remove material or change sodium present in chalconatronite, sodium acetate trihy- appearance. In terms of treatment choices, there are more drate and sodium copper carbonate acetate. The four options available to a metals conservator, particularly in the objects from Saqqara selected for analysis have not been stabilization of corrosion by the use of benzotriazole [25]. treated previously, so the sodium is likely to be from the soil. Passive approaches to stabilization may also be adopted by Sodium was detected by EDX in a soil sample taken from the control of the environment, with the aim of reducing

79 QUANYU WANG, HE HUANG AND FLEUR SHEARMAN

(a) (b)

figure 9. The torso of Osiris (No. 6) seen: (a) before conservation (the scale bar shows 1 cm divisions); and (b) in detail aftertreatment relative humidity in the vicinity of the bronze. Careful selec- under magnification. In some cases where corrosion was tion of materials used in the display and storage of bronzes particularly disfiguring, preliminary softening by soaking is also essential in order to screen out those that might in successive baths of distilled water was carried out. In promote the deterioration of the alloy. these cases residual loose, powdery and disfiguring deposits In this instance, it was necessary to conserve some of were removed by subsequent manual cleaning to either the the objects from this group as the loose corrosion on their level of the original surface of the bronze at the upper green surfaces meant that they could not easily be handled. An copper carbonate or the underlying red cuprite (copper(I) improvement in their storage conditions was also essential oxide) layers. to facilitate access to the collection. New storage throughout In terms of interventions, not all objects from this group the Museum is based on metal storage modules that are were treated in the same way; as mentioned above, corrosion gradually replacing those made of wood that may have was left in place where it was important to retain contextual caused damage to objects in the past. Inert packing mate- evidence such as corrosion or other burial-related stratig- rials such as polythene foam have also largely replaced raphy, unusual patterns of surviving corrosion or associ- cotton wool as a cushioning layer beneath and between ated mineral-preserved organic remains. A good example objects within the metal drawers. from this small group of untreated bronzes was an avian Treatment of these Saqqara bronzes varied in degree foot (No. 5), which was examined by X-radiography, but according to their surviving physical condition and any apart from the removal of sand accretions, was not cleaned intervention was balanced by an evaluation of the risk of of corrosion. An unusual corrosion pattern indicated it had loss of evidence contained in the residual corrosion. In formerly been part of a composite object and, in addition, every case preliminary examination using binocular micro- mineral-preserved woven linen textile remains were present scopy was followed by investigative cleaning to establish on areas of the object. The surviving corrosion on this object condition and the extent of any hidden detail. In addi- is unsightly and although the object would not be selected tion, X-radiography and technical recording preceded any for display on these criteria, evidentially it certainly has a corrosion removal and selective desalination. The range of value for the interpretation of an object now separated from treatments included the removal of compacted sand and its immediate context. Both the textile and upper corro- hard corrosion products using small hand-tools operated sion layers would have been permanently removed from

80 BRONZES FROM THE SACRED ANIMAL NECROPOLIS AT SAQQARA, EGYPT the surface of the object if strong reagents had been used to EXPERIMENTAL APPENDIX ‘clean up’ the object by improving its appearance and making the surface more visually coherent. Analysis of the unusual Microscopy corrosion pattern on the lower legs of the bird foot supports the suggestion that wood had formerly been present in this The stereomicroscope used for the investigation of surface localized area of the object and that this had induced corro- corrosion was a Leica Wild M8. A Zeiss AXIOVERT 100A sion in antiquity. Both falcon and ibis sculptures have been microscope was used for the metallographic study of the found among the bronze finds from Saqqara [1]; the form polished sections. of this foot indicates that it is more likely to have been part of an ibis than from the raptor family. Raman spectroscopy

Raman spectroscopy was carried out using a Jobin Yvon CONCLUSIONS Infinity spectrometer with a green (532 nm) laser, using a maximum power of 2.4 mW at the sample. The corro- The condition of the objects varied from light surface corrosion products were measured using a power of 0.6 mW to sion to more advanced corrosion with little residual metal avoid ‘burning’ the samples and to allow a comparison to be remaining. All the objects examined, except for the ring made with the reference spectrum in the British Museum (No. 11), showed an as-cast structure, while the ring has a in-house database for the ‘pale blue’ described as sodium recrystallized equiaxed structure with annealing twins. All copper carbonate acetate by Thickett and Odlyha [4]. of the metals were tin bronzes and the objects with thick walls were made of leaded tin bronzes. The differences in microstructure between the metals with similar tin contents XRD indicate different cooling rates during casting. The pale blue corrosion products on the surface of the X-ray diffraction was carried out with a Philips PW 1120/90 untreated objects were analysed and found to contain diffractometer using Cu _K radiation. The samples were mainly chalconatronite and copper sulphate hydroxides run at 40 kV, 15 mA for about an hour. Diffraction lines which were formed during burial. Organic copper salts, were identified by matching them with ICDD standards. including sodium acetate trihydrate and sodium copper carbonate acetate, which are often associated with the presence of acetic acid vapour in display and storage environ- Preparation of metallographic sections ments, were also identified in the corrosion layers studied here. The presence of sodium acetate trihydrate suggests The cross-sections were mounted in epoxy resin, ground that the existing burial corrosion is likely to have been and then polished using diamond paste to a finish of 1+ m. subject to further changes once in the Museum, although a After examination of the corrosion layers, the polished direct interaction between the metal and acetic acid emitted sections were etched using ethanolic iron(III) chloride to by wooden storage trays or cupboards cannot be ruled out. reveal the metallographic structure of the metals. Additionally, the localized, specific burial conditions at the Sacred Animal Necropolis at Saqqara (such as the role of composite objects, wooden funerary items and mass burial SEM-EDX of mummified ibis) were undoubtedly unusual and their effects on the corrosion of objects have not yet been inter- A Hitachi S-3700N Variable Pressure SEM with an Oxford preted fully. INCA Energy system was used for elemental analysis Conservation cleaning of the bronzes has revealed new and mapping. The analyses were run at an accelerating evidence for original surfaces and in some cases original voltage of 20 kV at a pressure of 50 Pa and with a working decorative effects. The remains of contextual evidence, such distance of 10 mm. The detection limits for each element as textile wrappings found on objects, were left undisturbed are variable but typically 0.1–0.3%. The relative precision to ensure their preservation, even though this has the effect (reproducibility) is about 2% for the major elements, 10% that details of the original surfaces may still be obscured. As for concentrations in the 5–20% range and deteriorates as part of a general programme of improving storage across the detection limits are approached. the Museum, unsuitable storage media have been replaced. It is hoped that a proportion of the cleaned objects are now more accessible by those interested in the many bronzes from this site. Following cleaning some objects may now ACKNOWLEDGEMENTS be considered suitable for inclusion in the permanent registered study collections of the Department of Ancient Egypt The authors would like to thank Dr Jeffrey Spencer, deputy keeper in and Sudan. the Department of Ancient Egypt and Sudan, for his permission to

81 QUANYU WANG, HE HUANG AND FLEUR SHEARMAN take samples for metallographic study. Thanks are also due to Ingrid 10. Paterakis, A.B., ‘The influence of conservation treatments and Gerritsen who worked on the Saqqara material during her internship environmental storage factors on corrosion of copper alloys in at the Museum in 2008. the ancient Athenian Agora’, Journal of the American Institute for Conservation 42 (2003) 313–339. 11. Scott, A.D., Metallography and microstructure of ancient and historic metals, Getty Conservation Institute, Los Angeles (1991). AUTHORS 12. Wang, Q. and Ottaway, B.S., Casting experiments and microstructure of archaeologically relevant bronzes, BAR International Series Quanyu Wang ([email protected]) is a scientist and 1331, Archaeopress, Oxford (2004). 13. Wang, Q., Metalworking technology and deterioration of Jin bronzes Fleur Shearman ([email protected]) a conservator, from the Tianma-Qucun site, Shanxi, China, BAR International both in the Department of Conservation and Scientific Research. Series 1023, Archaeopress, Oxford (2002). He Huang ([email protected]) was an intern in the same 14. Cowell, R.M., ‘Scientific appendix I: chemical analyses’, inCata- department in 2007–2008 and is currently a conservator in the logue of Egyptian antiquities in the British Museum: VII tools and Research Laboratory for Conservation and Archaeology, Shanghai weapons I: axes, ed. W.V. Davis, British Museum Press, London Museum. (1987) 96–118. 15. Ogden, J., ‘Metals’, in Ancient Egyptian materials and technology, ed. P.T. Nicholson and I. Shaw, Cambridge University Press, Cambridge (2000) 148–176. 16. Gettens, R.J. and Frondel, C., ‘Chalconatronite: an alteration REFERENCES product on some ancient Egyptian bronzes’, Studies in Conserva- tion 2 (1955) 64–75. 1. Davies, S. and Smith, H.S., The Sacred Animal Necropolis at North 17. Gettens, R.J., ‘Mineral alteration products on ancient metal objects’, Saqqara: the Falcon Complex and Catacomb: the archaeological in Recent advances in conservation, ed. G. Thomson, Butterworths, report, Egypt Exploration Society, London (2005). London (1963) 89–92. 2. Spencer, J., Department of Ancient Egypt and Sudan, the British 18. Fabrizi, M., Ganiaris, H., Tarling, S. and Scott, D.A., ‘The occur- Museum, personal communication, 30 October 2007. rence of sampleite, a complex copper phosphate, as a corrosion 3. Tennent, N.H. and Baird, T., ‘The identification of acetate efflo- product on copper alloy objects from Memphis, Egypt’, Studies in rescence on bronze antiquities stored in wooden cabinets’, The Conservation 34 (1989) 45–51. Conservator 16 (1992) 39–43. 19. Paterakis, A.B., ‘Corrosion of archaeological bronze by acetic Metal 07: Interim Meeting of the ICOM-CC Metal WG 4. Thickett, D. and Odlyha, M., ‘Note on the identification of an acid’, in Amsterdam, unusual pale blue corrosion product from Egyptian copper alloy’, ed. C. Degrigny, R. van Langh, I. Joosten and Studies in Conservation 45 (2000) 63–67. B. Ankersmith, Rijksmuseum, Amsterdam (2007) 94–99. 20. Wang, Q., ‘Identification of blue corrosion on silver head vase 5. Paterakis, A.B., ‘The hidden secrets of copper alloy artifacts in the British Museum CDS analytical request No. Athenian Agora’, in Metals 2001: Proceedings of the International (1962,1212.1)’, AR2007/60, British Museum, London (2007) (unpublished). Conference on Metals Conservation, ed. I.D. MacLeod, J.M. Theile 21. Bradley, S. and Thickett, D., ‘The pollutant problem in perspec- and C. Degrigny, Western Australian Museum, Welshpool (2004) tive’, in Indoor air pollutants: detection and mitigation of carbonyls 232–236. (1998): http://iaq.dk/iap/iap1998/1998_05.htm (accessed 14 May 6. Trentelman, K., Stodulski, L., Scott, D., Back, M., Stock, S., Strahan, 2009). D., Grews, A.R., O’Neill, A., Weber, W.H., Chen, A.E. and Garrett, 22. Paterakis, A.B., University College London, personal communica- S.J., ‘The characterization of a new pale blue corrosion product tion, 17 November 2008. Studies in Conservation found on copper alloy artefacts’, 47 (2002) 23. Selwyn, L.S., Binnie, N.E., Poitras, J., Laver, M.E. and Downham, 217–227. D.A., ‘Outdoor bronze statues: analysis of metal and surface 7. Oddy, W.A. and Hughes, M.J., ‘Stabilization of “active” bronze and samples’, Studies in Conservation 41 (1996) 205–228. Studies in iron antiquities by the use of sodium sesquicarbonate’, 24. Shearman, F., ‘Patina and polychromy: reconstructing some tech- Conservation 15 (1970) 183–189. nical histories for small Egyptian bronze sculpture in the British 8. Horie, C.V. and Vint, J.A., ‘Chalconatronite: a by-product of Museum’, in Decorated surfaces on ancient Egyptian objects: tech- conservation?’, Studies in Conservation 27 (1982) 185–186. nology, deterioration and conservation, ed. J. Dawson, C. Rozeik 9. Pollard, A.M., Thomas, R.G. and Williams, P.A., ‘Mineralog- and M. Wright, Archetype Publications, London (forthcoming). ical changes arising from the use of aqueous sodium carbonate 25. Madsen, H.B., ‘Benzotriazole: A perspective’, in Corrosion inhibi- solutions for the treatment of archaeological objects’, Studies in tors in conservation, UKIC Occasional Paper 5, ed. S. Keene, UKIC, Conservation 35 (1990) 148–152. London (1985) 19–21.

82 An unfinished Achaemenid sculpture from Persepolis Tracey Sweek and St John Simpson

Summary During the conservation of an Achaemenid relief showing two grooms (British Museum 1825,0421.4: ME 118839) it was realized that the fragment had both a finished and an unfinished groom within the same carved panel. This relief is a fragment of part of the external façade of the north staircase of the monumental Apadana at Persepolis and dates from about 500–480 bc. A study of the carving marks on the finished and unfinished portions provided insights into the sequence in which the reliefs at Persepolis were carved and the tools used at each stage. The similarities and differences in the two figures illustrate the degree to which the individuality of the sculptor is evident in a scheme that was rigidly designed and laid out. The seemingly incomplete carving is also considered in the context of the vast scale of the carvings at the Apadana and the likelihood that the unfinished parts would have been masked, at least in part, by polychromy.

INTRODUCTION with three other sculptures. It was placed on display shortly afterwards in one of the west-facing recesses along the east Persepolis is one of the greatest sites of ancient Iran and was wall of the Grand Central Saloon, immediately adjacent to added to the Unesco list of World Heritage Sites in 1979. A the present doorway from the Great Court opposite the great deal of research on Achaemenid stone-working and Rosetta Stone [7; p. 176]. The adjacent recesses were used the sculptors and sculptures at the site has already been to exhibit nine other sculptures from the same site that published by Nylander [1; pp. 22–72, 2], Tilia [3, 4] and had been presented by the Earl of Aberdeen in 1818 and Roaf [5] from the 1960s. The purpose of this contribu- Sir Gore Ouseley in 1825. These recesses also displayed an tion is to present a technical study of a partially completed early series of Persepolis casts that had been made in c.1825 sculpture in the British Museum collections and to compare by the British East India Company Resident in Bushehr, these results with the observations of others made at the Lieutenant-Colonel Ephraim Gerrish Stannus, which had site. At the time of writing, the sculpture considered here been presented to the British Museum in 1827 by his superior forms part of the display in the Rahim Irvani Gallery for officer and Governor of Bombay, Mountstuart Elphinstone Ancient Iran, which opened in June 2007. [8]. These pieces all remained here until a reorganization of the displays in 1865, after which they were redisplayed first at the west end of the Assyrian Transept (where the Balawat Gates are currently exhibited [9; p. 80]), and later in the HISTORY refurbished upper gallery dedicated to ancient Iran. The sculpture of the two grooms is well known in the Sculpture 1825,0421.4 (ME 118839) is an Achaemenid relief modern literature connected with antiquarian researches showing two grooms that was found at Persepolis during at Persepolis and the early development of collections from excavations carried out in 1811 by Sir Gore Ouseley’s ancient Iran in the British Museum [10; p. 60; Plates XV.1 mission to the Court of Persia, and was probably discov- and XVIII.2 (No. 1), 11; p. 52 and Plate XXIIe, 12; p. 69; ered during April or May of that year when his secretary Cat. 23]. Barnett was the first to reconstruct its original posi- James Morier initiated digging and “brought to light several tion by comparison with the more completely preserved east beautiful sculptures” [6; p. 238]. It was published in illustra- stairway of the Apadana and proved that it belonged to the tion soon after its discovery by his elder brother, Sir William uppermost register on the east wing of the north stairway Ouseley [6; Plate XLVI (bottom centre)] and was presented of this building [10]. These two grooms were, therefore, part by Sir Gore Ouseley to the British Museum in 1825 along of a procession of grooms either carrying saddle cloths (as

83 TRACEY SWEEK AND ST JOHN SIMPSON

figure 1. Two grooms relief (British Museum 1825,0421.4: ME 118839)

here) or escorting horses and followed by two charioteers, of unsightly debris along the northern front of the Apadana” and accompanied by ushers and guards. [15; p. 70]. Further fragments from this section were found Construction of the Apadana was initiated by Darius I during Schmidt’s excavations, together with glazed bricks (reigned 522–486 bc), probably in the early fifth century bc, deriving from the north east tower of the Apadana. These and completed by his son and successor Xerxes I (reigned suggest that it was the collapse of the high mudbrick struc- 486–465 bc); it remained an important integral part of the ture behind it that had brought down the parapet and thus complex until the destruction of Persepolis by Alexander created the local stratigraphy [15; pp. 70–71 and Figure 22, in 330 bc. The destruction of the wooden ceiling must 16; Figure 16]. have precipitated the collapse soon afterwards of the high Closer visual examination of this stretch of façade mudbrick walls that framed this monumental columned confirms that there are three distinct zones of weathering. hall, and this process buried the lowermost two-thirds of The uppermost corresponds to the weathered section of the north stairway and adjacent façade and entirely covered Ker Porter’s illustrations [17]. Below this there is a central the equivalent east stairway. The latter was only revealed and less weathered portion, and along the bottom a paler during excavations by the Oriental Institute, Chicago in unweathered section that corresponds to the strip cleared the early 1930s, but the uncovering of the north stairway by Schmidt. The uppermost section was never buried and its occurred over a longer period, beginning in the early nine- erosion reflects the passage of some two and a half millennia, teenth century [13]. whereas the central zone was first exposed during excava- The first records of the north stairway were published in tions carried out in 1811 by Sir Gore Ouseley’s mission the eighteenth century [14]. They prove that by this period and continued in July the same year by his attaché, Robert the faces of the second register were already exposed and Gordon [18]. These differential horizontal weathering lines were not only rather weathered but also showed clear traces illustrate one of the major challenges to the present-day of systematic iconoclasm; furthermore, there were no in situ preservation of the in situ sculptures at the site and provide remains of the top register, which, unlike the lower sections a useful dated timeline of the process of decay [19]. of the terrace, had been constructed as a free-standing – and therefore proportionally more vulnerable – parapet. Most of the north façade was then cleared down to the waist level of the third register by the second quarter of the DISCUSSION: THE RELIEF nineteenth century. It was during this activity that many fragments belonging to the uppermost register were recov- The fragment showing the two grooms currently meas- ered, but the lowermost section was only finally excavated ures 45 cm high, 78 cm across and is 12 cm deep: it weighs in the 1930s when Schmidt refers to “the removal of a strip approximately 60 kg, Figure 1. One face is carved to repre-

84 AN UNFINISHED ACHAEMENID SCULPTURE FROM PERSEPOLIS sent the upper portions of a pair of grooms walking to the right and holding saddlecloths and whips. They are depicted in so-called ‘Median dress’ of a rounded cap and a knee- length belted tunic worn over trousers. There is a roughly vertical line running between the two figures, to the left of which the details are finished, whereas to the right only the outlines have been ‘roughed out’. The line running between these two figures perhaps refers to a predetermined point of division between two sets of craftsmen. The relief in question came to the Museum’s stone conservation studios for conservation prior to its display in the 2005 temporary exhibition Forgotten Empire [12]. It figure 2. Detail of the ‘step’ in the stone indicating the division was during this period of conservation that the opportu- between the finished and unfinished grooms nity arose to examine the relief in detail and to explore the techniques used in its carving. As well as important details concerning its execution, this also revealed that part of the A detailed study of the distribution of mason’s marks carved sculpture was never completed. This phenomenon along the different sculptures in situ indicates the organi- is not uncommon and at Persepolis unfinished areas of zation of the workforce into separate teams, that different carving to the sculptures have been thoroughly documented sections were carved simultaneously and that the same [3]. However, the opportunity presented by this sculpture in teams worked on both stairways at the Apadana [5; p. 64]. the British Museum was for both curator and conservator The team of carvers would remove the bulk material and to work together to examine the carving in close detail and rough out the shape of the figures, leaving the master carver document it meticulously. to finish the important details such as the heads. It is also The initial observation was a ‘step’ in the stone that divides known that these teams left a reference to their work by the two grooms: this runs in a vertical line bisecting the scribing a mason’s mark (a carved symbol or shape identi- figures; it has a depth of approximately 1 mm (and possibly fying the sculptor or carver) on the surface of the relief. This more in some areas of the unfinished carving), Figure 2. The was not only a form of signature to their achievements as it unfinished groom is located on the proper left side of the additionally indicated where one team would follow on from relief and the finished groom on the proper right. Further another. However, the present relief lacks any mason’s mark examination of the panel highlighted how the unfinished that might attribute it to a particular team or sculptor. groom was part of an earlier phase of the carving that would The stone used to construct Persepolis was sourced finally produce the finished groom, Figures 3–6. from local quarries close to the site, a pale grey limestone

figure 3. The unfinished groom figure 4. The finished groom

85 TRACEY SWEEK AND ST JOHN SIMPSON

figure 5. The unfinished arm of the right groom figure 6. The finished arm of the left groom from the Middle Cretaceous period and another darker grey denser limestone from the Upper Cretaceous period [3; p. 76]. Limestone fresh from the quarry is known as ‘green’, a terminology that has a parallel in fresh sapwood from a tree. When stone is first removed from the ground it retains more moisture within its structure and is thus easier to carve; as the stone matures and is exposed to the elements it becomes much harder and develops a patina, making it more difficult to carve. Typical practice in preparing to carve a block of stone is to map the desired design onto the surface; at Persepolis it is thought that this task was carried out by a designer [1; p. 33, 3; p. 83]. Following a design of the figures and patterns set out and planned by the designer, a team of stone carvers would begin working on a section of the panel. So that each mason would have the space to work comfortably and figure 7. Detail of the chisel marks to surface of unfinished groom uninhibited by neighbouring colleagues, it was necessary to carve the figures out of sequence. The selection of tool was governed by the depth of material to be removed and at Persepolis teams of carvers were employed to remove depth by Tilia [3; p. 91]. The chisel marks on the unfin- the bulk material; for this they would select and use either ished surface are wide, flat and appear haphazard in their a point or punch. Following this process, a tool referred to application. The upper proper left corner of the fragment as a claw chisel or toothed hammer would be employed to shows evidence of a fine-toothed tool, possibly a hammer even out the surface to a roughly textured level. It was only chisel, Figure 7 [3; p. 91]; the configuration of these tooth after this stage that flat chisels of various diameters were indents to the surface indicates a tapping action, striking used to give a smooth finish [1; p. 33, 5; p. 3]. In essence the stone with a hammer at an obtuse angle. This would these techniques are still applicable today. discount a claw chisel having been used to chase away the In the case of the British Museum relief, a wide, flat excess material, as a series of parallel ‘tram lines’ would chisel or hammer has been used to rough out the unfin- then be evident. To the lower proper left edge there is ished groom. It was at this final stage of the work that an area of tool marks indicating the use of a point; the the master carver or sculptor would have taken over using gouges in the stone here are long and parallel, the exact fine, flat chisels to carve the facial features and details of pattern left by a tool removing bulk material, Figure 8. the relief. The desired smooth surface was attained by The tool used to complete the facial features and details of using a variety of methods and may have been achieved the finished groom appears to be a small, fine chisel, and by polishing with an abrasive or stones [1; p. 32, 3; p. 83]. this tool has also been used to emphasize the outline of the Some of these techniques can be seen on sculpture details to the face and figure, Figures 4 and 6. The practice 118839, including the roughing out of the proper left of cutting into the planes of the background was used to figure (Figure 5); this phase of carving is described in emphasize depth through creation of a shadow line. This

86 AN UNFINISHED ACHAEMENID SCULPTURE FROM PERSEPOLIS is commonplace in the execution of sculpted wall reliefs, and must have been particularly effective when these were placed in an external setting where bright sunlight cast strong shadows. In exploring the finished groom it is worth examining details such as the precisely carved spiral curls that appear in neat, uniform diagonal rows. In comparison, on the unfinished groom a number of the curls have been set out in a blocked section by carving neat raised roundels that show the phase prior to completion, Figure 3. An additional contrast between the two figures can be found in the belt. The carving of the belt on the unfinished groom has figure 8. Detail showing the use of a point chisel to rough out the surface of the stone been left incomplete in a manner that suggests some inter- ruption in the process, Figures 7 and 9; Figure 6 shows the completed belt on the finished groom. It is interesting to observe that although the stone carvers at Persepolis adhered rigidly to the designs that had been set out for the reliefs, there were still opportuni- ties to apply their own touches and interpretations to the figures. In studying the Apadana reliefs these subtle differences can be seen in details such as the facial features and the hairstyles. Finally, it might be added that the thickness of this relief is not original but reflects a deliberate attempt to thin the sculpture, probably for transport from the site in the nineteenth century. The same is true of other fallen sculptures removed from the site during this period [18; p. 49]. There is a vertical crack through the leading figure that had previously been crudely reinforced on the reverse, again probably in the nineteenth century, using a figure 9. Detail of the incomplete belt of the unfinished groom lead strip, brick fragments and plaster. There had also been extensive previous overpainting across the face, apparently to render the background similar to other fragments applied to the sculptures and would, therefore, have covered with iron staining and lichen. This overpainting concealed missing carved details [4, 21, 22]. It is in its isola- continued across earlier lettering that commemorated tion from Persepolis that the irregularities in the sculpture the gift of this relief by Sir Gore Ouseley and, therefore, of the two grooms have become apparent, highlighting the presumably derives from a later phase of display, perhaps various phases of carving. The finished groom has been in the 1930s. Some additional traces of light blue paint completed to a polished quality, the unfinished groom noted along the bottom edge are thought to derive from displays at least three or four stages in the execution of an earlier refurbishment of the galleries. Such traces are the carving: initial roughing out with a point; levelling of by no means uncommon on sculptures that have been areas of the background with a toothed hammer; shaping on frequent display and, while they offer a glimpse into of the groom with a flat tool; and finally carving the detail changing fashions and colour schemes within museums, with a fine chisel. What has become clear in studying the they also illustrate the need for caution when attempting information offered by the reliefs of the Apadana is that to interpret the original polychromy on sculptures [20]. the sculptors were not of equal ability or dexterity and that the standard of carving is varied, yet this has not detracted from the overall vision left by the sculptors at Persepolis. It is not simply a matter of unfinished and finished areas, but CONCLUSIONS also that within this enormous project there is a human element that manifests itself in the unfinished reliefs. The unfinished reliefs found at Persepolis are challenging and there are many scenarios to explain why the carvings remained incomplete. The simple answer may lie in the vastness of the site and the magnitude of the task ACKNOWLEDGEMENTS of its construction; within the scale of Persepolis, these unfinished details would have been a minor element in The authors thank Trevor Springett, who made the images for this the overall scheme, particularly as paint was extensively study.

87 TRACEY SWEEK AND ST JOHN SIMPSON

AUTHORS 10. Barnett, R.D., ‘Persepolis’, Iraq 19 (1957) 55–77. 11. Mitchell, T.C., ‘The Persepolis sculptures in the British Museum’, Iran Tracey Sweek ([email protected]) is a conservator in 38 (2000) 49–56. Forgotten empire: the world of ancient the Department of Conservation and Scientific Research and St John 12. Curtis, J. and Tallis, N. (eds), Persia Simpson ([email protected]) is a curator in the , British Museum Press, London (2005). Department of the Middle East, both at the British Museum. 13. Simpson, St J., ‘Pottering around Persepolis: observations on early European visitors to the site’, in Persian responses: political and cultural interaction with(in) the Achaemenid Empire, ed. C. Tuplin, Classical Press of Wales, Swansea (2007) 343–356. 14. Sancisi-Weerdenburg, H. (ed.), Persepolis en Pasargadae in wisse- lend perspectief. Iraanse oudheden beschreven en getekend door REFERENCES Europese reizigers, Phoenix, Groningen/Leiden (1989). Persepolis I: structures, reliefs, inscriptions Ionians in Pasargadae: studies in Old Persian archi- 15. Schmidt, E.F., , Oriental 1. Nylander, C., Institute Publications, Chicago (1953). tecture , Boreas (Uppsala Studies Ancient Middle and Near Eastern 16. Herzfeld, E., ‘Rapport sur l’état actuel des ruines de Pérsepolis et Civilisations, 1), Uppsala (1970). propositions pour leur conservation’, AMI 1 (1929/30) 17–64. Archeologia Classica 2. Nylander, C., ‘The toothed chisel’, 43 (1991) 17. Ker Porter, R., Travels in Georgia, Persia, Armenia, ancient 1037–1052. Babylonia, etc. etc. during the years 1817, 1818, 1819, and 1820, 3. Tilia, A.B., ‘A study on the methods of working and restoring stone Longman, Hurst, Reed, Orme and Brown, London (1822). and on the parts left unfinished in Achaemenian architecture and 18. Curtis, J., ‘A chariot scene from Persepolis’, Iran 36 (1989) 45–51. East and West sculpture’, 18 (1968) 67–95 and Figures 1–148. 19. Mohammadi, P. and Krumbein, W., ‘Biodeterioration of ancient 4. Tilia, A.B., Studies and restorations at Persepolis and other sites stone materials from the Persepolis monuments (Iran)’, Aerobio- of Fárs, Istituto Italiano per il Medio ed Estremo Oriente, Rome logia 24 (2008) 27–33. (1972). 20. Ambers, J.C. and Simpson, St J., ‘Some pigment identifications for 5. Roaf, M., ‘Sculptures and sculptors at Persepolis’, Iran 21 (1983) objects from Persepolis’ (2005) www.achemenet.com/ressources/ 1–164. enligne/arta/pdf/2005.002-Ambers-Simpson.pdf (accessed 25 6. Ouseley, W., Travels in various countries of the East; or more partic- March 2009). ularly Persia, 3 vols, London (1819–1823). 21. Nagel, A., ‘The colours of Achaemenid Persepolis: new research 7. Report to the Trustees of the British Museum (1865) on the polychromy of Achaemenid sculpture and architecture, (unpublished). c.520–330 bce’, in Memorial volume for A. Shapur Shahbazi, ed. 8. Simpson, St J., ‘Bushehr and beyond: some early archaeological K. Abdi, Tehran (forthcoming). discoveries in Iran’, in From Persepolis to the Punjab: 19th-century 22. Nagel, A., ‘Aspects of non-verbal communication in Persepolis: discoveries, ed. E. Errington and V.S. Curtis, British Museum the polychromy of Achaemenid Persian sculpture, c.520–330 bce’, Press, London (2007) 153–165. in Les arts de la couleur en Grèce ancienne. Productions antiques, 9. A Guide to the Exhibition Galleries of the British Museum, reproductions modernes et contemporaines, ed. P. Jockey, BCH Bloomsbury, Trustees of the British Museum, London (1884). supplement (forthcoming).

88 Scientific investigation of pottery grinding bowls from the Archaic and Classical Eastern Mediterranean Michela Spataro and Alexandra Villing

Summary Pottery mortaria, or grinding bowls, are found in most early cultures around the Mediterranean. As with most plain, utilitarian household pottery, archaeologists often believe them to be locally produced and of too little value to be objects of trade. In order to test this view and to distinguish production centres and technological traits, petrographic analyses of thin sections and measurements of elemental composition using scanning electron microscopy with energy dispersive X-ray spectrometry were carried out on examples from several sites. These included pieces from recent excavations in the East Greek city of Miletos (Turkey) as well as from Al Mina in Syria, Lachish in Judah (Israel) and the Greek trading post of Naukratis in Egypt, all in the British Museum’s collections. In addition, several groups of reference material were analysed. Overall, 61 ceramic objects, mostly mortaria dating to the seventh–fifth century bc, were analysed. The results revealed that Cyprus was a major production centre for mortaria and that its products were widely traded in the Eastern Mediterranean, not only to the Levant but also to East Greece. The results also suggest further production centres, including locations in the Egyptian Nile Delta and at Miletos, and the use of different clay recipes in the production of the same shape.

INTRODUCTION The study presented here applies such collaborative research to another functional item of ancient household In the ancient Mediterranean world, plain, undecorated pottery: the mortar, or mortarium. Mortaria are shallow domestic pottery was ubiquitous in any household and open bowls, usually around 30 cm in diameter, some- makes up the majority of finds in most archaeological exca- times made from stone, wood or metal, but mainly in vations. Usually presumed to be locally produced, slow to pottery; they are found in most civilizations around the change in shape, and not subject to trade, it is, therefore, Mediterranean from the late eighth century bc until Roman perceived to be of little scholarly interest. Only recently times. Strong traces of abrasion (scratches, smoothing, and has its potential begun to be recognized; cooking pots in inclusions exposed or removed) indicate that they were particular have become popular objects of research, being used for grinding and mashing substances with the help of a conceived of as markers of technological and social change, wooden pestle, Figure 1. It is known from ancient texts and as indicators for ethnic or cultural association, but also as representations that the ground substances were primarily highly specialized commodities of trade [1–3]. An example foodstuffs, which were processed into spicy sauces, cereal of the latter are the carefully burnished cooking pots of gruels and vegetable mashes; other materials could also Aigina, made from local volcanic clay and highly resistant be ground in mortaria, including medicinal mixtures or to thermal shock, that were popular export items in the pigments [8]. Greek Mediterranean over many centuries [4–7], and that The starting point for this investigation was the study were imitated closely by Classical Athenian potters. Exami- of still-unpublished finds from recent excavations in the nations of this kind have been made possible by increasingly seventh–fifth-century bc levels of the East Greek city of sophisticated methods to investigate pottery scientifically, Miletos (Figure 2) [9], which was an important political, as well as by the wider acceptance in Classical archaeology economic and cultural centre within the Greek and wider of these methods as effective complements to traditional Mediterranean world. Among the pottery excavated from archaeological and art-historical methods. the habitation quarter and sanctuaries was an exceptional

89 MICHELA SPATARO AND ALEXANDRA VILLING

variety of different types of mortaria, Figure 3. One type, present throughout the seventh and sixth centuries bc, which is represented by over 400 fragments that make up about one quarter of all mortaria from the site, stands out from the rest on account of its unusual yellow-buff colour. It is typically of truncated conical shape with a thickened, more or less oval rim, a slightly wavy/rippled outside and a smooth inside. Morphologically it resembles another group of Milesian mortaria in brown clay, but the closest parallels, for both shape and clay, seem to be mortaria from other sites in the Eastern Mediterranean region, and particularly from Cyprus and Palestine. They include examples in the British Museum’s collections from the Greek trading posts of Naukratis in Egypt and Al Mina in Syria. For some of the pieces from Naukratis, neutron activation analysis (NAA) has recently suggested Cypriot as well as local production [8, 10]. Examples of this type (and of a related ring-footed type) from Palestine have also been identified in recent archaeometric studies as mostly Cypriot or North Syrian as well as possibly East Greek imports [11; pp. 198–200, 12; pp. 79–82, 13; pp. 19–20, 14; pp. 141–142, 15]. As a consequence, several questions emerged regarding the examples from Miletos:

• Are the flat-based mortaria local Milesian products or figure 1. Greek terracotta figurine of a monkey using a mortarium and were they imported? pestle, made in Corinth c.400 bc (British Museum GR 1903,0518.4) • Why does the type appear in so many places (was it

figure 2. Locations of the sites discussed in the text

90 SCIENTIFIC INVESTIGATION OF POTTERY GRINDING BOWLS FROM THE ARCHAIC AND CLASSICAL EASTERN MEDITERRANEAN

produced in one place, or made in several places in a METHODS AND SAMPLING similar manner)? • Is there any indication that the specific function of Samples of 52 mortaria, mostly dating to the seventh–fifth mortaria (i.e. grinding) occasioned the use of special century bc, were selected for petrographic analysis from clay fabrics and pottery technology for this shape? five sites located along the eastern Mediterranean coast- line, Figure 2: Miletos; the city of Xanthos in Lycia; the In order to answer these questions, typological studies of the Greek trading post of Naukratis in the Egyptian Nile Delta; shapes and visual examination of the clays alone were not Al Mina, the Greek/Phoenician trading post and port of the sufficient. In particular, it was impossible to decide whether neo-Hittite kingdom of Unqi in Syria; and the Judean city of the yellow-buff clay of the Milesian mortaria, which seemed Lachish, Figures 3 and 4. Sampling encompassed mortaria unusual for Miletos but was paralleled at other sites, was due with a wide range of stylistic and typological features and to a single production centre exporting its wares or to the fabrics, but particular emphasis was placed on the group of exploitation of local sources of buff clay in a variety of places flat-based mortaria in buff clay. especially for this particular shape. Progress could be made In addition to mortaria, samples were taken from only by scientific analysis of the clay fabrics in question. other objects for which the place of manufacture can be

figure 3. Photographs and profile drawings of mortaria from Miletos and Naukratis: M5 (Miletos K92.958.1); M4 (Miletos K86.32.20); M10 (Miletos K91.306.3); M15 (Miletos K86.201.3); M17 (Miletos Z04.9.13); N1 (Naukratis, British Museum GR 1886,0401.80); N4 (Naukratis, British Museum GR 1886,0401.81); and N12 (Naukratis, British Museum GR 1910,0222.15)

91 MICHELA SPATARO AND ALEXANDRA VILLING

figure 4. Photographs and profile drawings of mortaria from Al Mina and Lachish: AM1 (Al Mina, British Museum ME 1995,1223.2); AM4 (Al Mina, British Museum ME 1995,1223.1); L2 (Lachish, British Museum ME 1980,1214.10348); L4 (Lachish, British Museum ME 1980,1214.10281); and L6 (Lachish, British Museum ME 1980,1214.10283) inferred on archaeological grounds so as to establish refer- and normalized. The five analyses for each sample were aver- ence groups for Cypriot and Milesian clays. Samples were aged, which was reasonable as the results did not show signif- taken from a typical Cypriot basket-handled amphora and icant differences. three Cypriot terracotta figurines found at Miletos, from a Principal component analysis (PCA) was used to interpret likely Cypriot basket-handled amphora from Lachish, and the EDX results and to help in the identification of chemical from three locally produced cooking pots and a pithos-like groups based on the concentration of the oxides. The PCA vessel from Miletos. Extensive analyses of Milesian pottery analysis was performed using the Microsoft Excel plug-in were moreover available in the form of Seifert’s study of Biplot 1.1 [17], with column data centred and standardized. Milesian amphorae by X-ray diffraction, X-ray fluorescence Only the first two components were extracted. The inclusion and optical microscopy [16]. or omission of particular samples and elements, as well as the These samples were analysed using two complemen- choice of which components to extract, strongly affects the tary techniques: petrographic analysis of thin sections (61 resulting scatter plots and their interpretation is inherently samples) and scanning electron microscopy (SEM) used subjective. Nevertheless, chemically similar samples will in combination with energy dispersive spectrometry X-ray cluster in the same region of each scatter plot, reflecting the analysis (EDX; 28 samples), Table 1. Both techniques are abundance of various elements in the samples and allowing necessary to identify the differences and similarities among the petrographic grouping to be compared to a clustering samples in terms of quantitative and qualitative composition. based on elemental composition. Petrographic analysis of ceramic thin sections can be used to This contribution does not present all the data and results identify mineral inclusions, which are then compared to the from this study, but instead focuses on the research meth- geological setting of the study area with the aim of locating odology and the results that relate to the flat-based, buff potential sources of clay and other raw materials, and thus the mortaria from Miletos and elsewhere, helping to place them most likely centre of production for each fabric. Elemental within the framework of patterns of production, technology analysis allows the identification of the elemental composi- transfer and trade in the Eastern Mediterranean. tion of the fabrics, in particular the matrix, which is mainly composed of clay minerals that are too fine to be studied in thin section with the polarized light microscope. Elemental analysis was carried out using a Hitachi S-3700 RESULTS AND DISCUSSION SEM in combination with an Oxford Instruments INCA EDX analyser. Five bulk analyses were conducted for each Petrographic analysis sample at a magnification of 90= on an area of c.1.4 = 1.0 mm that included matrix and temper. The results for 11 elements Among the 61 samples from five sites that were studied, 31 (Na, Mg, Al, Si, P, K, Ca, Ti, Mn, Fe, Zn) were quantified, clay fabrics were identified. The greatest variety of clay fabrics converted into oxide percentages (oxygen by stoichiometry) was found in the assemblage from Miletos, from which 33

92 SCIENTIFIC INVESTIGATION OF POTTERY GRINDING BOWLS FROM THE ARCHAIC AND CLASSICAL EASTERN MEDITERRANEAN MnO FeO 2 with standard deviation reported in parentheses; the detection limit was 0.1–0.3% limit the detection in parentheses; reported deviation standard with O CaO TiO 2 K 5 O 2 P 2 SiO 3 O 2 O MgO Al 2 Na Al Mina AM1AM3AM4Miletos M3 1.20 (0.10)M4 1.40 (0.12)M14 1.65 (0.09) 6.87 (0.53)M16 5.59 (0.22)M17 1.31 (0.17) 7.32 (0.20)M25 13.36 (0.51) 1.14 (0.16)M26 1.89 (0.12) 12.63 (0.42)M27 3.18 (0.27) 15.56 (0.24) 6.63 (0.27) 52.87 (2.08)M28 1.59 (0.36) 5.70 (0.28) 52.75 (1.28)M29 2.08 (0.19) 2.09 (0.09) 59.67 (0.38) 13.36 (0.22)M30 3.33 (0.44) 1.96 (0.36) 0.17 (0.11) 14.14 (0.49)M31 5.09 (1.17) 0.83 (0.21) 15.75 (0.99) 0.32 (0.06)M32 3.61 (0.14) 1.99 (0.24) 52.28 (0.53) 16.06 (0.93) 0.15 (0.08)M33 2.58 (0.31) 0.87 (0.12) 52.29 (1.15) 2.44 (0.28) 15.27 (2.75) 66.74 (2.11)Naukratis 0.93 (0.28) 1.40 (0.16) 2.35 (0.18) 13.16 (0.38) 61.95 (2.68)N1 1.74 (0.39) 0.13 (0.13) 1.14 (0.14) 3.21 (0.22) 20.95 (0.55) 16.07 (1.06) 59.44 (7.09)N4 1.89 (0.26) 0.25 (0.08) 0.70 (0.21) 13.89 (3.46) 0.44 (0.23) 18.03 (1.01) 54.69 (0.15)N10 5.47 (0.28) 1.25 (0.12) 19.63 (0.44) 0.34 (0.06) 1.93 (0.28) 61.68 (1.04)N12 5.84 (0.28) 5.03 (0.40) 16.51 (0.92) 0.68 (0.12) 0.30 (0.15) 1.40 (0.11) 77.22 (5.67)N13 7.14 (0.21) 13.67 (0.19) 4.29 (0.30) 0.67 (0.08) 1.96 (0.19) 0.30 (0.04) 65.30 (1.72)N14 6.46 (0.24) 17.10 (0.78) 13.37 (0.58) 2.43 (0.63) 1.54 (0.21) 0.30 (0.17) 68.08 (2.38) 0.78 (0.09)N15 17.48 (1.11) 1.55 (0.09) 0.04 (0.08) 15.98 (0.23) 1.81 (0.44) 0.22 (0.20) 56.36 (0.70)Xanthos 4.52 (0.59) 1.60 (0.14) 0.11 (0.06) 13.29 (0.66) 5.67 (0.36) 1.04 (0.10) 0.03 (0.07) 52.96 (1.79)X1 0.74 (0.17) 7.62 (1.02) 1.88 (0.11) 6.19 (0.32) 3.50 (0.43) 0.26 (0.05) 0.11 (0.06) 52.81 (0.19) Lachish 0.75 (0.11) 4.37 (0.46) 6.20 (0.36) 8.45 (1.90) 3.95 (0.15) 1.97 (0.44) 0.18 (0.09) 51.25 (1.03) 12.52 (0.47) 19.84 (0.53)L2 0.57 (0.14) 2.82 (0.07) 6.23 (0.23) 0.85 (0.11) 1.96 (0.14) 0.24 (0.16) 0.13 (0.07) 13.30 (0.27)L4 0.59 (0.09) 2.92 (0.16) 1.22 (0.30) 2.50 (0.29) 6.53 (0.16) 17.75 (0.67) 0.27 (0.09) 0.10 (0.08) 0.78 (0.20)L7 6.71 (0.20) 0.38 (0.15) 49.93 (0.81) 2.05 (0.28) 12.50 (0.14) 0.20 (0.09) 0.59 (0.12) 1.45 (0.04) 0.04 (0.04) 5.53 (1.86) 3.17 (0.42) 51.50 (1.27) 1.44 (0.14) 13.23 (0.54) 6.48 (0.21) 0.06 (0.04) 54.80 (0.85) 0.91 (0.12) 4.02 (0.88) 1.50 (0.20) 11.08 (0.64) 6.74 (0.20) 0.09 (0.05) 1.32 (1.02) 13.69 (0.45) 54.39 (0.90) 0.43 (0.15) 0.23 (0.10) 1.43 (0.20) 0.09 (0.03) 5.44 (0.11) 15.89 (1.11) 3.71 (0.30) 0.67 (0.05) 17.46 (1.67) 60.80 (1.43) 0.69 (0.09) 0.26 (0.12) 4.42 (0.61) 0.20 (0.16) 0.05 (0.02) 12.33 (0.39) 1.25 (0.12) 53.38 (1.96) 0.73 (0.05) 7.17 (3.36) 4.29 (1.67) 0.69 (0.12) 1.10 (0.15) 0.02 (0.02) 18.92 (0.53) 1.84 (0.08) 12.92 (0.31) 56.04 (2.60) 4.55 (0.05) 7.41 (0.37) 0.72 (0.08) 0.94 (0.18) 0.08 (0.04) 1.91 (0.15) 1.63 (0.05) 6.75 (0.29) 0.78 (0.05) 4.96 (0.68) 0.81 (0.36) 0.12 (0.02) 13.89 (6.89) 20.58 (1.05) 52.90 (1.28) 0.13 (0.03) 1.53 (0.07) 4.08 (1.15) 0.63 (0.07) 0.21 (0.20) 16.02 (0.29) 17.62 (0.56) 0.17 (0.13) 1.97 (0.22) 5.38 (0.83) 12.88 (0.27) 12.80 (0.55) 0.21 (0.09) 51.65 (2.07) 1.83 (0.13) 5.03 (0.30) 18.24 (1.03) 0.63 (0.11) 0.26 (0.06) 6.25 (0.35) 0.17 (0.06) 48.79 (0.92) 2.78 (0.07) 0.69 (0.06) 6.61 (0.14) 9.91 (0.78) 54.48 (1.44) 0.74 (0.13) 17.54 (2.70) 8.16 (0.31) 0.16 (0.12) 1.22 (0.10) 0.40 (0.08) 1.78 (0.10) 11.07 (1.29) 6.45 (0.09) 0.31 (0.07) 0.13 (0.05) 1.44 (0.23) 0.34 (0.09) 0.10 (0.07) 0.54 (0.07) 1.83 (0.75) 18.07 (0.88) 0.13 (0.12) 6.33 (0.21) 0.71 (0.09) 3.20 (0.13) 6.85 (0.31) 0.14 (0.08) 2.60 (0.31) 6.01 (0.82) 21.96 (4.28) 0.29 (0.04) 0.64 (0.07) 6.46 (0.33) 17.75 (1.30) 0.13 (0.04) 17.03 (0.82) 6.79 (0.05) 0.52 (0.24) 3.65 (0.12) 0.16 (0.05) 0.75 (0.04) 6.88 (1.68) 0.69 (0.12) 0.15 (0.10) 6.33 (0.23) 0.02 (0.05) 0.12 (0.03) 4.27 (1.62) 5.04 (1.42) 5.71 (0.32) table 1. Compositional data derived from EDX analyses. The results are the mean of five bulk analyses carried out on each sample sample on each out carried analyses bulk five of mean the are results The analyses. EDX from derived data 1. Compositional table and the reproducibility 1–2% the reproducibility and

93 MICHELA SPATARO AND ALEXANDRA VILLING sherds were analysed. These included samples that can be The three Cypriot terracotta figurines showed two assumed to have been produced locally (Archaic cooking different fabric types: one is vitrified and very fine-grained, pots and a pithos storage jar), samples that were almost with some fine quartz, occasional calcareous fragments, certainly imported to the site from Cyprus (Archaic terra- some iron oxides, small quantities of chert, igneous inclu- cotta figurines and an amphora), and the mortaria, Figure sions, serpentine and pyroxene; the second is fossiliferous 3. and coarser. The geology of Cyprus is highly distinctive Two of the cooking pots have very micaceous pastes, rich and varied, with the Troodos ophiolite complex (Pre- in coarse sub-angular schist fragments, biotite and musco- Campanian) in the centre, the Pentadaktylos succession in vite (Figures 5a and 6), whereas a third cooking pot is rich the north, the Circum Troodos sedimentary succession in in micas and amphibole. All three cooking pots contain as the north east and south, and the Mamonia complex in the temper sand rich in coarse minerals and rock fragments south [20]. Although the inclusions in the figurines are very from either metamorphic or volcanic formations and were fine, it is possible that they come from the Troodos outcrops, low-fired; the lack of vitrified pastes indicates that the firing which are rich in ophiolite and volcanic sediments (basalt, temperature never exceeded 850°C [18; p. 431]. This specific dolerite, and lava) and radiolarian shales [21]. The fabric of choice of non-calcareous clays tempered with metamorphic, the basket-handled amphora, derived from mafic bedrock, volcanic rock fragments might have been for thermal shock is similar to that of the Cypriot figurines. resistance purposes, since this recipe had been known in Most of the Archaic flat-based buff mortaria from Europe since Neolithic times [7]. The fabric is consistent Miletos (Figure 3; M4, M5 and M10) are made from two with the geological setting of Miletos, with volcanic tuff fabric types, each with vitrified and very fine pastes that around the site and outcrops of gneiss, mica-schist, dolerite, are much finer than the other mortaria types. One group basalt and amphibolite about 10 km north east and less than is micritic and vitrified, with scarce inclusions, mainly of 20 km north west of the site [19; Figure 5.1]. very fine quartz, muscovite mica, occasional metamorphic

figure 5. Micrographs of: (a) a Milesian cooking pot (sample M26), showing fragments of mica-schist and clusters of lamellae of muscovite mica; (b) a flat-based buff mortarium (sample M3) from Miletos; (c) a flat-based buff mortarium from Naukratis (sample N7); and (d) a sample (L2) of a ring-footed buff mortarium from Lachish. In each case, the width of the image is 3.5 mm

94 SCIENTIFIC INVESTIGATION OF POTTERY GRINDING BOWLS FROM THE ARCHAIC AND CLASSICAL EASTERN MEDITERRANEAN

An example is M16, a Hellenistic spouted mortarium, the fabric of which is very similar in visual appearance to locally produced Bronze Age pottery at Miletos. Petrographic examination shows that it is isotropic, slightly micritic and micaceous, with abundant poorly sorted quartz, muscovite, plagioclase and occasional biotite, and a few igneous inclusions (most probably basalt). Similar clay from a metamorphic environment was also used to produce Milesian amphorae in the Archaic period [16; p. 36 and Figure 16]. Finally, the coarse fabric of sample M14 (a flat-based mortarium) is micritic, micaceous and isotropic, with abundant coarse and poorly sorted quartz, some muscovite, plagioclase, and a little chert and pyroxene. Although the paste is burnt and its matrix cannot easily be described, it is unlike the paste of the flat-based buff mortaria, and figure 6. SEM image (90=) of a sample of a Milesian cooking pot (M26), showing large mica-schist fragments and clusters of musco- does not contain rock fragments comparable to those in vite mica the fabrics of the cooking pots and painted mortaria such as M17. The flat-based buff mortarium from Xanthos has a fine and silty paste with calcareous pellets and very small rock fragments or chert and, very rarely, tiny fragments amounts of chert, muscovite and pyroxene. This compo- of serpentine, Figure 5b. The second contains more abun- sition shows some similarities with those of the Cypriot dant fine rounded microcrystalline calcareous fragments, terracotta figurines and the basket-handled amphora found very occasional microfossils and coarser mineral grains. at Miletos. They are petrographically similar to the Cypriot terra- Of the 15 mortaria analysed from Naukratis, nine cotta figurines, and even though formations similar to the Archaic flat-based buff mortaria (some of which had been Troodos outcrops occur elsewhere in the Greek/Eastern identified as Cypriot imports by neutron activation anal- Mediterranean region, a Cypriot origin for the Milesian ysis (NAA): Figure 3; N1 and N4) have a very fine micritic flat-based buff mortaria is quite possible. One further fabric, extremely similar to the vitrified type from Miletos sample could also come from Cyprus (as it is very rich in and also that from Al Mina (see below), with some fine radiolarian chert and flint) but it was produced with a very quartz, and occasional igneous inclusions and chert, Figure different recipe, in which flint was probably deliberately 5c. added to the clay. Previous work on the Nile clay and mixed Nile/marl clay The fabrics of the Archaic painted mortaria from Miletos pastes from New Kingdom pottery produced at Amarna (Figure 3; M17) are much coarser than the flat-based and Memphis shows the presence of limestone, some plant buff mortaria. Their fabric is slightly calcareous and remains, mica, feldspars and microfossil inclusions [22]. micaceous, with fine and well-sorted sub-angular quartz, These minerals and inclusions do not seem to match the some coarse rounded microcrystalline micritic fragments, flat-based yellow-buff mortaria found at Naukratis, rein- muscovite and occasional biotite micas, rare opaque forcing the suggestion that these mortaria were imported. minerals, some rounded mudstone and abundant sub- In contrast, a mortarium of the same shape but made of angular to sub-rounded coarse fragments of metamorphic a browner clay (Figure 3; N12) that had been identified by quartz-rich rock. In contrast to the flat-based buff mortaria, NAA as of Egyptian manufacture [10; p. 70], and a post- which do not contain added inclusions, they were prob- Archaic mortarium of a different shape, show fabrics that ably tempered with metamorphic sand rich in mica-schist are more ferruginous and contain many angular iron-rich that was also added to the Milesian cooking pot fabric, and inclusions and coarse pyroxene fragments. Since the site of which is abundant around Miletos. Naukratis is located in the Nile Delta on alluvial deposits Two other mortaria (M15 and M16) were made from that are transported by the river over long distances [23, 24; clay originating from the same medium-grade metamor- p. 165 and Figure 9.2], these minerals could have come via phic environment, but (as the inclusions are smaller and the Nile from a number of places, and their absence in the less angular) from sources located farther from the orig- pottery from Memphis and Amarna does not exclude the inal outcrop. A flat-based mortarium (Figure 3; M15) looks possibility of mortaria production at Naukratis. much like the buff mortaria in shape, but it differs from The three Archaic flat-based buff mortaria from Al them in being made of brown clay. It belongs to a large Mina (Figure 4; AM1) are microscopically similar to those group of such flat-based brown mortaria that sometimes belonging to the same type from Miletos and Naukratis, with feature a thin white coating. a very fine micritic and vitrifiedpaste, occasional inclusions Several other less common mortarium shapes have fabrics of chert, radiolarian chert, plagioclase, fine muscovite and similar to the cooking pots and to the painted mortaria. pyroxene, and a small number of fine serpentine and felsic

95 MICHELA SPATARO AND ALEXANDRA VILLING rock fragments. In contrast, two flat-based mortaria of a Figure 7 shows that the bulk analyses from different sherds different morphological type typically made of a reddish are very similar, which indicates that most samples have a clay (Figure 4; AM4) show two different fabrics: one is non- homogeneous paste, suggesting that their clays were fine micritic and very micaceous with red clay fragments; the and well mixed; only the painted mortarium M17, which is other is blackened by burning, very micritic, with abundant coarser than the other specimens, shows some ‘outliers’. quartz, iron oxides, calcareous fragments, and a little chert. To the left of Figure 7 lies a cluster that includes all the It is difficult to suggest a provenance for this type of fabric cooking pots and the pithos (M26–M29) that are assumed because these minerals are common to many different to be locally produced. The clustering of the samples is of geological environments. The site of Al Mina lies near the interest because the cooking pots were subdivided into three northern Syrian border, at the estuary of the Orontes River fabrics by petrographic examination, and the pithos was and the surrounding area has greenstone, metamorphic attributed to a fourth with shale as opposed to mica-schists, and volcanic rocks in a geology that is very similar to that amphibole and dolerite. However, the EDX results suggest on the island of Cyprus. Serpentine outcrops are present that their overall elemental composition is similar, rich in in this northern region of Syria [25], making it difficult aluminium, potassium and silicon and low in calcium and to distinguish Cypriot imports from locally or regionally magnesium (Table 1), reinforcing the impression (based on produced pottery using petrographic analyses. typology as well as petrographic examination) that these Of the six ring-footed mortaria from Lachish in Israel, samples are of local production. all of which date to the Persian period (fifth–fourth century The flat-based yellow-buff mortaria (M3 and M4) cluster bc), five (of which two are illustrated in Figure 4; L2 and with the Cypriot basket-handled amphora (M30) and the L6) are made from a clay fabric which is fossiliferous, Cypriot terracotta figurines (M31–M33) on the right side micritic, rich in microfossils and calcareous fragments, of Figure 7. They have similar elemental composition, with some serpentine and basalt inclusions, Figure 5d. The with high percentages of magnesium and calcium. The sixth sample (from the mortarium illustrated in Figure 4; Hellenistic spouted mortarium (M16) and a burnt flat- L4) is rich in dolomitic sand. based mortarium (M14) – possibly a kiln waster – seem to These results seem to match Master’s petrographic be local, because they cluster well with the cooking pots. description of two mortaria from the site of Ashkelon [14; The coarse-tempered painted mortarium (M17) does not pp. 110 and 113], which mentions fossiliferous and calcar- fit either cluster, even though it contains mica-schist that is eous fabrics with peridotite (in stages of serpentinization) typical of the local geology. and basalt fragments. Master suggests that this group (‘cate- Elemental analysis also suggests a similarity with the gory 9’) might come from the Cypriot Troodos formation Cypriot figurines for the mortarium from Xanthos (X1), [14; p. 134]. Indeed, local production seems very unlikely, Figure 8. From the mineralogical and elemental results it as serpentine is not present in the outcrops surrounding the would seem that the flat-based yellow-buff mortaria found Tell, even though Lachish is located in a fossiliferous and in Ionia and Lycia were imported from Cyprus, while a calcareous setting [26; p. 2569 and Figures 36.34 and 36.35, version of this type made in brown clay, painted mortaria, 27]. On the other hand, a quarry for dolomitic sand in the cooking pots and the pithos-like vessel (M14, M16 and outcrops east of Lachish in the Judean Mountains around M26–M29) were produced locally by Milesian potters. Jerusalem, appears to be the source for the clay of the sixth The elemental composition of the seven mortaria from mortarium; this material was exploited for pottery manu- the Greek trading post of Naukratis in Egypt analysed facture in the Middle Bronze Age [28; pp. 263–264]. On the by EDX (pink in Figure 8) reflects the grouping identi- basis of the regional geology, it is possible to suggest a distant fied by optical microscopy reasonably well. The flat-based source for five of the six ring-footed mortaria studied, and yellow-buff mortaria (N1, N4) have high positive PC1 possibly a regional production site for the sixth. values, as do the other objects thought to have been made The fabric of the amphora from Lachish is different to in Cyprus. NAA had already suggested that many Archaic those of the mortaria: it is a mixture of non-micritic and flat-based mortaria from Naukratis are Cypriot imports micritic clays with a much lower percentage of micritic [10; p. 70], a conclusion supported by this study. Although fragments, serpentine and igneous inclusions, and a higher petrographically different, the flat-based mortarium (N10) percentage of muscovite and chert. This suggests that the five and Corinthian ‘tile fabric’ mortarium (N15) [8; p. 33 and mortaria not produced locally and the amphora might come Figure 10] have similar PC2 values that are both more from a similar geological background, although the potters negative than that for the Egyptian marl mortarium (N12), exploited two different clay sources and techniques. which is a contemporary local version of the flat-based type that Mommsen et al. have already attributed to Egyptian manufacture using NAA [10; p. 70]. This Egyptian marl EDX analyses mortarium is fairly similar to a mortarium of different and later type (N13), with which it shares high PC2 values and In total, 14 samples from Miletos were analysed by EDX in a comparable petrography, suggesting that the manufacture the SEM. Initially, each of the five bulk analyses per sample of mortaria in the region persisted into later, post-Archaic was considered separately in PCA, Figure 7 and Table 1. periods.

96 SCIENTIFIC INVESTIGATION OF POTTERY GRINDING BOWLS FROM THE ARCHAIC AND CLASSICAL EASTERN MEDITERRANEAN

figure 7. Principal component analysis of EDX results from samples found at Miletos, first and second components (PC1, horizontal axis, 39% variance; PC2, vertical axis, 16% variance). Each symbol represents one of the five bulk analyses for each sample. Different colours represent the different samples and the symbol shape indicates typology

figure 8. Principal component analysis of EDX results from all the samples discussed in this paper, first and second components PC1,( horizontal axis, 34% variance; PC2, vertical axis, 16% variance). Each symbol represents the mean of five bulk analyses for each sample. Different colours indicate the site at which the sample was found (green = Miletos, blue = Al Mina, red = Lachish, pink = Naukratis and purple = Xanthos). The symbol shapes indicate typology

97 MICHELA SPATARO AND ALEXANDRA VILLING

The EDX analyses of the samples from the trading post of Al Mina in Syria (blue in Figure 8) show that the elemental composition of sample AM3 and perhaps also of AM1, both regular flat-based buff mortaria, are similar to those of the other flat-based yellow-buff types from Naukratis (N4), Miletos (M3 and M4) and Xanthos (X1), and to those of the Cypriot terracotta figurines (M31–M33), all of which have high positive PC1 values. In contrast, the flat-based ‘red’ mortarium (AM4) has a negative PC1 value, suggesting a different clay source with a lower calcium oxide content. Even though the flat-based yellow-buff mortaria from Al Mina are slightly coarser and richer in micritic pellets than those from Miletos, the results suggest that they could all come from a similar source. The association with the Cypriot material also suggests that this source is more figure 9. SEM image (90=) of a sample of a flat-based buff mortarium likely to be Cyprus than the region of Al Mina itself, which, from Naukratis (sample N1), showing a very fine highly fired structure as suggested above, would have been a possibility on the with fine mineral inclusions basis of petrographic examination alone. At Lachish in Palestine, the EDX results (red in Figure 8) suggest that sample L2, a ring-footed mortarium from the Cypriot reference material, aided the association of samples same petrographic group as three other samples, does not with likely Cypriot, Milesian and other origins. Earlier NAA fit particularly well within the cluster of ‘Cypriot imports’. on some of the samples indicated a Cypriot origin for many Petrographic differences have also been observed in the of them, and also helped to pinpoint an Egyptian centre of different pastes used in the Lachish mortaria, which are of production [8, 10]. Conversely, the petrographic analyses a later date than the likely Cypriot imports from Al Mina, anchored within the main group of likely Cypriot imports Miletos and Naukratis. Even though there are certain simi- two flat-based buff mortaria (N5 and N6) from Naukratis larities, the Lachish samples are fossiliferous and contain that earlier NAA had classified as separate and distinct [8; coarser minerals than those present in the other Cypriot pp. 41–42]. imports. Nevertheless, they might come from Cyprus, and In addition to suggesting provenance, a number of tech- the elemental analyses are reasonably close to those for the nical observations can also be made. The typical Cypriot flat- Cypriot cluster. Sample L4, for which petrographic analysis based buff mortaria were manufactured using a very specific had suggested production in Israel, appears not to belong to recipe, employing finely levigated clay, which is fine-grained this cluster, while amphora L7 could fit in the Cypriot cluster and slightly micritic from a serpentine formation. Most of as it shows a similar elemental composition to the probable the fabrics of the flat-based Cypro-Phoenician type mortaria Cypriot products, with relatively high magnesium, calcium were vitrified, indicating that the mortaria were fired at and sodium, and low silicon and aluminium. high temperatures, exceeding 850°C, Figure 9. The final As these results demonstrate, the integrated use of product had a well-defined shape with a hard paste, which complementary scientific techniques can provide a wider was difficult to break, giving the vessels a long service life. picture of the history of these archaeological objects than The Cypriot ring-footed mortaria from Lachish were fired at would otherwise be possible. The study of the thin sections lower temperatures, as testified by the abundance of micritic allowed the different fabrics of the mortaria to be identified, pellets and microfossils, and have coarser inclusions, with characterizing the minerals and the size and shape of the serpentine and pyroxene probably added deliberately as a particles, which indicate whether they were added by the sand temper. Their fabric is nevertheless tough and sturdy, potters as temper or were naturally present in the clay. This with the inclusions quite possibly aiding effective grinding. method was useful for the analyses of the Milesian cooking Since similar clay recipes were also used for amphorae and pots and the painted mortaria, where the clays were heavily terracotta figurines, it is hard to judge the much-debated tempered with sand. In particular, this type of analysis issue of to what extent the materials were dictated by tradi- allowed the identification of the coarse basalt inclusions tion or by the specific technological choices made to enhance and the microfossils characteristic of the Lachish ceramics. the functionality of the mortaria [29, 30]. Undoubtedly, On the other hand, some fabrics, such as those of some flat- however, the fabric was highly suited to its purpose, and the based yellow-buff mortaria, are too fine to be differentiated wide distribution of Cypriot mortaria seems to suggest that using polarized light microscopy, and additional methods customers appreciated this functionality. are necessary to describe differences or similarities between Local imitations that copied the shape and manufac- groups and to suggest potential provenances. In this study, turing technique of the Cypriot flat-based mortaria, but elemental analysis of thin sections by EDX was used to using different and often coarser clays, were produced both group samples on the basis of their elemental composition. in Miletos and Naukratis. In both places, however, the local The resulting clusters, which also included Milesian and products failed to match the quality and functionality of the

98 SCIENTIFIC INVESTIGATION OF POTTERY GRINDING BOWLS FROM THE ARCHAIC AND CLASSICAL EASTERN MEDITERRANEAN

Cypriot mortaria; the Milesian and Naukratite brown flat- Naso and Jonathan Tubb. They also thank the Leverhulme Trust for based mortaria examined were both fired below 850°C and a research grant (RF/6/RFG/2008/0510). Kate Morton supplied the generally appeared softer and less sturdy. In due course local drawings in Figures 3 and 4. potters began to manufacture grinding bowls of different and distinctly local shapes, such as those with added spouts. This may have been in part a response to specific local culinary needs, and was achieved by adapting local clay recipes AUTHORS that had been in use for other shapes. Such seems to be the Michela Spataro ([email protected]) is a scien- case with the sixth-century bc painted, ring-footed mortaria tist in the Department of Conservation and Scientific Research and from Miletos, the fabrics of which are reminiscent of some Alexandra Villing ([email protected]) a curator in the Milesian cooking pot fabrics. Department of Greece and Rome at the British Museum.

CONCLUSIONS REFERENCES

Three main observations emerge. First, Cyprus was identi- 1. Joyner, L., ‘Cooking pots as indicators of cultural change: a petrographic study of Byzantine and Frankish cooking wares from fied as a major production centre for mortaria throughout Corinth’, Hesperia 76 (2007) 183–227. the Archaic period, trading its products not just to Palestine 2. Birney, K., ‘Tracking the cooking pot à la steatite: signs of Cyprus but also to the East Greek region. Second, local copies were in Iron Age Syria’, American Journal of Archaeology 112 (2008) made of this common import in Miletos, Naukratis and, 565–580. 3. Ben-Shlomo, D., Shai, I., Zukerman, A. and Maier, A.M., ‘Cooking it seems, Palestine, followed by the development of more identities: Aegean-style cooking jugs and cultural interaction in distinctly local types. Third, many different clay recipes were Iron Age Philistia and neighboring regions’, American Journal of used to manufacture mortaria-shaped vessels, but among Archaeology 112 (2008) 225–246. 4. Lindblom, M., Marks and makers: appearance, distribution and these it is the Cypriot mortaria that possessed a superior function of Middle and Late Helladic manufacturers’ marks on Aegi- functionality due to the clay paste and firing regime used. netan pottery, Studies in Mediterranean Archaeology CXXVIII, The wide distribution of Cypriot mortaria in the Eastern Paul Astroms Förlag, Jonsered (2001). Mediterranean for several centuries from around 700 bc 5. Klebinder-Gauß, G., Keramik aus klassischen Kontexten im Apollon-Heiligtum von Ägina-Kolonna. Forschungen in Alt-Ägina onwards must be seen in the context of an increasingly inter- , Verlag der Österreichischen Akademie der Wissenschaften, connected Mediterranean with far-reaching trade routes Vienna (forthcoming). along which travelled not only staples of daily life and luxury 6. Tite, M.S. and Kilikoglou, V., ‘Do we understand cooking pots goods but also new culinary practices. It suggests the exist- and is there an ideal cooking pot?’, in Modern trends in scientific analysis of ancient ceramics ence of a distinct Eastern Mediterranean koine with regard , ed. V. Kilikoglou, A. Hein and Y. Maniatis, BAR International Series 1011, Archaeopress, Oxford to food processing technology that crossed the boundaries (2002) 1–8. of several civilizations. But the spread of culinary practices 7. Spataro, M., ‘Pottery technology and manufacture at the Korenovo and other social and cultural factors alone cannot explain Culture (LBK) site of Malo Korenovo (Bjelovar, Croatia)’, Opus- cola Archaeologica the widespread and continued popularity of these plain, 27 (2003) 49–61. 8. Villing, A., ‘“Drab bowls” for Apollo: the mortaria of Naukratis utilitarian household vessels. The observations reported and exchange in the Archaic Eastern Mediterranean’, in Naukratis: here suggest that, at least in part, it was their superior func- Greek diversity in Egypt, ed. A. Villing and U. Schlotzhauer, British tional qualities that made Cypriot mortaria so attractive Museum Press, London (2006) 31–46. Stadtgrabungen und Stadtforschung to customers in Ionia, Lycia and Palestine, and the trading 9. Graeve, V. von, ‘Milet’, in im westlichen Kleinasien - Geplantes und Erreichtes, Byzas 3, ed. posts of Naukratis and Al Mina. W. Radt, Ege Yayınları, Istanbul (2006) 241–262. Like cooking pots, pottery mortaria appear to constitute 10. Mommsen, H., Fletcher, P., Hook, D., Schlotzhauer, U., Villing, another category of household pottery where a specific vessel A., Weber, S. and Williams, D., ‘Neutron activation analysis of Naukratis: function could influence the choice of clay fabric and tech- pottery from Naukratis and other related vessels’, in Greek diversity in Egypt, ed. A. Villing and U. Schlotzhauer, British nology, and where a superior product made in specialized Museum Press, London (2006) 69–76. workshops found a wide distribution, even across cultural 11. Bennett, W.J. and Blakely, J.A., Tell El-Hesi: the Persian period borders. (Stratum V), Eisenbrauns, Winona Lake (1989). 12. Fantalkin, A., ‘Mezad Hashavyahu: its material culture and historic background’, Tel Aviv 28 (2001) 3–165. 13. Mazar, A. and Panitz-Cohen, N., Timnah (Tel Batash) II. The finds from the first millennium bce, Qedem 42, Jerusalem (2001). The seaport of Ashkelon in the seventh century ACKNOWLEDGEMENTS 14. Master, D.M., bce: a petrographic study, PhD dissertation, Harvard University, University Microfilms International Dissertation Publishing, Ann The authors are grateful to Ahmet Aydemir, Caroline Cartwright, Arbor (2001). Volkmar von Graeve, Jan-Marc Henke, Evangelia Kiriatzi, Gudrun 15. Yellin, J. and Artzy, M., ‘Ceramic provenance: NAA’, in The Ma’agan Klebinder-Gauß, Richard Macphail, Pamela Magrill, John Meadows, Mikhael ship 2, ed. Y. Kahanov and E. Linder, Israel Exploration Nigel Meeks, Andrew Middleton, Hans Mommsen, Alessandro Society and University of Haifa, Jerusalem (2004) 221–228.

99 MICHELA SPATARO AND ALEXANDRA VILLING

16. Seifert, M., Herkunftsbestimmung archaischer Keramik am Beispiel 25. Carte géologique de l’Afrique / Geological Map of Africa, Sheet 3, von Amphoren aus Milet., BAR International Series 1233, Archaeo- 1: 500,000, Association des services géologiques africains – press, Oxford (2004). Unesco, Paris (1963). 17. Smith, E.P. and Lipkovich, I.A., Biplot 1.1. Statistics Department, 26. Horowitz, A., ‘Notes on the geology of the Lachish area’, in The Virginia Tech (1999–2002). renewed archaeological excavations at Lachish (1973–1994), 18. Rice, P.M., Pottery analysis: a sourcebook, University of Chicago Vol. 5, ed. D. Ussishkin, Tel Aviv University – Sonia and Marco Press, Chicago (1987). Nadler Institute of Archaeology Monograph Series 22, Emery 19. Crouch, D.P., Geology and settlement: Greco-Roman patterns, and Claire Yass Publications in Archaeology, Tel Aviv (2004) Oxford University Press, Oxford (2004). 2569–2574. 20. Geological Map of Cyprus, Geological Survey Department, 27. Golik, A., ‘On the geology of the Ziklag area, Israel’, Bulletin of the Government of Cyprus, 1: 250,000, D. Couvas & Sons Ltd, Research Council of Israel 9G (1960) 129–134. Limassol (1979). 28. Goren, Y., Finkelsten, I. and Na’aman, N., Inscribed in clay: prov- 21. Geological Survey Department, Ministry of Agriculture and enance study of the Amarna Letters and other ancient Near Eastern Natural Resources and Environment, Republic of Cyprus, texts, Tel Aviv University – Sonia and Marco Nadler Institute of www.moa.gov.cy/moa/gsd/gsd.nsf (accessed 10 March 2009). Archaeology Monograph Series 23, Emery and Claire Yass Publi- 22. Bourriau, J.D., Smith, L.M. and Nicholson, P.T., New Kingdom cations in Archaeology, Tel Aviv (2004). pottery fabrics: Nile clay and mixed Nile/marl clay fabrics from 29. Livingstone Smith, A., ‘Processing clay for pottery in northern Memphis and Amarna, Egypt Exploration Society Fourteenth Cameroon: social and technical requirements’, Archaeometry 42 Occasional Publication, London (2000). (1) (2000) 21–42. 23. Bernedo, A.V.B., Neutron activation analysis of ancient Egyptian 30. Feathers, J.K., Schiffer, M.B., Sillar, B., Tite, M.S., Kilikoglou, pottery, DPhil dissertation, University of Manchester (1988) V. and Vekinis, G., ‘Comments on M.S. Tite, V. Kilikoglou and (unpublished). G. Vekinis, “Review article: strength, toughness and thermal 24. Said, R. (ed.), The geology of Egypt, Published for the Egyptian shock resistance of ancient ceramics, and their influence on tech- General Petroleum Corporation, Conoco Hurghada Inc. and nological choice”, Archaeometry 43(3) (2001), 301–24, and reply’, Repsol Exploracion, S.A. by A.A. Balkema, Rotterdam (1990). Archaeometry 45(1) (2003) 163–183.

100 Establishing best practice in asbestos removal: the management of unique Medieval floor tile assemblages Maureen Mellor and Denise Ling

Summary This paper outlines a proactive response by theBritish Museum to tackle a hazardous substance rather than leave it for a future generation to resolve. A total of 15 tile pavements and panels was removed from the former Medieval tile and pottery room (gallery 43), of which nine had been backed with ‘Asbestolux’ board, an insulation material that contains between 25 and 40% asbestos. These have been decontaminated, with three pavements and three smaller sections having been remounted for display in the new Medieval gallery. All nine are historically very important and unique artefacts, part of a collection of national and international importance; those chosen for redisplay exemplify different aspects and techniques of tile production and design. The technical challenges of ‘remote-control’ conservation through the walls of a protective tent are explored, including the training and monitoring of specialist contractors in conservation skills, while ensuring the safety of the staff. It gives a warning to others of the hazards of past practices, and sets out to show the Museum’s solution to the problem.

INTRODUCTION perous merchants [1; pp. 239–240 and Figure VII (vol. 1), 4, 5] and feature in courtiers’ houses as at Acton Court, near The new Medieval gallery, that opened in spring 2009, Bristol [6; p. 295 and Figure 159] and once discarded these presented an opportunity to redisplay some of the Medieval tiles were resistant to decay and so represent an archive of tile pavements as part of an integrated and themed gallery on material culture that displays both pagan and Christian Medieval Europe, ad 1050–1500. The British Museum holds iconography, preserved for modern scholarship. the best collection of Medieval glazed and decorated earthenware tile pavements in Britain. These reflect the superb artistic innovation of early craftsmen from the twelfth century, and the decorative treatment with their layers of meaning that WHAT CAN TILES TELL US ABOUT A continued to evolve until the sixteenth century [1]. These BUILDING? pavements provided a practical, hard wearing and agreeable surface on which to walk. The plain glazed mosaic pavements Medieval paving tiles are historical documents that make it adopted by the monks in northern England and southern possible to engage with the cartoonists behind their designs. Scotland were probably introduced from Cistercian houses The luxury tiles of Chertsey Abbey, with rare figural depic- in France or Germany where comparable floors were laid tions dating to the second half of the thirteenth century, set [2]. A very different tradition of tile-making was introduced out Arthurian legends including that of the popular romance into southern England in the second quarter of the thir- of Tristram and Isolde [7, 8]. Some of the tile borders teenth century. These circular pavements with inlaid designs included representations of evil, embodied as human-headed were commissioned by Henry III for his chapel at Clarendon grotesques. The later wall panel tiles depicting an archbishop, Palace, Wiltshire. Initially under royal patronage, the inlaid queen and king may have been designed for display in niches tiles with decorative motifs established a new fashion that in an ecclesiastical setting, while the earlier floor tiles are then spread throughout southern England (in, for example, believed to have been destined for a secular royal setting, Muchelney Abbey and Salisbury Cathedral) and beyond [3]. either upstream at Windsor Castle or more probably down- Later tiles with inlaid designs were adopted by a few pros- stream at the Palace of Westminster [9].

101 MAUREEN MELLOR AND DENISE LING

In a royal setting these Medieval paving tiles helped to take the tiles, suggesting that the mosaic pavements were convey power and also communicated educational stories or intended as an integral part of the interior design. The pave- romances. The pavements are ‘signifiers of space’ [10], and ment seen in Figure 1 was part of a large panel containing a give an insight into the wealth of decoration in the private circular pattern, which had been reassembled from loose tiles apartments of the king and queen at Clarendon Palace, a found at Byland Abbey. This arrangement can still be seen favoured hunting lodge [11–13]. The inlaid designs may have in the north chapel of the south transept at Byland Abbey, been copied from pattern books, bestiaries or fine textiles, although the glaze is now very worn. and the alphabetic tiles also suggest that the inner circle of In the later Middle Ages initials, rebuses and insignia the court was literate. could convey the individuality and power of a local abbot, as at Hailes Abbey [16; p.11 and Figure 8], or the symbolic meaning of the Passion (as illustrated at Great Malvern North Yorkshire pavements: Byland and Rievaulx abbeys Priory), reminding people about their beliefs. The icono- graphic dating of these tiles helps to document the history In an ecclesiastical setting these Medieval paving tiles helped of the building and to indicate when refurbishment took create a simple and contemplative environment, to aid medi- place [6; p. 363 and Figure 242]. At the level of the parish, tation, prayers and rituals in the monk’s daily life (liturgical tiles provide an insight into local communities, for example, function). This type of tiling was popular in Cistercian the detailed designs in relief and counter-relief of the leper monasteries in Yorkshire in the thirteenth century, as seen in hospital pavement found in situ at Burton Lazars, the largest the plain glazed mosaic pavements at the abbeys of Byland leper hospital in the country. It originally formed part of and Rievaulx [14, 15].These tile mosaics use the combination the Order of St Lazarus of Jerusalem and was subjected to of different tile shapes with alternating colours to bring out Augustinian rule. From the mid-thirteenth century the the geometry of the design. The type is thought to have devel- master of Burton Lazars also became the master of the Order oped in north west Europe in imitation of coloured Italian in England. Some of the designs include heraldry that links to stone mosaic floors, and the mosaic segments were probably dynastic families, but also to a merchant who may have been made and laid out by monastic tilers. The architectural stone- a patron of the hospital [1; pp. 117–118 and Figure III (vol. work inside the monastery church at Byland was rebated to 1), 16; p. 26 and Figure 29].

figure 1. Plain mosaic pavement from the site of Byland Abbey, North Yorkshire, reassembled from loose tiles, formerly on display in the Medi- eval tile and pottery room: 1947,0505.6339–6722

102 ESTABLISHING BEST PRACTICE IN ASBESTOS REMOVAL

figure 2. Reconstructed circular tiled chapel floor from the king’s apartments at Clarendon Palace assembled from tiles recovered during excavations with plaster gap fills. A lost inscription on the outermost band is reconstructed as Pavimentum Henrici Regis Anglie (the pavement of Henry, King of England); the innermost band is also missing, and its design has been disputed: 1957,1006.various

The king’s and queen’s inlaid tiled pavements from private apartments, Figure 3. The tiles for the king’s pavement Clarendon Palace, Wiltshire could be traced to a kiln near the palace, which was removed from the site in 1964 and reconstructed in the former Medi- Clarendon Palace was a hunting lodge of the Norman kings eval tile and pottery room. and also became a favourite royal residence under Henry II. Henry III (reigned 1216–1272) spent between 3000 and 4000 pounds on the extension and embellishment of its buildings [17]. Labour was much cheaper in the thirteenth century RECENT HISTORY OF THE TILE COLLECTION than today, but this palace was still very costly and these Medieval tiles, which are displayed in the newly refurbished For the past 30 years much of the Museum’s collection of Medieval gallery, are to be enjoyed, while they also provide Medieval tiles could be viewed in the former Medieval tile information about the liturgy, theology, art history, history and pottery room, which was a quarry of information both and archaeology of the Middle Ages. for students of Medieval ceramics and for the interested Scattered tiles found in the vicinity of the king’s cham- public; see [16]. On the upper balcony in this gallery tiles bers were used to recreate the circular patterns, forming part were displayed that showed the many different aspects and of the king’s private chapel on the upper floor, Figure 2. The techniques of tile design and fabrication associated with inlaid pavement with prancing lions and griffins had been individual schools of production between the twelfth and found in situ during excavation of the queen’s ground floor the sixteenth century in Medieval England.

103 MAUREEN MELLOR AND DENISE LING

but it was discovered that they had been backed in the 1970s, when ‘Asbestolux’ board had been used as the mounting material. Asbestos insulation board (AIB), commonly known as Asbestolux, was used by the construction industry throughout the UK from the 1950s until the early 1980s. AIBs typically contain between 25 and 40% asbestos fibre, normally brown asbestos (amosite or grunerite) and/or white asbestos (chrysotile). Given the well-publicized dangers of asbestos, and that amosite has been banned in the UK since 1 January 1986, it is not surprising that Asbestolux does not meet current health and safety legislation [18].1 If the backed tile panels had been left intact, the risk from the Asbestolux board would have been negligible; the risk began only once the tiles were removed from the wall and any mechanical investigative or conservation work was carried out. As the tiles had been adhered to the board using BAL FLEX, a two-part, water-resistant rubber-based wall tile adhesive that needed to be removed mechanically, a strategy was needed to remove and dismantle the asbestos- contaminated Medieval tile pavements; such a strategy was developed and implemented in autumn 2006.

DECONTAMINATION AND CONSERVATION TREATMENT

Preliminary steps

First, conservators searched the web for instances of similar treatments and posted messages on the online conservation forum, Conservation DistList, asking for advice from others who had experience of dealing with asbestos associated with museum objects. However, it proved difficult to find conservators with the level of asbestos training required to carry out this work and the necessary licence. Other museums with similar experiences had used licensed asbestos contractors who had worked in close consultation with conservators. The British Museum had experience of using such contractors on building projects, but not to remove asbestos from objects in the collection. The first stage was to carry out a pilot study in the Medieval tile and pottery room, which had by then been closed, using a licensed asbestos contractor, R & F Insula- tions Ltd. The aim was to develop a safe method for removing the tile pavements from the walls, followed by a safe method figure 3. Part of the ground floor pavement from Queen Eleanor of of decontaminating and conserving those tiles mounted Provence’s chamber, made 1250–1252 and found in situ at Clarendon on Asbestolux board. The health and safety regulations Palace. The original pavement included more tiles in the central panel for working with asbestos required special accommoda- than are currently held by the British Museum: 1957,1204.various tion arrangements, the need to erect an isolation tent, staff protection, asbestos monitoring, decontamination facilities, and short-term ‘asbestos-contained’ and secure storage of the THE DISCOVERY OF ASBESTOS panels. CONTAMINATION A comprehensive risk assessment was undertaken covering all aspects of the project. The project manager at Several of these unique pavements were destined for redis- the British Museum liaised with the health and safety team play in the new Medieval gallery that opened in March 2009, at the London Borough of Camden (the local authority for

104 ESTABLISHING BEST PRACTICE IN ASBESTOS REMOVAL the area), who visited the gallery three weeks before work commenced to ensure all the correct procedures would be followed.

The preparatory stage

To create a working space, some 1200 objects had to be removed from the ground floor and upper floor (balcony) in the gallery and accommodated elsewhere before work on the tile pavements and panels began. All the major tile instal- lations were photographed prior to dismantling, and a risk assessment and conservation assessment were carried out by one of the authors (DL) and a colleague. Once the objects figure 4. Detail of tile pavement with relief and counter relief- in situ from the lower floor had been removed from their cases, stamped decoration found at the leper hospital at Burton Lazars, Leicestershire. These tiles, stamped with a merchant’s mark, the reconstructed Medieval kiln from Clarendon Palace was had friable surfaces, some of which were faced with adhesive and dismantled prior to long-term loan to a new gallery at the nylon gossamer during the process of dismantling the old display: Victoria and Albert Museum. 1947,0505.4660 various

The pilot project

Once the room was empty it was necessary to build a hoarding around the gallery door with suitable signage in order to control access, which was restricted to named people who needed to view the work through the viewing panel in the wall of the enclosure that was built subsequently. The need for relevant staff to have a medical report to verify that they had no respiratory problems was considered, but ultimately deemed unnecessary. To test the methodology a small section of a tile pavement on the upper floor was selected. This comprised inlaid and plain glazed tiles recovered in situ from the chancel of Hale- sowen Abbey in the West Midlands [1; pp. 179–181 and Figure VIb (vol. 1)].Full asbestos protective measures, including the building of an enclosure tent, were implemented. The section figure 5. Some of the Museum’s heavy object handlers and museum of pavement had been supported on brackets concealed by assistants carry the wrapped tile panel into the protective tent; the stud walling, which had to be removed to assess the condi- viewing panel is on the right tion of the Asbestolux board. Many of the tiles had previously been repaired and had areas of restoration. The surfaces of those tiles that looked particularly fragile were faced using Paraloid B-72® (ethyl methacrylate copolymer) and nylon tional damage to Asbestolux board, as this would release gossamer to protect them during removal, Figure 4. asbestos fibres. Unfortunately it proved impossible to cut, Wearing disposable overalls and appropriate masks, the saw or soften the rubber adhesive. The contractors there- Museum’s heavy object handling team and museum assist- fore used flat metal tools which were gently tapped with a ants lifted the pavement off the wall to allow it to be inspected hammer to separate the tile and rubber adhesive from the by the specialist contractor to establish its condition. The Asbestolux board. The thickness of the adhesive (15 mm) contractor then wrapped the panel in polythene to contain allowed the tiles to be removed without the tool coming any fibres during the transfer to the isolation enclosure set into contact with the tiles. Within less than two hours the up nearby, and laid it face down onto a protective ‘foam bed’, contractors had removed all 56 tiles from the Asbestolux Figure 5. board, faster than programmed and raising concerns for the Once the pavement had been isolated the metal frame conservation and curatorial staff about the handling of the was unscrewed. At first it appeared it would prove relatively tiles (see below). Once the asbestos had been removed, the straightforward to cut the rubber adhesive from between tiles were laid out in trays and held in quarantine within the the tiles and the Asbestolux board. This would leave the isolation tent. Asbestolux board intact, which is a requirement of the Health The Asbestolux board was double bagged and tape-sealed and Safety Executive (HSE) legislation that prohibits inten- ready for clearance from the working enclosure. The air in

105 MAUREEN MELLOR AND DENISE LING the enclosure was monitored, together with the area imme- more tile panels, each of which had been constructed slightly diately outside the enclosure. Once the work was complete differently. To maintain continuity and build on experience a full environmental clean of the enclosure was carried out already gained, a member of the R & F Insulations team was and smoke tests conducted to confirm that the seals of the appointed to supervise the project. It was decided that British tent were effective. An air test then carried out by Cavendish Museum conservators would photograph every stage and Laboratories Ltd confirmed that the area was clean and the every process, that the contractors, conservators and curator tent could be dismantled. would communicate regularly using mobile phones and that there would be a weekly meeting in an uncontaminated area to discuss the work in progress. The redesigned isolation tent The main project included viewing panels to allow Museum staff to monitor each stage of treatment. For the main phase, it was agreed that more detailed moni- Health and safety requirements included wearing asbestos toring of the contractors would be required, including a protection suits and air-fed masks, which proved physically consistent evaluation of the contractor’s handling of the tiles exhausting over long periods, Figure 6. After each period and the treatment process. In April 2007, the project manager working in the isolation tent, the contractors used a mobile called a site meeting to introduce the contractors to Museum decontamination unit elsewhere in the Museum; typically staff and to conduct a debrief following the pilot project. work periods were no longer than 90 minutes. In addition, To address concerns from both sides, the contractors were all tools and equipment were swabbed clean before leaving asked to draw up a Gantt chart of the projected work on three the isolation tent to prevent cross-contamination.

figure 6. Specialist asbestos contractors, wearing protective clothing and working in the isolation tent, gently prising the Malvern tiles and the dark grey rubber adhesive backing off the Asbestolux board

106 ESTABLISHING BEST PRACTICE IN ASBESTOS REMOVAL

ASBESTOS ANALYSIS the outer face of the rubber adhesive for SEM examination. A 2 mm thick layer of adhesive was then scraped off and As a precautionary measure a representative number of the back cleaned with a HSE-approved vacuum cleaner to tiles held in quarantine were analysed to confirm that no remove any fibres, thereby eliminating the possibility of asbestos residues were present. The results were not as cross-contamination. A further sample of the adhesive was anticipated, since asbestos residues were identified adhered then taken closer to the surface of the tile. The report on the to the rubber adhesive. Of the 46 tiles sampled, eight were analysis of the 24 samples taken from the 12 tiles confirmed found to have these ‘secondary’ asbestos residues, presumed that once the outermost layer of adhesive had been removed to arise from cross-contamination as the metal tool scraped the asbestos risk was low. against the rubber adhesive and the surface layer of the Asbestolux board. Following discussions with Camden’s Environmental Health Officer, advice was sought from the Principal Inspector at the London office of the HSE. ADDRESSING THE SECONDARY As a result, the Museum approached KAD Environmental DECONTAMINATION Consultancy Ltd, to provide a detailed, costed proposal and programme for the removal of the remaining fibres in The degree of contamination of the adhesive implied that the adhesive residue. It was recommended that scanning each tile would need to undergo an unexpected second electron microscopy (SEM) should be used to determine stage of decontamination that had not been foreseen and the quantity of fibres remaining on the tiles, how they were would therefore have an impact on both the programme embedded and whether fibres remained within cracks or and budget. It was not possible for the R & F Insulations crevices. team to carry out this next level of decontamination, as it A second analysis, designed to test a second decontami- would necessitate working directly on the surface of the nation stage, was implemented in August 2007. One of the tiles. authors (MM) took 12 representative tiles for testing to the Initially, it was hoped that, with appropriate precautions Institute of Occupational Medicine (IOM) in Edinburgh. for health and safety, British Museum conservators might Here the tiles were each unwrapped and placed in a fume treat the more than 3000 tiles after they had been individ- cupboard with an asbestos filter. A sample was taken from ually wrapped and labelled by the contractors within the

figure 7. The numbering system of the individual plain mosaic pavement from Byland Abbey (detail)

107 MAUREEN MELLOR AND DENISE LING isolation area. This, and the idea of engaging a freelance tile the lifting process. Once these large vertical mosaic wall conservator to work at the Museum, proved to be imprac- pavements (Byland: 485 tiles, and Rievaulx: 544 tiles) had tical, so a number of specialists were invited to tender for been removed from the wall and placed horizontal, one of the project, including Heritage Tiles Ltd, who had recently the authors (DL) was able to begin work on the geometric carried out work for the Victoria and Albert Museum. tiles. The surface of each tile was numbered with a remov- After lengthy communication between all parties it was able marker, and the information then transferred to a line agreed that the contaminated pavements could be trans- drawing of each pavement on plastic film, Figure 7. ported to Heritage Tiles in Shropshire for final cleaning. R & F Insulations continued to decontaminate the They would also remount three of the larger pavements, pavements in a sealed enclosure, passing the individu- while British Museum conservators would remount the ally wrapped tiles to conservators for storage in lockable smaller sections (see below), leaving the plain mosaic tiled cupboards in the gallery. Once the primary decontamina- pavement from Rievaulx Abbey to be mounted at some tion work was completed, the Museum was provided with stage in the future. certificates of reoccupation.

Secondary decontamination THE TREATMENT PROCESS In February 2008 all the contaminated tiles were collected Primary decontamination from the Museum for delivery to the studios of Heritage Tiles, Table 1. The treatment of the tiles to remove all the Following the pilot study a similar methodology was backing adhesive took place over a period of six months. adopted for primary decontamination of the remaining Before collecting the treated tiles, the Museum required panels and pavement at the upper gallery level (Malvern, assurance that the cleaning process had been effective, so Wessex and Burton Lazars), which were the first to be a sample of 60 tiles from the Canynges, Hailes and Burton treated when, in June 2007, it was agreed that R & F Insu- Lazars pavements was analysed by Bradley Environmental lations should continue to decontaminate the remaining Consultants in September 2008. Fortunately, on this occa- pavements, Figure 6. sion, no asbestos fibres were detected and the tiles were The complete pavement from Canygnes House, a returned to the Museum for redisplay or storage. merchant’s house in Redcliffe Street, Bristol, originally laid between ad 1480 and 1515,required an isolation tent to be built over the whole pavement of 1499 tiles [16; p. 12 and Figure 9]. The contractors erected a large tent in the body DISCUSSION AND CONCLUSIONS of the room to treat this pavement and the smaller section of pavement from Hailes Abbey. The proactive response by the Museum to tackle a Owing to their complexity (weight, size and position hazardous substance rather than simply wrap these tile above the stairway), scaffolding was necessary to remove the panels and leave the issue for a future generation to resolve, Byland and Rievaulx pavements from the wall. In December owes much to support for the project at a senior level in the 2007 the heavy objects handling staff brought in lifting gear Museum. All nine tile pavements previously mounted on and placed it at the upper gallery level; the scaffolders next Asbestolux have been decontaminated, with three having installed platforms and then other Museum staff aided in been remounted by outside specialists for display in the

table 1. Summary of the pavements treated and redisplayed, including details of numbers of tiles, dimensions and mass Pavement Number Dimensions excluding existing Tile number and type Estimated total of tiles frame (mm) (average mass) mass (kg) Byland Abbey (mosaic) 485 (redisplayed) 1910 (height: h) × 1275 (width: w) 485 × small (300 g) 150 × 40 (thickness: t) Burton Lazars hospital 112 (20 redisplayed) 1510 (h) × 800 (w) × 20–23(t) 112 × medium (600 g) 70 Canynges, merchant’s 1499 5860 (h) × 4090 (w) × 27–30(t) 1499 × large (1200 g) 1800 house, Bristol Hailes Abbey rebus 80 (16 redisplayed) 607 (h) × 610 (w) × 26–30(t) 16 × large (1200 g) 20 Halesowen Abbey 56 570 (h) × 1340 (w) × 30(t) 56 × medium (600 g) 30 King’s, Clarendon Palace, 244 (redisplayed) 2250 (h) × 2110 (w) × 29(t) 81 × large (1200 g) 200 Wiltshire 163 × medium (600 g) Malvern Priory 37 (5 redisplayed) 1093 (h) × 163 (w) × 33(t) 5 × large (1200 g) 6 Queen’s, Clarendon Palace, 196 (redisplayed) 2640 (h) × 1040 (w) × 24(t) 70 × large (1200 g) 160 Wiltshire 126 × medium (600 g) Rievaulx Abbey (mosaic) 544 1200 (h) × 1600 (w) × 33–37(t) 544 × small (300 g) 160

108 ESTABLISHING BEST PRACTICE IN ASBESTOS REMOVAL new Medieval gallery. The choice of which pavements to 3. TileWeb: Paving-tile Watercolours Online, The Parker-Hore Archive Collection of Watercolours of Paving-tiles held in Worcester and redisplay was difficult as all nine are historically signifi- in the Ashmolean Museum, Oxford, http://tileweb.ashmolean. cant. The three chosen illustrate different aspects and tech- museum (accessed 10 March 2009). niques of tile production and design and will be displayed 4. Eames, E., ‘Decorated tile pavements in English Medieval houses’, as part of an integrated and themed gallery, while smaller in Rotterdam Papers II: a contribution to medieval archaeology, ed. sections have been remounted in-house (Hailes, Malvern J.G.N. Renaud, Rotterdam (1975) 7–9 and Figures III–V. 5. Eames, E., ‘The Canynges Pavement’,Journal of the British Archae- and Burton Lazars). ological Association XIV (1951) 33–46 and Figures XXII–XXVI. This contribution has outlined the technical challenges of 6. Marks, R. and Williamson, P., Gothic: art for England 1400–1547, ‘remote-control’ conservation through the walls of a protec- Victoria and Albert Museum. London (2003) 295 and Figure 159. Journal tive tent; training the specialist contractors in conservation 7. Gardiner, J.S. and Eames, E., ‘A tile kiln at Chertsey Abbey’, of the British Archaeological Association XVII (1954) 24–42. skills and monitoring their work fell largely to one of the 8. Poulton, R., Archaeological investigations on the site of Chertsey authors (DL). This marathon task of enabling the public to Abbey: Research Volume of the Surrey Archaeological Society No. view these magnificent Medieval pavements again “while 11, Surrey Archaeological Society (1988). Medieval decorative art ensuring the safety of the staff, gives a warning to others 9. Cherry, J., , British Museum Press, London (1991) 60 and Figure 74. of the hazards of past practices and sets out to show the 10. Richardson, A., ‘Review of “The Medieval Tiles of Wales” by Museum’s solution to the problem” [19]. The procedure J.M. Lewis’, Medieval Archaeology XLV (2001) 414. undertaken by the Museum is one that could be recom- 11. Beaumont James, T. and Gerrard, C., Clarendon: landscape of kings mended to others. , Windgather Press, Bollington (2007). 12. Eames, E., ‘The royal apartments at Clarendon Palace in the reign of Henry III’, Journal of the British Archaeological Association XXVIII (1965) 57–85. 13. Eames, E., ‘A thirteenth-century tile pavement from the King’s Journal of the British Archaeological ACKNOWLEDGEMENTS Chapel, Clarendon Palace’, Association XXVI (1963) 40–50. 14. Ferguson, P. and Harrison, S., Rievaulx Abbey, Yale University The authors are enormously grateful for the support and advice Press, New Haven (1999). received from their colleagues at the British Museum: Rainer Geschke, 15. Stopford, J., Medieval floor tiles of northern England, Oxbow Sue Greetham, Zoe Hancock, Marilyn Hockey, David Saunders, Chris Books, Oxford (2005). Terrey, Ken Uprichard and Jonathan Williams. The photographs in 16. Eames, E., English Medieval tiles, British Museum Press, London Figures 1–3 were taken by John Williams and those in Figures 4–7 (1985). by Denise Ling. 17. Beaumont James, T., The palaces of Medieval England, Seaby, London (1990) 78. 18. The Control of Asbestos Regulations 2006: Statutory Instrument 2006 No. 2739, 13 November 2006, http://www.opsi.gov.uk/si/ si2006/20062739.htm (accessed 10 March 2009). AUTHORS 19. Uprichard, R.K., The British Museum, personal communication (2008). Maureen Mellor ([email protected]) is a former curator in the Department of Prehistory and Europe and Denise Ling (dling@ thebritishmuseum.ac.uk) a conservator in the Department of Conser- vation and Scientific Research at the British Museum. NOTE

1. Current UK regulations bring together the three previous sets of regulations, which covered the prohibition of asbestos, the REFERENCES control of asbestos at work and asbestos licensing. These regulations prohibit the import, supply and use of all forms of asbestos. 1. Eames, E., Catalogue of Medieval lead-glazed earthenware tiles They continue the ban introduced for blue and brown asbestos in in the Department of Medieval and Later Antiquities, 2 volumes, 1985 and for white asbestos in 1999 and also continue to ban the British Museum, London (1980). second-hand use of asbestos products such as asbestos cement 2. Robinson, J., Masterpieces: Medieval art, British Museum Press, sheets and asbestos boards and tiles, including panels that have London (2008) 62–63. been covered with paint or textured plaster containing asbestos.

109 The Middle Bronze Age furniture from Tomb P19 at Jericho: wood identification and conservation challenges Caroline Cartwright, Clare Ward, Jonathan Tubb and Hélène Delaunay

Summary Kenyon’s excavations of Tomb P19 at Jericho revealed wooden furniture and funerary artefacts of high quality that provide an accurate reflection of the esteem in which the individuals buried within it were held. Unusual conditions of desiccation had preserved the tomb’s organic materials, but upon excavation deterioration of the organic remains set in very quickly. Despite considerable problems for wood identification and the study of wood technology caused by deterioration during burial and brought about by the conservation methods and materials used at the time, particularly the liberal application of now-discoloured wax, a variety of timbers has now been securely identified. The most recent conservation assessments and treatments of the Tomb P19 wooden artefacts and furniture are described, including a preliminary assessment of the use of laser ablation to remove the disfiguring wax layer, and the implications of this study for the Jericho material on display in the British Museum are evaluated.

INTRODUCTION funerary items has presented scientific and conservation challenges. The Jericho tell (Figure 1) consists of a large city mound that was occupied from the proto-Neolithic through the Early, Middle and Late Bronze Ages to the Iron Age. It is situated near a spring in the southern Jordan valley, TOMB P19 244 m below sea level and west of the River Jordan. Exten- sive excavations undertaken by Kathleen Kenyon from Tomb P19 had a very large chamber and, in common with 1952 to 1958 revealed domestic housing, fortified struc- many of the Middle Bronze Age tombs, was constructed tures and an extra-mural cemetery [1–7]. The last of these and first used in the preceding Early Bronze IV (EBIV) contained shaft tombs, mostly Early to Middle Bronze Age period (c.2400–2000 bc). Remains of the earlier EBIV in date, many of which, through unusual conditions of burial consisted of a single jar, some bronze scraps and desiccation, had preserved organic materials such as wood, fragmentary human bones that had been pushed to the basketry, fruits and foodstuffs, so that Jericho remains one front of the chamber and covered by an earth ramp. of the best examples in the Levant of this type of organic During the Middle Bronze IIB period (c.1750–1650 bc), assemblage. Kenyon explored 27 shaft tombs of the Middle after a gap of around 300 years, the chamber was reused Bronze Age (c.2000–1480 bc), one of the most impres- to inter seven individuals. These were found arranged sive being Tomb P19 [3; pp. 388–410; Figure 193 and Plate in a row with their heads to the west of chamber. Six of 18:1]. Most of the P19 wooden tomb furniture, human and the skeletons were intact, but one (skeleton E) was much animal bones and accompanying funerary objects are in disarranged, apparently disturbed when the other six were the British Museum collections and have, therefore, been introduced. The excavators concluded, therefore, that two the subject of scientific study and conservation condition phases of burial had occurred within the Middle Bronze assessments. This contribution explores the importance of Age use of the tomb [3]. Of the seven Middle Bronze Age Tomb P19 and how the remarkable survival of the wooden individuals (designated A–G), skeleton E was a female,

111 CAROLINE CARTWRIGHT, CLARE WARD, JONATHAN TUBB AND HÉLÈNE DELAUNAY

figure 1. Jericho tell. Image: Jonathan Tubb

aged about 28 years and around 1.55 m tall who was said robber’ hypothesis was correct, all these should be assigned to be “powerfully built”. Three of the remaining six skeletons to individual E, since it does not seem likely that robbers were male: skeleton B, aged about 26 years, around 1.73 m would have been provided with grave goods. Examination tall and of normal build; skeleton F, aged about 24 years, of the tomb drawings makes the situation quite clear, as around 1.75 m tall and of “particularly robust build”; and two distinct phases of deposition are present. Some pieces skeleton C, a boy aged about 11. The three females (skel- of furniture, presumably those interred with individual E, etons A, D and G) were aged approximately 15, 11 and 17 were already decaying when the later burials were made, respectively. as they were considerably disarranged. Other tables and One or more violent blows to the skull had killed all six stools, however, were found in the positions in which they individuals and they had been buried simultaneously some ultimately deteriorated, and it would make sense to asso- time after the interment of individual E. Males B, F and C ciate these items of furniture with the later burial of the were missing their right hands. Kenyon, interpreting this as six executed individuals. Such fine and expensive furni- evidence for a mass execution, suggested that the six were ture would hardly be appropriate grave goods for disgraced thieves caught robbing the tomb of individual E [3]. This tomb robbers. A further point of incongruity lies in the fact might, according to her, explain the “kicked about” condi- that three of the ‘tomb robbers’ (B, C and D) had been laid tion of skeleton E and the missing right hands of the three out on rush mats, in two instances with clearly associated males. She therefore proposed that males B, F and C were personal ornaments; again, improbably benevolent for the tomb robbers caught in the act, and that they and their burial of criminals. A much more plausible explanation for family had been executed and entombed. Kenyon’s explana- Tomb P19 is that the six simultaneously interred individuals tion seems highly improbable, as it is difficult to imagine a were killed in an enemy raid and, being of the same family situation in which apprehended criminals would be interred as individual E, were buried in the same tomb. The extensive in the very tomb they had desecrated. More significantly, and lavish nature of the grave goods, the majority of which her theory seems entirely contrary to the lavish nature of are clearly associated with these six, strongly indicates this. the burial offerings: pottery storage jars; bowls; vases; juglets The food remains found in the tomb, which included two and lamps; alabaster vessels; wooden tables, stools, platters complete lambs together with other joints of meat in bowls and boxes with delicately carved bone inlay; baskets; beads; and wooden platters, represent the remains of a burial feast scarabs; and a decorated ostrich eggshell. If Kenyon’s ‘tomb held in honour of the deceased. Although it is undeniable

112 THE MIDDLE BRONZE AGE FURNITURE FROM TOMB P19 AT JERICHO that the severing of the right hand was (and occasionally still is) a punishment for robbery in some areas of the Middle East, some ancient Egyptian peoples practised a similar mutilation in order to keep a tally of the dead. An illustration of this practice can be found in the scene depicted on the wall of the mortuary temple of Ramses III at Medinet Habu, in which Egyptian scribes are recording the numbers of severed hands recovered from enemy victims [8]. A puni- tive attack on Jericho could well account for the condition of the six individuals and their simultaneous interment in P19. The three executed girls A( , D and G) were buried with their right hands intact, suggesting that, as in the case of Egyptian tallying procedures, only ‘men’ or ‘warriors’ were counted. A re-examination of skeleton E prior to its inclusion in a reconstruction of part of P19 in the British Museum’s figure 2. A sketch from the unpublished Jericho archive showing how a wooden stool might have been constructed (redrawn by Antony Raymond and Beverly Sackler Gallery of the Ancient Levant Simpson) has added an additional interesting dimension. Preliminary analysis of this skeleton has revealed that the woman had a deformity of the left leg, sufficiently pronounced enough to have impaired mobility [9]. This observation helps to explain the presence of two wooden staves found beside skeleton E, interpreted by Kenyon as a “sign of rank” [3]. The two staves in question were found not just beside skeleton E but were quite clearly tucked beneath the left shoulder and, in this position and given the leg deformity, they should properly be interpreted as the constituent elements of a crutch. The new evidence makes it possible to state that the first interment in Tomb P19 in the Middle Bronze Age was of a disa- bled woman, aged about 28, who probably died of natural causes. She was buried not only with her crutch but also with a rich assemblage of grave goods, suggesting she was a person of high social status within Jericho society.

figure 3. Sketches from the unpublished Jericho archive showing the construction of wooden platters (redrawn by Antony Simpson)

IDENTIFYING THE WOODEN FURNITURE AND ARTEFACTS FROM TOMB P19

Understanding the problem In 2005 the first major study of the wood from the Bronze Age tombs at Jericho was published [10]. The long gap It is extremely fortunate that detailed drawings and photo- between excavation and identification is indicative that the graphic records were made after opening Tomb P19. They microscopic techniques available in the 1950s were insuf- remain the main source of information, along with the ficient to overcome the difficulties presented by the state of descriptive text [2, 5, 7], on the form, relative positions and preservation of the bulk of the material and reliable identi- condition of the grave items. They also provide the best fication was not possible. technological evidence for the construction of the wooden As detailed below, the principal consolidant used on the funerary furniture and artefacts, Figure 2. In theory, the Jericho wood around the time it was excavated was paraffin exceptional burial conditions of the Jericho wood suggest wax, which was liberally and extensively applied in situ. In that the assemblage should be an outstanding resource for most instances, the thick wax covered the wooden fragments the investigation of Bronze Age carpentry and wood use. to such an extent that carving, shaping, and any decorative Unfortunately, as soon as the tombs were opened, deterio- marks were obliterated. The high level of fragmentation, ration of the organic remains set in very quickly. Despite particularly of the large items of wooden funerary furniture the best efforts of the excavators, the conservation and such as tables and stools, was a major handicap to estab- lifting techniques available at the time were insufficiently lishing the precise and detailed relationship between arte- advanced to prevent further fragmentation of much of the fact type and wood identification [10]. Many fragments of rich assemblage, as the drawings of the time show, Figure 3. wood examined could not be attributed to a particular part

113 CAROLINE CARTWRIGHT, CLARE WARD, JONATHAN TUBB AND HÉLÈNE DELAUNAY of a piece of furniture, such as a table leg, or even specifi- number (3100) of fragments involved [10], and the method cally to a table. Meaningful quantitative estimates of the adopted in that study was that used for charcoal identifica- woods used for specific types of furniture or artefact in the tion, reflected light optical microscopy [15]. For the P19 Jericho funerary assemblage are not possible because of wood, SEM was vital, particularly using the variable pres- their highly fragmented state; counting fragments simply sure (VP) SEM. Both fractured and unfractured surfaces gives an index of fragmentation. were examined directly in the Hitachi S-3700N VP-SEM or Hitachi TM-1000 SEM. Using the VP-SEM significantly improved the preparation process for examination, Techniques of wood identification as it was not necessary to employ many of the sampling steps described in the previous study [10]. It is worth re- Standard techniques of wood identification and termi- emphasizing, however, that the number of features avail- nology as set out by the International Association of Wood able for characterization was still restricted because of the Anatomists (IAWA) are adopted for the identification of high shrinkage, distortion and impregnation by paraffin modern wood [11, 12]. For each sample, the key features wax, Figure 5. The extreme shrinkage of the wood was are compared with reference collection specimens and estimated by comparing it with inlaid bone ornamenta- textual descriptions [13, 14]. This methodology can often tion that retained its original form in composite artefacts. be applied to archaeological wood, providing it is modi- At least 25% shrinkage was present along the radial plane fied to accommodate the effects of the conditions of pres- and 16% along the axial, similar figures to those reported ervation, e.g. desiccation or charring. Each sample needs by Baker [16]. Despite all these obstacles, a surprisingly to be prepared to expose transverse, radial longitudinal diverse array of timbers could be reliably identified. and tangential longitudinal sections for identification. For modern and certain types of archaeological wood, thin sections of approximately 12–14 μm are cut on a micro- The wood identification of P19 furniture and artefacts: tome, mounted on glass microscope slides and examined results and discussion by transmitted light optical microscopy. Variants of these standard techniques were applied to the Jericho wood One of the main objectives of the 2005 study had been to fragments in an attempt to overcome the problems created establish whether particular woods had been used prefer- by the original conservation treatments. In order for wood entially for specific types of funerary furniture and small identification to be carried out successfully, sampling portable artefacts, such as platters, combs and juglets. The had to take place on an area that had been damaged and results showed that the Jericho funerary carpenters did not was free from wax, as this material penetrates and fills simply rely on whatever wood was most readily available the wood cells, preventing the recognition of diagnostic or common locally, irrespective of its particular proper- cellular characteristics. Heavy waxing typically penetrated ties, but that the main woods used were selected prin- up to 3 mm into the wood, seldom in a uniform manner, cipally because their properties matched carpentry and Figure 4. Scanning electron microscopy (SEM) was not design requirements. The Jericho carpenters clearly made practicable for the 2005 study, on account of the very large informed, careful and specific choices from the different

figure 4. Backscattered electron image of a tangential longitudinal figure 5. Backscattered electron image of a transverse surface of a section through a table fragment made from Cedrus libani (cedar of fragment from a wooden artefact from P19 made of Crataegus sp. Lebanon) wood, showing the soil present in the surface wax layer and (hawthorn), showing severely shrunken and distorted vessels, fibres the extent to which the wax has penetrated into the cellular structure. and parenchyma cells. Image: Hitachi S-3700N VP-SEM Image: Hitachi S-3700N VP-SEM

114 THE MIDDLE BRONZE AGE FURNITURE FROM TOMB P19 AT JERICHO vegetation types available locally, selecting for use prime libani (cedar of Lebanon). The timbers used for tables and timber from the Mediterranean vegetation, riverine gallery table components seem to fall into four groups. Group 1 forest or the wadi slopes. For very special artefacts, timber comprises ash and oak woods, ideal for the larger elements of was imported or cultivated locally [10]. tables. Group 2 contains woods that are soft, such as willow, Parr records that among the 57 identifiable items of light and fibrous, such as fig and tamarisk, or light but rela- wooden furniture documented from the Jericho tombs, tively tough, such as poplar (although poplar is not resistant there is a total of 28 tables [17]. Table 1 contains details of to insect attack). While care would be needed if these woods the P19 furniture and other artefacts and Figure 6 shows were used as load-bearing components, they could have the most intact table from P19, presumably three-legged been incorporated in other elements in the tables. Group to be stable on an uneven floor. The following woods have 3 includes woods used to make the finer features, such as been found in the manufacture of funerary tables, surviving the legs, which need to be suitable for carving or turning, either as intact items or recognizable fragments: Acacia sp. but also require strength and durability. Such qualities can (acacia); Ceratonia siliqua (carob); Ficus sp. (fig), Fraxinus be found in acacia, carob and hawthorn woods, although sp. (ash); Olea europaea (olive); Quercus sp. (oak); Salix sp. ash and oak are also sufficiently all-purpose to be used for (willow); and Tamarix sp. (tamarisk). Some of the smaller finer, as well as major, elements. Group 4 comprises those fragments were labelled by the excavators as belonging to woods that were most likely to have been used for elements the ‘tables’ category and their identifications are: Crataegus of decorative carving, inlay or veneer work on the tables. sp. (hawthorn); Populus sp. (poplar); Ziziphus spina-christi These include olive, Christ’s thorn, date palm and cedar of (Christ’s thorn); Phoenix dactylifera (date palm); and Cedrus Lebanon [10].

table 1.Wooden furniture and funerary artefacts from Jericho Tomb P19 in the British Museum Excavation No. British Museum No. Object details P19/U 1958,0211.48 (138869) Table fragments; two isolated fragments of border of table; tenons and bevelled edge; 28.0 and 24.8 cm P19/01 1958,0211.66 (138887) Nearly complete platter; four hooked lugs; low ring base; length (l) 34.8 cm × width (w) 22.8 cm P19/02 1958,0211.46 (138867) Table fragments forming the major part of the main board and three legs; 124.8 (l) × height (h) 42.0 cm P19/04 1958,0211.62 (138883) Roughly oval fragmentary platter; hooked lugs; rounded base; ridged rim; 30.0 (l) cm P19/05 1958,0211.65 (138886) Nearly complete platter; four hooked lugs; low ring base; 25.6 (l) × 16.8 (w) cm P19/06 1958,0211.52 (138873) Stool in many pieces; c.80.0 (l) × c.26.0 (h) cm P19/07 1958,0211.76 (138897) Staff; traces of a central longitudinal ridge; poorly preserved P19/08 1958,0211.75 (138896) Staff; traces of longitudinal ridge and grooves; broken, warped and decayed P19/13 1958,0211.74 (138895) Stick; tapering; fragmentary condition; circular section; plus a number of roughly rectangular pieces P19/15 1958,0211.60 (138881) Several lengths of slightly bevelled wooden strips P19/17 1958,0211.77 (138898) Toilet-box(es) fragments; 13 very thin and much warped pieces P19/18 1958,0211.67 (138888) Dipper juglet (upper half) with a recessed band with chevrons in relief above the junction; 66.0 (h) cm P19/19 1958,0211.81 (138902) Copper alloy knife found on table 2, beside joint of meat; curled tip; three rivets for handle; traces of wood; 22.0 (l) cm P19/20 1958,0211.47 (138868) Well-preserved table; fragments forming most of main board and three legs; 88.0 (l) × 44.0 (h) cm P19/20A 1958,0211.53 (138874) Stool fragments; poorly preserved P19/20B 1958,0211.59 (138880) Stool fragments; two stool feet; square section with bevelled edges, tapering to round peg foot P19/21A 1958,0211.56 (138877) Stool fragments; side rail with leg and shorter rail P19/21B 1958,0211.57 (138878) Stool leg; 18.4 (h) cm P19/21C 1958,0211.55 (138876) Four stool legs; 24.8 (h) cm P19/21D 1958,0211.58 (138879) Stool fragments; probably lower rails P19/21F 1958,0211.49 (138870) Table border fragment; bevelled edge; 42.4 (l) cm P19/21G 1958,0211.50 (138871) Table border fragment; bevelled edge; 32.8 (l) cm P19/21H 1958,0211.51 (138872) Table border fragment; bevelled edge; 22.4 (l) cm P19/46 1958,0211.70 (138891) Fragmentary comb; end bars and most of the teeth are missing, but preserved to full length; 5.4 (l) cm P19/47 1958,0211.71 (138892) Fragmentary comb; most teeth and upper bar missing; one side bar and a few teeth preserved to full width; 6.0 (l) cm P19/50 1958,0211.61 (138882) Many very decayed and twisted wooden strips P19/53 1958,0211.54 (138875) Stool fragments (53F is the leg fragment that may have been lathe-turned) P19/54 1958,0211.45 (138866) Table fragments; part of table top, one leg and the top of another P19/71 1958,0211.63 (138884) Platter; rounded base; bar handles with hooks at ends; ridged rim; 28.8 (l) × 24.0 (w) cm P19/71a 1958,0211.64 (138885) Platter; fragmentary and decayed; 25.6 (l) × 16.8 (w) cm P19/77 1958,0211.72 (138893) Comb; complete length of one side bar; two teeth remaining; teeth on both sides of central bar P19/78A 1958,0211.68 (138889) Comb; complete length; some teeth missing; 4.4 cm (l) P19/78B 1958,0211.69 (138890) Comb; complete length; some teeth missing; 4.7 cm (l) P19/88 1958,0211.73 (138894) Nail (dowel); polygonal in section

115 CAROLINE CARTWRIGHT, CLARE WARD, JONATHAN TUBB AND HÉLÈNE DELAUNAY

box, but high quality, imported timber (cedar of Lebanon) was also selected. Of note is the very fine technological use of Cedrus libani for the P19 boxes; the wood has been split down the radial plane to form thin sheets that could be bent or dowelled into place to create the boxes. One of these (No. 3), described as a wooden box in a basket from Tomb P19, was made from both Cedrus libani and Ziziphus spina-christi woods. Although another box from Tomb P19 (No. 17) was constructed mainly from thin sheets of Cedrus libani, it has a base of Prunus sp. wood. In many respects, figure 6. A relatively intact three-legged table from Tomb P19 this gives some clues to what must have been the elaborate use of different coloured and grained woods, veneers and bone inlays for the larger funerary items such as the In total, 27 stools have been recorded for the entire tables. Jericho funerary assemblage [17]. One type is a rectangular The staffs (or sticks), combs and juglet from P19 were bench-like construction with sturdy legs and paw-like feet. made from Olea europaea (olive) wood. Apart from its hard, The second type is square with narrow legs and plain feet. strong and dense properties that make it an ideal carving Both types had seats made from woven withies of willow, material, olive wood also has an attractive mottled figuring. tamarisk and Prunus sp. (plum/cherry/almond, etc.) [10]. It is seldom possible to obtain long lengths of olive wood Ricketts speculated whether a lathe could have been used timber. Carved wooden vessels found in the Jericho tombs [18], and a furniture leg fragment from P19 (number 53F) were illustrated and described by Kenyon as “platters”, made of carob wood shows regular incised lines that suggest “bowls” or even “dishes” and many had four handles carved lathe turning of some kind [10; Figure 5]. Other woods as ram’s heads or small lugs [2]; the P19 platters were made identified for stools were: Acacia sp., Crataegus sp., Populus of olive wood. sp., Prunus sp., Quercus sp., Salix sp. and Tamarix sp. The descriptions and drawings published by Kenyon The subdivision of use between legs, tops and decorative [2–4], and the suggested joinery techniques that were inlays dictated by the properties of acacia, willow, poplar and discussed and illustrated shortly after excavation [16, 18], tamarisk described above for the tables applies equally well provide tantalizing glimpses into the sophisticated joinery to stools and benches. In addition to providing soft, light but techniques, decorative carving, inlay work and veneering resistant wood, willow withies would also have been useful of this furniture. But in their current state, the heavy layer for furniture seats and basketry. Carob, acacia, hawthorn of discoloured paraffin wax obscures much of the evidence and various Prunus species such as almond or plum are best for such details. Before a further study of the technology of suited for the manufacture of furniture legs, not only on these objects could be undertaken, or indeed the furniture account of the dimensions of the branches frequently found made suitable for display, a technique to remove the disfig- on these trees, but also because these woods have common uring surface layer of wax without damaging the wood was properties of hardness, strength, density and durability. needed. Wooden veneers, inlays and strips were mostly attached to tables, but were also applied to stools, juglets and boxes. The main woods used were Crataegus sp., Olea europaea, Populus sp., Ziziphus spina-christi and Cedrus libani, with CONSERVATION ASSESSMENTS AND the last two used for dowels. The choice of Christ’s thorn TREATMENTS was ideal, as the wood is hard, very dense and durable. The selection of cedar of Lebanon wood for dowels was made Condition survey when other parts of the piece used the same wood, notably for the furniture inlay strips. Because of the current condi- During preparation for the new Levant galleries in 1998, tion of the P19 assemblage, it is not possible to specify in several organic objects from the excavations at Jericho detail the extent of wood veneering, i.e. the application of were examined to assess their condition and conservation thin slices or slips of wood onto a surface, compared to requirements. This gave an insight into the unique state of wood inlaying, in which thin segments of wood (often of preservation of this assemblage, but also underlined the a different colour) would be set into the surface layer of an fragile nature of these wooden artefacts and, as a result, a item of furniture. full conservation survey of the material was then carried Funerary boxes were made from Olea europaea, Prunus out [19]. Those fragments that had not been treated with sp., Punica granatum (pomegranate), Ziziphus spina-christi consolidants appeared to be in good condition with a natural and Cedrus libani woods. The ‘boxes’ category has yielded brown colour, while several combs seemed to have been particularly useful and new information about the use of treated with a dark, glossy, pigmented resin. The majority different types of wood on a single object. Not only were of the wooden objects had, however, been consolidated with several different types of wood used to make up a particular a thick wax that was identified as paraffin wax [20]. This

116 THE MIDDLE BRONZE AGE FURNITURE FROM TOMB P19 AT JERICHO had made the surface very dark, which gave the misleading after treatment they were very fragile; it proved impossible impression that the object, or at least the surface, had been to remove the paraffin wax completely without the object burnt. It seems that the application of paraffin wax was a disintegrating and any remaining paraffin wax impeded standard treatment for fragile objects from excavations in attempts to reconsolidate with other materials [23]. the Middle East from the 1920s to 1950s, particularly wood and bone. Woolley describes the application of boiling wax during excavations at Ur, where it was “ladled gener- Recent attempts at surface wax removal ously” over an object and the surrounding soil [21]. This wax coating has now darkened, giving the Jericho wood Although the dark coating of discoloured wax does not an unnatural appearance, and this has made it difficult to appear to be causing damage to the underlying wood, its examine the surface. As stated above, the penetration of the dark, glossy appearance disfigures the objects and, following wax is variable; on the pieces examined during the condition the reassessment of the material, it was felt that to enable survey it appeared to have penetrated to an average depth the carved and inlaid surfaces to be seen or examined more of 1–2 cm and, although somewhat unsightly, the smaller clearly, the wood needed to be cleaned to remove excess objects appeared to be stable. There were, however, some wax where possible. Three techniques were tested on small problems with the large structural pieces, which were solid unprovenanced fragments of Jericho tomb wood. The aim on the outside where the wood was impregnated with wax, was to remove sufficient wax from the surface so that the but had very soft, friable interiors where the wax had failed natural surface colour was revealed and any evidence of to penetrate. This difference had resulted in some breakages. technology could be examined, while leaving the surface of The survey recommended that many of the objects required the wood intact. While a non-contact method would clearly cleaning to remove dirt and old consolidants and that such be preferable, two of the techniques required some physical treatment should address the dark surface appearance and contact with the surface of the sample. reveal further evidence of surface detail [19], allowing a The first method tested was the use of solvents to remove more comprehensive study of the carpentry techniques. the wax. It was found that if industrial methylated spirit was applied to the surface, the layer of dirt and wax was softened and that this softened wax could be removed with Previous conservation treatments a scalpel. The latter step was difficult, since the underlying layer was highly irregular and great care had to be taken not Five very fragile wooden combs, which were covered with to remove the surface of the wood. The process was further a dark glossy consolidant that was found to be a resin complicated by the presence of pieces of loose wood and containing a brown pigment, had already been conserved soil in the surface layer of wax, Figures 4 and 7. for display. Acetone (propanone) had been applied on A second approach was to use a hot air tool (a pneumatic cotton wool buds to remove much of the surface resin power pen) to soften the wax, which was then absorbed and take down some very obvious old joins. As the wood while molten with tissue paper. A potentially beneficial side was heavily impregnated with the resin, it was judged that effect of this process was that excess molten wax flowed further removal would have resulted in damage to the into areas of weakness such as cracks. Although this offers wood. Nevertheless, after treatment, the wood became a additional support to the wood, the method leaves a thin, much more natural colour and surface detail was visible. As no new consolidant was introduced, the combs remained very fragile and were supported on a specially constructed recessed mount for storage and display [22]. As the condition survey revealed, the wax had only impregnated the outer layers of the wood and consequently did not completely consolidate it. In 1972 two methods that might remove the wax en masse were investigated, so that subsequent reconsolidation with another material could be attempted [23]. The first technique involved soaking representative samples of wax-impregnated wood in baths of toluene (methylbenzene) at room temperature; the solvent was changed daily. The second method involved the use of the so-called Soxhlet extraction technique; in a cyclical process hot solvent vapour condenses into a freely draining, permeable vessel containing the sample and the soluble material is extracted and carried into the reservoir of solvent that is being heated to provide the solvent vapour. figure 7. Backscattered electron image of a tangential longitudinal surface of a fragment from an artefact, showing loose pieces of wood, Neither technique was found to be particularly controllable detritus and soil present in the surface wax layer. Image: Hitachi and although the colour of the wood samples was lighter S-3700N VP-SEM

117 CAROLINE CARTWRIGHT, CLARE WARD, JONATHAN TUBB AND HÉLÈNE DELAUNAY if reduced, layer of wax on the surface of the wood and dirt of the pulse and resultant energy density (or fluence) are embedded in the wax will not be absorbed by the tissue controlled so that ablation occurs before the heat gain can paper and will remain on the surface of the object. be transferred from the layer to be removed to the under- The third technique employed in these tests was laser lying substrate. The fluence,usually measured in Joules per ablation of the wax layer. Since 2005 the British Museum has square centimetre (J.cm–2), must be high enough to remove been using a dual wavelength (532 and 1064 nm) Nd:YAG surface deposits but low enough to ensure that the surface laser to treat dirt- and pollution-encrusted stone sculptures of the object is not damaged [28]. and has been evaluating its potential for use on a variety of Experiments conducted on fragments of Jericho wood other types of materials [24, 25]. While laser cleaning has used both the 1064 and 532 nm lasers. The most promising been used successfully for many years as a method for the results were achieved using the green laser (532 nm) set to conservation of stone [26], its application to other substrates an output energy of 20 mJ, with a ceramic ring inserted into has yielded mixed results, although in the context of these the hand-piece to reduce the fluence by around 35% toc .1.33 tests on wood from Jericho it is worth noting that some J.cm–2. The laser beam caused the wax layer to become opaque success has been reported in the application of laser tech- and to delaminate from the underlying wood. Smaller frag- nology to the conservation of wood [27]. Research at the ments of wax were directly ejected during laser exposure, British Museum into the use of lasers has included trials in while the larger detached fragments became loose so that the conservation of organic materials and in the use of the they could be lifted away from the surface with forceps, laser in situations in which no other satisfactory cleaning Figure 8. An added advantage was that much of the exca- method is currently available; these research strands meet vation dirt and subsequent soiling had been incorporated in the case of the wood from Tomb P19. into the wax layer and was removed with it, giving a wood The properties of lasers and the theoretical basis for laser surface that appeared clean and undamaged, Figure 8d. The cleaning are covered elsewhere [26], but for the method surface was examined in more detail first using an optical employed in these trials the laser beam is directed onto the microscope and then at higher magnification in a variable surface of the object in short pulses through a pen-like hand- pressure scanning electron microscope (VP-SEM), Figure 9. piece within which a lens produces a diverging beam. The Although preliminary, these results with laser cleaning show laser energy is absorbed close to the surface, causing rapid some promise, and further studies will be conducted, not heating and expansion. If the expansion is sufficiently rapid, least to investigate the longer-term effects of laser cleaning the resultant forces eject matter from the surface. The length on wood.

figure 8. An unprovenanced sample of Jericho wood selected for laser treatment: (a) before treatment, showing the darkened wax layer on the surface; (b) after laser treatment of part of the fragment, showing a cleaned area near the centre and an opaque loose flake of wax to its right; (c) a detail at higher magnification showing the laser cleaned area to the lower left and an opaque wax flake at the centre; (d) the same detail with the wax flake turned over so that its underside, with embedded debris, is visible

118 THE MIDDLE BRONZE AGE FURNITURE FROM TOMB P19 AT JERICHO

Hélène Delaunay ([email protected]) are conservators, all in the Department of Conservation and Scientific Research. Jonathan Tubb ([email protected]) is a curator in the Department of the Middle East at the British Museum.

REFERENCES

1. Kenyon, K.M., ‘Excavations at Jericho’, Palestine Exploration Quarterly 86 (1954) 45–63. 2. Kenyon, K.M., Excavations at Jericho. I, British School of Archae- ology in Jerusalem, London (1960). 3. Kenyon, K.M., Excavations at Jericho. II. The tombs excavated in 1955–8, British School of Archaeology in Jerusalem, London (1965). 4. Kenyon, K.M., Archaeology of the Holy Land, British School of figure 9. An unprovenanced sample of Jericho wood, showing thick Archaeology in Jerusalem, London (1979). wax deposits to the lower left and the area cleaned by the laser to the 5. Kenyon, K.M., Excavations at Jericho. III, British School of Archae- upper right. Image: Hitachi TM-1000 SEM ology in Jerusalem, London (1981). 6. Kenyon, K.M. and Holland, T.A., Excavations at Jericho. IV, British School of Archaeology in Jerusalem, London (1982). 7. Kenyon, K.M. and Holland, T.A., Excavations at Jericho. V, British CONCLUSIONS School of Archaeology in Jerusalem, London (1983). 8. Nelson, H.H., Medinet Habu II: later historical records of Ramses III, University of Chicago, Chicago (1932) Plate 78. Kenyon’s excavations of Tomb P19 at Jericho revealed an 9. Stephany Leach, human osteologist, Tell es-Sa’idiyeh project, array of high quality wooden furniture and funerary arte- personal communication (1998). facts that provide an accurate reflection of the esteem 10. Cartwright, C.R., ‘The Bronze Age wooden tomb furniture from Jericho: the microscopical reconstruction of a distinctive placed on all the individuals buried within the tomb. carpentry tradition’, Palestine Exploration Quarterly 137 (2005) Although unusual conditions of desiccation preserved the 99–138. tomb’s organic materials, it is still proving difficult to gather 11. Wheeler, E.A., Pearson, R.G., LaPasha, C.A., Zack, T. and Hatley, W., Computer-aided wood identification, North Carolina Agricul- evidence of the sophisticated carpentry techniques from ture Research Service Bulletin 474, North Carolina (1986). the material as its present condition is adversely affected 12. Wheeler, E.A., Baas, P. and Gasson, P. (eds), ‘IAWA list of micro- by the thick coating of paraffin wax that was applied during scopic features for hardwood identification’, IAWA Bulletin 10 the excavations, masking surface detail and creating obsta- (1989) 219–332. 13. Fahn, A., Werker, E. and Baas, P., Wood anatomy and identifica- cles to wood identification. Recently introduced methods, tions of trees and shrubs from Israel and adjacent regions, Israel such as examination in the VP-SEM, have improved the Academy of Sciences, Jerusalem (1986). number of accurate wood identifications that are possible, 14. Schweingruber, F.H., Anatomy of European woods, Paul Haupt, increasing the number of different timbers characterized. Berne (1990). 15. Cartwright, C.R. and Parkington, J.E., ‘The wood charcoal assem- Recent condition assessments and new approaches to blages from Elands Bay Cave, southwestern Cape: principles, removing the wax coating from Tomb P19 wooden arte- procedures and preliminary interpretation’, South African Archae- facts and furniture, particularly the preliminary tests with ological Bulletin 52 (1997) 59–72. Furniture in the ancient world: origins and evolution the laser, have not only increased the possibility that new 16. Baker, H.S., 3100–475 bc, The Connoisseur, London (1966). technological information may be retrieved, but have also 17. Parr, P.J., ‘Middle Bronze Age furniture from Jericho and offered methods by which the appearance of this important Baghouz’, in The furniture of Western Asia: ancient and traditional, material may be significantly improved, allowing it to be ed. G. Herrmann, Philipp von Zabern, Mainz (1996) 41–48. displayed to the public to its best advantage. 18. Ricketts, M., ‘Furniture from the Middle Bronze Age tombs’, in Excavations at Jericho. I, ed. K.M. Kenyon, British School of Archaeology in Jerusalem, London (1960) 527–533. 19. Ward, C., ‘Conservation survey of the organic artefacts in the Jericho Collection, Department of the Ancient Near East’, Depart- ment of Conservation Report No. 2001/1/0/1, ACKNOWLEDGEMENTS British Museum (2001) (unpublished). 20. Fields, J., ‘Analysis of surface materials from the Jericho collec- The authors would like to thank Antony Simpson, Monique Pullan, tion’, Conservation Research Group Report No. CA2000/35, British David Singleton, Claire Robinson, Sophie Rowe and John Fields. Museum (2000) (unpublished). 21. Woolley, L., Digging up the past, Penguin Books, Harmondsworth (1930) 116. 22. Pullen, M. and Ward, C., ‘A mounting system for fragile wooden combs: an interdisciplinary approach’, Conservation News 70 AUTHORS (1999) 7–18. 23. Blackshaw, S., ‘Attempts to strengthen wood from a tomb at Caroline Cartwright ([email protected]) is a Jericho’, Conservation Research Group Report No. 3237, British scientist, and Clare Ward ([email protected]) and Museum (1972) (unpublished).

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24. Korenberg, C. and Baldwin, A., ‘Laser cleaning tests on archae- 26. Cooper, M. (ed.), Laser cleaning in conservation: an introduction, ological copper alloy using an Nd:YAG laser’, Laser Chemistry Butterworth-Heinemann, Oxford (1998). (2006) Article 75831. 27. Cooper, M., Solajic, M., Usher G. and Ostapkowicz, J., ‘The 25. Korenberg, C., Baldwin, A.M. and Pouli, P., ‘Investigating and application of laser technology to the conservation of a Haida optimising the laser cleaning of corroded iron’, in Lasers in the totem pole’, Journal of Cultural Heritage 4 (2003) 165–173. conservation of artworks: Proceedings of the International Confer- 28. Cooper, M., ‘Recent developments in laser cleaning’, The Building ence Lacona VII, ed. M. Castillejo, P. Moreno, M. Oujja, R. Radvan Conservation Directory (1997): www.buildingconservation.com/ and J. Ruiz, CRC Press, London (2008) 291–296. articles/laser/laser.htm (accessed 10 May 2009).

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