Scientific In,, t~ ument Society

Bulletin March No. 72 2002 Bulletin of the Scientific Instrument Society ISSN0956-8271

For Table of Contents, see back cover

President Gerard Tum~

Vice-President Howard Dawes

Honorary Committee Gloria Clifton,Chairman Ron Bristow, Secreta~ Simon Cl~ifetz, Treasurer Willem Hackmann, Editor Peter de Clercq, Meetings Secretary Alexander Crum Ewing Tom Lamb Tom Newth Alan Stimpson Sylvia Sumira Trevor Waterman

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jr - JY" "it ! - issue's Mystery Object. It is a model 0 proposed by the German botnist Carl lgnatz Leopold Kny (1841-1916). Knv was profes- sor of Plant Physiology at the ~ndw/rtschaf- tliche Hoch~hule in Berlin who studied the development and growth of plants. Paolo writes that he is not a ~tanist and there(ore his explanation will be quite approximate. The lines on the glass tube of the mystery instrument are just a representation of the so-called 'genetic spirals' (spiralegi, n~atri- ce). From a purely morphological point of view the various parts of a plant (leaves, petal, aem etc) are regarded as 'mem- bers. Members growing at the same level on a common axis (called 'whorl') are represented with a section diagram as shown in Fig. I. If we imagine a spiral starting from a member and passing trough Fxe. l$...-:.Diagrxm ofmul- all the intersectionsmembers situated above it (for examples the leaves on a stem) and tilsteral m~stered xrr~Ke- following their development we have a merit, with dlvergenoe of t. genetic spiral (Fig. 2). This spiral is the line engravedon the mystery ob~. The other r IPm, "|L~D~ ~ mm [usa. t~. ~,ama ~oe lines and the fraction 2/5 indicate a Fig.l Section diagram of morphological mem- |wbloh I~vo t~o ooRamm~~lll- particular kind of symmetry present in |m o¢|, *moNee *me bers taken from Vines textbook. /,,,mm~-t~. =m-h~= m ~s4t- various plant. Paolo suggests that if more bT ~ ZaNiest, details are required, to consult: Julius Sachs, ch,~s Wl ~ ~ b3" Lehrbuch der Botanik (Leipzig, 1873), pp. 174- Broken Bones 187, and Sydney H. Vines. A Students" Te~- It is very gratifying that interesting papers Book of Botany (New York, 1910), pp. 23-31. continue to be submitted to the Bulletin from all parts of the globe. From that viewpoint Fig.2 Genetic spirals taken Brendel in Berlin was a maker who both the Bulletin and instrumental history is from Vines textbook. Sof~oCwialized m botanical models (plants, thriving. On the negative side membership er, etc.), in the collection of the to the Society has been dropping slightly Fondazione Scienza e Tecnica of Florence recently. This may be due to the recession or merits. For more information contact: De- (as well as in many other didactic collec- to the increasing power of the intemet borah Jean Warner, Curator, Physical tions!) dozen of Bmrgid models survive. catering for specialist interests. The SIS, as Sciences Collection, National Museum of the title denotes, covers the entire spectrum American History, 0636, Washington, of instrumental history, which has its D.C. 20013-7012. Also Bill Burns (e-mail: strengths and weaknesses. The 'mix' of mailto:[email protected]) has added a papers that are published in each issue of page on the Orleans, Massachusetts, cable the Bulletin is dependent on what has been station museum to his Atlantic Cable Cover Story submitted and on the space available. The website: http://atlantic-cable.corn/ Arti- Editor tries to vary the fare from issue to cle/FrenchCableStation. This cable station issue as much ashe can in the hope that was built in 1891 and operated until 1959. Willem Hackmann every reader will find at least something of The page includes a number of photograpkq ~iaI interest. This is a tall order but the of interestingoriginal equipment. Editor believes passionately in the need for a To end on a personal note, to get this Bulletin wide-ranging interdisciplinary }oumal in This iasue's cover illustration is to celebrate ready for publication has been a painful Professor Michael Cooper's wide-ranging the field of scientific instruments. What do experience as at the end of January I badly you think? Ninth Annual Invitation lecture on the broke my left leg in a fall resulting in a history of land and hydrographic surveying, Congratulations to Paoio Brenni for having compound fracture which has destroyed in particular the evolution from opto- been awarded the 2002 Paul Bunge Prize in much soft tissue in the ankle. Most of this mechanical surveying instruments to the recognition for his works in the field of the issue has been edited in a haze of painkillers electronic surveying systems of today. The history of scientificinstrument and material on a laptop perched precariously over my illustration is the title page of Aaron culture. The Geselleschaft Deutscher Che- temporary bed made up in the living Rathbome's The Surt~Cor in Four B~,es, micher will award the prize on the 10~ of downstairs to which [ have been restricted. published in 1616. Rathborne (1572-1618) The surgeons predict that ! shall be fully May at the University of Potsdam during was probably a Yorkshire man who moved the opening session of the 'Bunsen-Tagung'. mobile again m five months, so I crave to London as an engraver and pm/essional This is a well-deserved honour. indulgence for all those unanswered e-mails surveyor. He may have been an apprentice of and any additional errors that may have John C,odwyn and was a member of the Anne C. van Heiden has resigned from crept into this issue. London circle of mathematical practitioners Museum Boerhaave after fourteen years in Corrisenda which included Henry Briggs, the first post to take up a position as physics teacher Gresham Professor of Geometry in London in a secondary school. We wish him every Minor errors occum.d in two of the captions and the first Professor of ~metry at success and regret the loss of his experience of the figures accompanying the paper on Oxford, and John Speidell, a professional to our sui~ect, in particular on the history of the restoration of instruments of the teacher of mathematics and friend of Elias the air pump. Palermo Observatory in the December Allen. In his book Rathborne recommended Deborah Warner has drawn our attention to issue. In Fig. I the columns support the the use of printed pocket-tables of k~ga- a new on-line catalogue at http://american- verticaland not the horizontal circle,and m rithms, sines, tangents and secants. Gerard history.si.edu/surveying, of surveying and Fig. 9 the word 'scale'should be deleted in Turner in his Eli~brthan Instrument Makers geodetic instruments in the National Mu- the third line. (OUR 2000), illustrates(item 76) a surveyor's seum of American History. This is a work in Mys~ry Object Solved a~OKr, which he tentatively attributes to progress: more images are to come, as well ynvyd and ~y resembles an as descriptions of about 50 more insla'u- Paolo Brenni has solved the December engraving in Rathbome's book.

Bulletin of the Sc~tific ~t Society No. 72 (2002) 1 The Annual Invitation Lecture From Graduations on Metal to Binary Biphase Modulation, or From Land and Hydrographic Surveying to Geomatics Michael Cooper, Fro, Professorof Engineering Surveying School of Engine,".' .ity University London

ca |... . A Historical Context The era of prehistoric surveying began about 50,000 years before the present (BP), I~ssibly earlier, when hunter-gath- erers roamed the land. If surveying is a means of acquiring information and knowledge about the earth and its resources, knowing how to find a way from one place to another, and passing on all that information, then homo ~piens was a surveyor from the earliest times. For each one of these ancient people, surveying was literally a matter of life or death. In order to survive, everyone had to know where to find fia~ and water (even when n(me could be seen) how to move from place to place, and when to do ~,. Locations in time and space were not measured by instrumen~ but reck- g~g.l I',,rt,~l./, C,m~cra ob-,.~,: ,tt'c~tc t,v oned bv the senses and embedded in "~,q';'m.~,'. From W. Derh,mt. ed, R~ert song and myth for the benefit of present th~&e's l'hih~phical Experiments and and future g'enerations. Surveying instru- Ob,,ervations ~l.~mdon, 1720~. ments came into use to impnwe our sen.,~es and memory, in order to meet I ntrod uction increasingly complex social needs. I am honoured to have been invited to The ancient era of surveying started gl~e the ~lentific Instrument Society's around 7,t~)BP when pt~ple began to Fig.2 11.' tittl: and last ot the '(.,rent Annual Lecture. Its sub-title implies tl~at live in ~ttlements. The earliest material Theodolites' commissioned .fn;m Troughton change~ in land and hydrographic sur- evidence of surveying as a specialised & Simms in 1857 tbr tr(~,on,,metrical surz~ ~,e!,lng instruments have transformed activity comes from MesoFn~tamia and ,~. lndhr Completed in 1867, but nawr u~cl. practice to such an extent that the noun Ancient Egypt where surveyors worked Now m South Africa. J.R. Smith. ' ~'eomatlcs" has come into use for the new in the flta~-plains of the Tigris, Euphrates practice [ do not intend to anah,'ze the and Nile rivers, irrigating , measuring, The gradual rejectionof Ptolemy's system cttt'cts of global economic, i~ditical and recording and valuing agricultural land? of the world and acceptance of the tcchnological changt.~ on land and hv- They al.,~ worked on monuments built to Copernican heliocentricuniverse was an dn~raphic ~,un.eyin G in the last 50 veal. the glory of deities and earthh: rulers, indirect cau~ of the beginning of the In-toad I ,,hall d~.,cribe .'~me personal ensuring that the structures were erected modern era of surveying around l.¢4kqAD. cx[.~.'rlenct~and offer opinions of ~)me and aligned properly to mark iml~rtant The particular catalyst of instrumental land ,urveyln G instruments I have used celestial events. An understanding of change was Galileo'suse of glags lenses in a, a~ademic and practitioner through five geomet D' and the u~, of mechanical his teh.'scopefor .scientificinvestigations decadt% of change. I realize that in doing devices such as knotted ropes, rectangular (Fig. I)? It ~ surveying technology on a this [ am departin G mmwwhat from the sighting frames, plumb-lines and gradu- course that lasted for nearly ~0 years high standards of ~holarship .set bv atecl circular or ~'ctorial arcs made from (Fig. 2)." Theodolites, levels, tache- previou,, annual lecturers. But when fibres, w,nM and metal characterized ometers, sextants, photogrammetric cam- readin G academic accounts of historical ancient surveying until the sixteenth eras and stereop[ottersevolved as opto- -urxeyin G 1 have sometimes noticed that century. 1 suggest that Heron of Alexan- mechanical materials and industrialman- firq-hand evidence from contem~warv dria would have underskn~ the general ufacturing techniques developed. But the u,.ers and makers of instruments was purpose and use of Wald~emfiller's m(~ern era came to an end around 1950 mt~in G, but might have been interesting, Polimetrum as readih,, as the latter would AD when technological changes began and pt~slbiy u~,ful to historians, even if have undershaM Ht'ron's Dioptra.: Of whtz~e effects on surveying have been it s~ere as random and partial as my own course the accuracy of instruments in this much more rapid and wide-ranging than t'~ ldence this evening. era improved, the u.,~es to which they were anything that went before. put became more varied and their I ~hall start b.v placing the last ~} ','ears of ornamentation more highly valued as •,urxeying in a longer tem[~wal [~erspec- Although electricalcoml~ments had been civilisations became ~phisticated.' Sur- mcorl~rated in surveying equipment for ti~e by identifying four main eras of veying calculations, algebra and algo- sur~,e.virl G, diffen.ntiated farm one an- ~veral decades, the advent of electronics rithms were devi~,d in Islam, but for in the 19~)s, particularly the transistor other bv changes in technology. [ shall m¢~t .'~ci,~,conomic purposes in the west then go on to di~-uss and illustrate and later, integrated circuits, brought surveying was largely a mechanical about the most recent transformation of ~arious instruments and how they were activity, pn~lucing graphical or pictorial u~,fl befon, concluding and raising one surveying instrumentation. Th¢~se of us results which ~rved a variety of .~w,ial, who have been surveyors since the 1950s or two qut~,tions. religious and final purl~.~es. have been the victims (or beneficiaries)of"

Bulletin of the ~k'ntific Instrument S~iety No. 72 (2002) accurately as practicable a primary (or scientific, gendetic) control framework covenng the country using field astron- omy, base-line measurements with invar tapes in catenary, triangulation or traver- sing and precise levelling. Latitudes and longitt,des of primary trig. stations and heights of fundamental bench marks between 20 and 60 miles apart were computed from measurvments. Then the accuracy of measurements and computa- tions were lowered successively to give increasingly dense distributi(m of survey stations and bench marks until they were close enough to be convenient as the basis of surveying for detailed contoured maps and plans, setting out ctmstruction works and registrationof land parcels.Of course it was not possible to spend the decades that were necessary to finish the primary control before starting second- ary and tertiary surveying, so all activ- ities had to take place simultaneously. One of the main tasks in colonial Fig.3 G~,e, Troughton & Simms 5-inch mapping was to set priorities in the use hori~mtal circle Ge~detic Trn,istock Theodo- of inadequate resources. lite, in G. Bomford, Geodesy (Ox.~rd, 1952). Theodolites Fig.4 Wild ?'210 theodolite. Manu.fac- turer~ publication. more changes in surveying technology, We were taught standard manual proce- equipment and pn~cedures than took dunes for observing, recording the mea- place in the preceding 7000 years. As surements ('lx~king') and computing. British thetcloliteused for tertiary work my ~nly concessi~m to the m~Kles of the Opto-mechanical theodolites were used such as traversing and tacheometry for current burgeoning area of academic for the primary triangulation t~erva- large scale plans and setting-out was the cultural studies ! shall call the present tions. The C~ke Troughton and Simms Watts vernier theodolite which could era the post-modern era of surveying. ~ (later Vickers) Geodetic Tavistock theo- easily be kept in adjustment if the tools Automation Ls now widespread in ac- dolite was common in the British had not been removed by mischief or quiring, analysing and presenting spatial Colonies (Fig. 3).: Its optical micrometers carelessness as they lay invitingly in their w~xlden data and associated informati¢m. Artifi- were read through rotatable microscopes a~igned places in the opened cial earth satellitesystems provide digital which were vulnerable to damage in the box, ~ images of high fidelity and great diver- sometimes hazardous life of trekking with head-loads through narrow paths Overcoming patriotism for the sake of sity, whereas others rapidly generate and efficiency, ! never took a CT&-S theodolite transmit kinematic [:x;sitioning data of over rough ground. The micrometers were set by equalizing two 'light gaps' from the store if the corres~mding Wild high accuracy and increasing reliability. the~lolite were available. I used different A surveyor from even the latter years of which required regular adjustment to an acceptable width. The alternative to the versions of the Wild "1"2 for decades and the late modern era would be bewildered always found them stable and reliable.'" by the technology and askmished at the Ge~letic 'Tavi' for primary triangulation was the Swiss Wild "1"3. The Geodetic Like the Vollcswagen Beetle they have speed and accuracy of surveying in the 'Tavi' horizontal circle readings could be gone through many small improvements post-modern era. But she would recog- made directly to 0.5" (arc seconds) the T3 in design and manufacture over many nize that military requirements continue years, each successive change hardly to influence the course of major techno- to 0.2", but comparison of their weights reveals a significant difference. The T3 m~ticeable in itself (Fig. 4)." The dis- logical change. A notable feature of the weighed 1.4kg more than the Ge~letic tinctive features of the CI"&S Tavistock three pre-~st-mt~ern eras is their ex- 'Tavi', but its carrying ca~ weighed might make it more appealing than the ponential rate of decrease in duration. If 2.Okg less; the strength of the T3 was in Wild T2 to a collector, but i suspect m(~t it continues we have only ten years of the instrument where it should be, not in practitkmers would ch~e the latter. The post-modern surveying ]eft - hardly its carrying ca~. Such distinctions were CT&S instruments It~k as if they were enough time to get used to using the irrelevant however when a ge~letic designed by a committee, whk'h the*,' word 'geomatics'. theodolite was accidentally' destroyed were, in Tavistock, Devon in 1926 when by a spark from the camp fire setting British instrument makers and military' My personal experience covers the end of the store tent alight, or dropped from a surveyors decided what a theodolite the modern era and the beginning of the 60ft Bilby tower. Surveyors' written should be. I~st-m(~.tern. in 1950 Britain had many" reports to HQ on such malicious acts of colonies for which maps were urgently fate ranged hx~m the subtly tedious to the The Swiss surveyor i-leinrich Wild (187% needed. The Colonial Office recruited wildly exciting. 1951) was a remarkable man.'" When annually up to 15 graduates in Geogra- sun'eying in high Alpine regions he phy, Mathematics or Physics and .sent us The CT&S Tavistock was the second- became dissatisfied with mechanical to the School of Military Survey, Royal order instrument, reading directly to 1". thet~olites and their exp~"~-,d .scales and Engineers for a year to ]earn topographi- It was used for many kinds of surveying. bubbles, externally focussing telescopes cal surveying. We were taught the A surveyor would expect to have a 1" and diametrically opl~r~*d verniers or principle of working 'from the whole to theodolite allocated permanently micn~meters which necessitated mo~ mg the part' that is to establish first as throughout a tour of duty. ~ A common around the the~lolite in order to read

Bulletin of the Sc~tific instrumc~t S~iety No. 72 (L~102) ~ P'~lill~ qP.dd

Fig.6 Kern DKRV zwrtical staff tache- ~IF~ T4 ,,meter. Fn,m R.I. Smith, Optical Distance Measurement, Chmdon: Crosbu iaw~l~d, Fig.7 Wiht RDH. Manufacturer's publica- Fig.5 Wild T4 astronomical theodohte. 1970}. tion. Mamdacturer's publication. them. He had an idea to brmg diame- incorporated in the Hilger & Watts cantly higher than stadia theodolite trically opposed sectors of a circle into Microptic No.l and No.2 theodolites. tacheometry and the booking and plot- view through an optical train so that the,,' His DKMl is remarkable for its small ting were still manual. The only advan- could both be read simultaneously from size, but requires delicate hands to get tage was avoiding use of tacheometric a microscope adjacent to the telescope. the most out of it. Heinrich Wild died tables. A dimdvantage was the rather He found no company in Switzerland alm~st exactly 50 years ago, on Christ- awkward support neces.,mry for the staff. that could make what he had in mind, so mas Eve 1951. ! would like to acknowl- in 19(k~ he went to Zeiss in Germany to edge his great contribution to practical Optical-mechanical double-image tache- put his ideas into practice. As their chief land surveying. ometers using horizontal staffs were designer of geodetic instruments he used made for a few years. Generally more cylindrical primary axes in place of Opto-mechanical Tacheometers accurate than vertical staff tacheometry conical, coincidence viewing of bubbles, Conventional fixed-stadia tacheometry they were used not so much for detail and internally-focussing, sealed, anailac- with a theodolite such as the Watts surveys, but for tertiary traverses over tic tele~opes. The First World War vernier shown earlier, and a common terrain where ground taping or chaining interrupted Zeiss's innovative design levelling staff, was used to survey the would be difficult. The Wild RDH is a and manufacturing programme, but in plan [xvsitions and heights of points of typical example of a well-engineered 1920 work began on the first opto- detail and spot heights for large scale instrument (Fig. 7)'; The principle of mechanical theodolite and in 1922 Zeiss maps and plans. We used Redmond's double-image tacheometers is that one started production of the Zeiss Thl. By Tacheometric Tables to find horizontal image of the staff is formed normally by 1921 however, frustrated by Zeiss's distances and height differences from the telescope, but another, formed by rays slowness in putting his ideas into staff readings of stadia and level hairs. which pass through an optical wedge, is production, Wild had returned to Swit- The detail l~ints were plotted manually displaced laterally relative to the normal zerland and set up a company that and ioined-up or interpolated to show became famous throughout the world image.The amount of displacement is features and contours. Diagram tache- related to the wedge angle, the distance as Wild Heerbrugg Ltd. '~ The Wild 1"2 ometers were devised by most instru- between the image plane and the wedge, was produced in 1923, followed by the ment makers to give horizontal distances T3 in 1925 and the pinnacle of opto- and the distance of the staff from the and height differences directly and so tacheometer. The optics are so arranged mechanical theodolites, the 1"4 astronom- remove the need to use tacheometric ical thetu:lolite in 1940 (Fig. 5)? ~ that an observer sees in the telescope the tables. The Kern DK-RV (Fig. 6)" in normal and the displaced images adjacent addition to a conventional graticule with to one another and can read the position Heinrich Wild had many innovative fixed cross-hairs also carried a glass of one relative to the other (with the aid of ideas, but lacked the patience necessary diagram of engraved lines) ~ As the a micrometer for fine reading) which is to ~,e them through to production, so he telescope was elevated or depressecl from directly related to the horizontal distance left Wild Heerbrugg and set up as a the horizontal, the diagram, by means of from tacheometer to staff. TM The vertical consultant rolling patents to manufac- a gear train, was rotated in such a way circle is graduated not in angular units, turers of theodolites in Switzerland, that the intercepts of the diagram lines but in tangents so that height differenc~ notably the Swiss firm Kern Aarau with the staff were always directly between tacheometer and staff are ob- (which" u.secl his ideas in their DKM series related to the horizontal distance and tained simply by multiplication. Inge- of theodolites and tripods in 1937) height difference from the centre of the nious designs, fine opto-mechanical Germany (East and West) and Great tacheometer to the staff. The accuracy of engineering and relative scarcity of dia- Britain where in 1947 his designs were diagram tacheometry was not signifi- gram and double image tacheometers in

4 Bulletin of the Scientific Instrument Society No. 72 (2(102) Fig.8 Zeiss ~( )l~erk~'ln'n~ Ni2 .~'ction. Mmn!~i~ctun.rs t,ublicatinn. Fig.9 Zeiss Clena; Ni~M~2 geodetic ie~'l. Fn,m MAR. Ga,Fa'r, Modem Theodolites & Levels, 2nd edition (Lond, m: Granada. 1982).

my view make them more interesting without losing accuracy. Preci~ levels A mirror compen.~tor suspended at half than the contemporary theodolites, but a were fitted with a parallel-plate micro- the h~cal distance from the objective collector should recognize that the staff meter mounted in ~mt of the objective reflects the image onto the reticule, and support are essential comp~ments so that the line of sight, when horizontal, focussing being achieved by longitudinal without which the tacheometer's inge- could be raLsed or lowered to intersect translati~m of the compensator. Inciden- nious design and accuracy can not be the invar staff at a graduation, thus tally, the Zeiss (Jena) Company assigned properly demonstrated. obviating the need to inter~)late between model numbers to its levels to indicate graduations by eye.:" Verticality and their precision: the NiiX)2 is capable of Levels stability of staffs were provided by giving a precision of ±0.2ram per km of plumb-b(~s, ground plates and support double levelling (i.e. the average of 1he main function of a level is to provide struts. No ge~:letic levelling could be outward and return levelling); the NiO07 a horizontal line of sight, so levels are satisfactorily undertaken without follow- is capable of ±0.7mm; and the Ni05(1 of much simpler than theodolites and ing strict procedures in the u~ and care ±5ram, etc. The accuracy and speed of tacheometers and perhaps less attractive of the staffs as well as the instrument. precise levelling with the Ni00"2 has been to collectors. Nevertheless, significant Staff-holding was even more boring than demonstrated for many years, particu- changes have taken place in their design taking and recording the readings.:' larly in Sweden where the level and staffs and construction since 1950 and ! would are carried in convoy on small vehich.,s, like to say something about a few Most levels now contain a compen~tor stopping only briefly to lower the tript~ls particular instruments. The Watts so- which optically rectifies small deviationLs to the ground at pr~marked i~itions for called 'self-adjusting' level was a parti- of the line of collimation in the tele~L'ope taking, logging and checking readings. cularly robust general-purpose tilting from the horizontal. Compen~tors are The rotatable eyepiece of the NiIX)2 level on construction sites at home and usually suspended optical trains, hanging allows the sun,'eyor to take I~th back overseas, used for all but the highest freely under gravity, but damped to stop and fore sights from a seat in the rear of accuracy levelling. TM The other British (~scillations.The Zeiss (Oberkochen) Ni2 the vehicle and enter the readings level of note I'd like to mention is the was an early and widely u.,~sJ example of directly into a computer. Cooke, Troughton and Simms $500 a compen~tor level. Although the prin- preci~ (or geodetic) level. Geodetic ciple of coml~'nsation can be simply levelling had to be as accurate as illustrated its realization has to be quite it will not surpnse to you to hear that staff practicable in order to establish the ingenious in levels of the size and qualib/, readings can now be made automatically, heights of national fundamental bench of the Zeiss instruments (Fig. 8)/: as in the Leica coml~,n.~ltor digital levels. marks relative to a Mean ,Sea Level A digital image of the portion of bar code datum. Lines of k,vels ran for hundreds I would like to show you now a preci~ in the field of view of the tek~cope is of miles, mainly along roads and rail- compen~tor level which has an unusual matched with the cl~.|e of the whole staff ways, to form a network of ha~ps, each of design and is an example of fine stored m memory' to locate the intersec- which had to 'close' to within small engineenng. It could become, at least in tion of the line ~f collimation with the tolerances. It was not practicable to wait its original form, a rare item for staff. The surveyor can instruct the many months, or even a year or two, collectors, although as with diagram micropn~'es.,~w to make repeated staff until one of the ka~ps had bten com- and double-image tacheometers, a pre- readings until the mean has a specified pleted before seeing whether or not the cise level without its staff is incomplete. precision. All readings and auxilian" data levelling met the specificati¢~n (it alm(~st Made by Zeiss (Jena) before German can be stored in a memon' module and certainly would not) gl many strict unification, it was derived fn~m an earlier downk~idtxl to a laptop when necessa~'. regulati(ms governing the pn)cedurefi instrument, the NiA31, made by the Conversely, tor engineering purp¢~"s, for geodetic levelling were devised. Hungarian company MOM I have some setting-out data can be loaded into the Checks against errors were made con- recollection of a visit to the Leipzig memory module and called up on .,,ite. tinuously and unvaryingly. Geodetic Spring Fair around 1975 where I .saw a The preci~ NA3IXX1 ~ries can give levelling was then the most boring prototype of the MOM instrument and standard deviations of about ±lmm ~,r occupation for a field surveyor, allowing met its designer Paul Toth. In the Zei.~ km of double levelling, if invar statfs are no scope for imaginative methods or Ni002 (Fig. 9),:' the reticule, engraved on used in adequate lighting and free from procedures for covering terrain quickly a prism, is cemented to the ob~'tive lens. moving shadows.

Bulletin of the Scientific Instrument S~iety No. 72 (2iX)2) FOr lilt lind econom.c d ~1 .r.(-~. de,.tmm|I(o~ AGA GEODIMETER MODEL "6"

AGA tOolt a 10gI~HN~ aid m • ~at, ut~og I•lle

AGA GEODIMETERS Fig.ll HP.3820A lbtal .",tat,,t', in MAR G~,per, Modem The~iolites & Levels, 211,t e,tttwn tLontf,,n: Gnlnada, 1982L Fig.lO AGA Gei~iimeter O 1904. Adzvr- tlsement itt Surveu Rc'z'iew. 18-140 tApril Fig.12 Sokkisha On,a, So~klaJ StT2 "Tota 19ot,~. robust and more automated, displaying Station', c. 1985, 2"' angles, +/- (3ram + the measured distance after only a few 2ppmL Primal. axis tilt correction, 2kin range in avera,c,e condithms, I prism, 3.4kin Electronic Tacheometers .,~conds of measurement. Carrier fie- quencies corresponding to 0.gpm in the ditto, 9 prisms, 7.okf u,ith batte~, no case. The post-modem era of surveying began near infra-red became the norm Manu~wturer's publicathm. when instruments for electromagnetic Electr~ptical EDM was combined with distance measurement (EDM) using visi- a theodolite in two different ways. The ble light or near-infra-wd carrier wave- electro-optical devices to pn~duce digital simplest and cheapest was to mount an lengths came into u..~ in the 19~s and data. :~ (hae of the first ci~led the~olitt,,s EDM device on a conventional opto- l~k. The continuous signal transmitted was made by Fennel in 1968 which mechanical theodolite, but this was a from the instrument was reflecttM by a recorded circle readings on 35ram film. compromise. :~ In 197q AGA started corner-cu~, prism at the tar end of "the The l~70s ,saw a burgeoning develop- prl~tuction of the Geodimeter 100 .series hne to be measured, or rather from a wall ment of electronic tacheometers using which measured distances up to about of such prisms in the early days, back to infra-red carrier signals• These instru- 2kin in daylight with an accuracy of the instrument ~here tile transit time ments became increasingly automated, about _+(Smm + 5ppm) where 'ppm' is was d~xtuced fn~m measurements of the taking away from the surveyor the nt~t parts per million (or mm per kin) of the phase differences between the outgoing to perform repetitive manual tasks. One measured distance. The,,~, figures are and incoming sinusoidal m~lulations of of the earliest electronic tacheometers characteristic of many similar add-on the amplitude of the carrier signal. A was Hewlett Packard's HP,'~820A, intro- electr~ptical EDM units at that time. prototype (.;eodimeter made by the duced in 1977 with g(~i electronics but Perched on top of a theodolite designed _qwedish Company AGA was built as less gin~l optics, including a Cassegrain to bear quite different h~ads they were earh' as 1947, but early production telescope (Fig. ll).': Hewlett Packard not easy to u~'. Even operating the EDM mt~.iels were heavv and unsuitable as named the instrument 'Total Station', switches would ,,~mletimes cause the livid surveying instruments. ]he first to an utterly meaningless and highly theodolite to move in its clamps. Power be ~delv u.~xt was the (.k'~Mimeter successful phrase which in the English- cabk~ dragging on the th¢~dolite were a ,~'r~es, the first model of which was nuisance, ,,~)metimt.'s a hazard. The EDM speaking world has ~'come generic of produced in 19o4 (Fig.lO). :~ It was optics wot, ld hn) easily bocome misa- all electronic tacheometers. Japanese notable for having coaxial optics for lign~t with the the~|olite telLs,cope axis manufacturers were active in manufac- tran~,nutting and rtx-eiving, lightweight ~ that either frequent adjustments had to ture and aggressive in marketing elec- rtx:hargeable batteries and a range in be carrh~] out, or ~,parate measurements tronic tachex~meters in the 1980s (Fig. da)hght of up to Itlkm. Modulation made for angk.,s and distances. 12). :~ But one which was outstanding in trequt,ncies Umpo,,t~t on the amplitude accuracy, stabilit% great weight and high of the carrzer wave by a Kerr cell) were The .~'cond and more satisfactory way cost was the Zeiss (Oberkochen) Elta2 har~ged, null-meters ~ere .~'t, and b~k- of combining electn~ptical EDM with (intr(~uced c. 1980). This instrument has ings were made all by hand I re,call that angular measurement was to design a sh.~d up to usage ~m many under- it h,~k at lea,,t .~1-40 minutes to complete completely new tacheometer in which a graduate field courses, research grants a ~,et of readings and calculate the microproces.,~w controlltxl automatic re- and contracts. It combines the highest mea-,t=red distance. During the 19o0s gistration and display of both angle and standards of opto-mechanical and elec- and 1971)s electro~phcal EI)M instru- distance measurements. This meant that tronic engineering at a time when one or ment,, became smaller, lighter, more circles had to I~' ct~h~ and ~anned by the other was often compromised.

(~ Bulletin of the .cx-ientificInstrument Society No. 72 (2iX)2) r>x ; a.,

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o ~ =.L':,' .:'..:=:: ....

(~ .... ,..,.,, :1 o i~ 72', ?,.::'L:." II.:i'...~:'i::.;- .... -<

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,i <. Fig.14 Telluromct~MP~42 assembly la~uL Tellum~, Oper- ator's Manual, c. 1961. Personal records.

Fig.13 Isiola ba~, Kenya, 1957. Disposi- tion of the measuring par~. J.F. Bell.

With modem electronic tacheometers it sham College, London from 1620 until instruments, 'Master' and 'Remote'. Mea- is no longer necessary to level the his death in 1626), which was 66 feet surements were made at the Master which instrument carefully because tilt sensors long, made up of 100 links, or the transmitted the signal to the Remote correct for the effects of residual inclina- engineer's chain, 100 sections, each one where it was detected, amplified and tion of the primary axis on horizontal foot long. Folding the chain, and throw- returned. Two-way voice communication and vertical angles. Compensators, ing it out, were techniques that had to be was I:X~ssible by RF modulation of the which had come into use in opto- learned, the latter action, if carried out on signal. For the first time it was l~ible to mechanical levels and theodolites, re- slippery ground, reminded the thrower communicate between trig. ix~ints up to moved the need to adjust a bubble to set of the law of con~rvation of momentum. 00 miles apart by means other than a vertical index when taking vertical Chains were used with magnetic com- heliographs, which were still necessary circle readings. Manual b(~king became pass, or theodolite, or on their own in for angular observations. I remember the superfluous when registered data were triangulation as control for large-scale telephone-type handset was very difficult corrected, transformed, displayed on pla~s. At the other end of the accuracy to replace inside the narrow slot at the LCD and LED array panels and stored spectrum in distance measurement was base of the instrument, but that was a in removable memory modules. The the measurement of baselines in national minor irritant. Aiml~st overnight fidiow- surveyor by manual keyboard entries primary triangulation networks using ing 60 man(sic)-months of measurement can now control what measured data invar tapes in catenary. Procedures were of the Isioio 13-mile baseline it was are recorded, displayed and stored. complex and rigidly enforced in a possible to measure distances five times Additional a~sociated data such as the hierarchy of resl~msibilities. This parti- longer to an accuracy of a few centimetres names or numbers of the survey sta- cular contemporary diagram (Fig. 13) in under 00 man-minutes. tions, atmospheric parameters for correc- shows the disposition of more than bO tion of vertical angles and distances, and personnel and their apparatus for the The Tellurometer MRA2 was .,~xm intro- ctxwdinates can al,~ be entered and measurement of the 13 mik~ of the lsiolo duced with many improvements, but used in the field to compute data base in Kenya in 1957. Progress was at microwave EDM I~rought new challenges specific to the purp(~e of the survey, the rate of a mile a day. The di~repancy to surveyors who until then had used such as 3D ct~wdinates, areas, and the between outward and return measure- only opto-mechanical instruments. We lengths of inaccessible lines. Some in- ments was a little more than half an inch, now had to take readings in the field struments no longer need special reflec- or 1 part in I,~X),tX~O. from a cathtxte ray tube and be aware of tors for EDM and can find automatically the physical danger of replacing a still- targets previously identified or can be At the time the lsiolo base was being smouldering klystron valve. During UK operated remotely by a radio link which measured, the first instrument to make leave from Nigeria I went to Strutton allows data transfer in both directions. use of frequency-modulated microwaves Ground in Victoria where Tellurometer Electronic tacheometers are now devices for EDM was in prt~uction. Developed in UK Ltd. had their workshop. Under the fi~r measurement, computation and set- the late 19~)s by T. L. Wadley at the South guidance of Jim Gowans and Brian ting-out in the field. African Scientific Research institute, the McGuigan ! learned a little about the Tellurometer was ~n accepted as the Microwave EDM MRA2 circuitry, and what to attempt by main instrument for accurate and rapid way of repairs when certain malfunctions We were taught chain surveying using measurement of distances in first and occurred (Fig. 14)." The instruments were either Gunter's chain (after Edmund second order control surveys. The Tellu- so new that the operating manuals were Gunter, Professor of Astronomy in Gre- rometer Mkl consisted of two different still mainly in manu~ript. With some

Bulletin of the Scientific InstrumentStx'iely No. 72 (2002) Fig.10 l,Vihf A7 ster~,lotter. Manu.fiwturer ~ publicathm.

Fig l'~ P, d;,t,mt~,, MIdttl,lc~ 7 Im,i¢ct0r photo£nmmu'tric ph~tter. ~ro,t h,xtl~.~k of lol~graphical Surveying, 4 '~ editum (HMSO, la',,h,n. Ioo.g~. apprehension I returned to Nigeria with problem to HQ in Lagos by telegram and get~ietic calculations t(~k many hours to the ta~,k of u.,,ing ]ellun~meters with a wt,~k later I picked up a reply that Jim complete. In the l~'J0s I spent 24 hours another .,,urvevor, Jacob Daramola, to re- Gowans was believed h~ be on his way to (not c(mtinuously) using a Brunsviga to define the .~'ale of the Nigenan primal, Port Harcourt from the UK to calibrate calculate (and check) the inverse of 35 x 35 triangulation by measuring the sides of a the f~o~]uencies of Shell's [ellurometers, matrix using Choltski decoml~stion. In tnangle at each chain function. ~' We and I should go there immediateh'. A long thtse numerical pn)ct.'s.,~es, every digit mo~e~| camp every few days. We had day and night drive from near Kano to literally was handled by the person doing 240-volt generator~ for charging the 12- Port Harcourt and meetings with Jim the caiculation. Although by the i~)s volt lead/acid batteri,.'s. The Land Rovers Ca~wans after-hours at Shell's HQ .~w mechanical calculating machines were we moved an~und in were also u.,~cl for the frequencies reset to their nominal being made with ek'ctric motors to save battery-charging, but it was not always values and the work continued. turning handles and shifting carriages p~,~ihle to have enough fillly-chargt,d manually, the first significant change to batterits at the tops of the hills where Most of the angle measurements in the these procedurts came with the manu- Nigerian primary triangulation were they were nettled Ancient k'ad-acid facture of the Hewlett Packard HF35 made between 1928 and the outhreak of hath, rie,;, often with crack~.| casings, ~cket calculator (c. 1970). Since that time the Second World War. They were of an were unl~pt, lar headh~ds among,~t the technological change has transformed the exceptionally high accuracy, with aver- l~wters ()n the other hand, the heavier speed and cost of survey computations age triangle misciosurts of about 1" and l-ellurometer was a I~rter's status sym- beyond any realistic expectations Now, none greater than 4". The baselints were bol Quite often ! had to turn in near with an unexceptional laptop PC like the r~d of the .,~lme standard, hence the need de~pair to the circuit notes I had made one ! am using tonight to pr~'ct digital to redefine the .~ale. The average dis- back in London at Strutton Ground to images, it is i~ssible to perform the same crepancy between forward and back- decide what I could do to rectify a fault computation that h~k me 24 hours in the ward Tellurometer measurements was lhat was not covered in the manual. I l~)s, but on a matrix one hundred times ~,hould ~y thal throughout the six years ] ±2.3ppm. Although all measurements the size, in under a second. ~l~'nt in Nigeria in the ]9~k and l~,,0s in were completed within a year, they were common with other .~ur~eyors, not once not u.,~,(I in a recomputation of the whole Photogrammetri¢ Mapping network until 15 years later, by which did I phone the UK, and only local phone Mapping [n~m aerial phoh~raphs was time it was clear that both triangulation cain when in l.agos were possible. carrk~ out in British territories at home Although I had brought out a .~'lection and microwave EDM were becoming obsolete. and overseas using opto-mechanical in- of electrical .',pare parts, it was .~)metimts struments and meth(~s that were quite nece~a~' to find a market ~tall ~lling Computations different fr~m th(~e then used in Europe old radr~, and with the aid of a guide to (Fig. 15)." Tn illustrate this by extremes, a coiour coding of r¢~,i~,tor~ and capacitors Sun.ey computations in the 19~)s were common British stereoplotter was the and an Avometer, seek a .,,er~'iceable carried out using mathematical tables: Multiplex, using anaglyph pr~e~'tion of replacement coml~nent. Finding replace- Chambers' and Shortrede's seven-figure recluced dial~)sitives, adequate for most ment vah ts that worked was iml~sible. tables for logarithms of natural numbers purposes, but of limited accuracy and of trigonometrical functions respec- (Fig. 16)." By contrast, Eun~pean compa- An im~wtant defect developed in the tively; and Peters' eight-figure tables for nits built precision opto-mechanical plot- lellurometers that requirt~] more serious natural trigonometrical functions." For- ters that u.,.~-,d full-size (230ram ~]uare) attention because it directly affected the mulae were computed by hand. All diaFn~stives. They were more costly, more ~ale of the measurements - the .,~de imFnwtant calculations were performed accurate and far more interesting and so puq'~,,e of the pn)~,ct. It was l~.ssible to twice independently using different algo- well-built that some are still in use. u~' the (R rs to compare the modulation rithms or different per.~mnel?: Mechan- Phoh~rammetric mapping has not yet treHuencits of one instrument with th~e ical calculators were u:,~d instead of become entirely digital and automated, of another, but if they were different, as logarithms where p~ssible (it depended despite many re, arch programmes lead- they usualh,' were, there was no facility (nl the form of the algorithm: |ogarithms ing towards that objective. The main for deciding which was wrong (or for sequencts of products and machines reason for this apparent slowness L~ that whether they both were). I rel~rk~ this for sequencts of sums of prCducts). Some it is not yet possible to automate reliably

8 Bulletin of the Scientific instrument S(~y No. 72 (21KY2) Fig.18 Attributed to Zubh'r, Io01. From Ancient I:¢~t,tian Fig,17 Lc.a NR53/L I.I ¢~ 1,2, M,m.t,, Suns~. tn¢. l,h'utsche Verem fiir Vernu~sunesuvsen, 1971. exhibition turer's publication. catah~ue ~X}0 Years of Sun'eying. or extensively the decisions that a human I:,,ing makes when making a map by ka~king at stereo-images. Although re- ¢,'stablishing the geometry of digital or digiti,,~,d images has been largely auto- mated, the interpretation of stereo-images hw mapping purposes has not. A recent important development in photogram- metric instrumentation is the use of images from small digital cameras like the Pulnix camera, interfaced to a portable PC such as the laptop us~.d in this pr¢.~.ntation, to carry out measurements of 3D positions and orientations of engineering components (in manufacture, or under static and dynamic load tests) in real-time to an accuracy of tens of " "a" micrumetres over distances of a few Fig.lg. I.~icaMX94t~)R L)C,PS rrference station. 1.1, 12-ctrannels. metres. This necessitates some smart rt~.rence station or fi~r naz.ixatrm at ,]lhm accurm~. I I,%m with software engim,ering and the location of Act'ut'0de pn~.-,~sm~). Manu~m'turer's publr'ation. ta~t, ts in the image of the camera to an accuracy of about 3(X)nm, or the wave- length of green light. Next we turn from quent satellite positioning systems have few years of research and development. the small to the large. benefited from this scientific work. ways of using the signals for accurate surveying were devi.w~J, e~en though tl~. Satellites and Systems By the time sub-n~*tre gk~al positions preci~ data could not be decoded lh,' were achievable bv lransit Doppler, the removing the preci~ ct~le {easily done b~,' The Soviet 'Sputnik' was hunched the new Navigation Satellite Timing and ..,quaring the signal) to reveal unmodu- year my fellow graduate students and I Ranging Gl~ha I Positioning System (N AV- lated sinu~,dal carrier signals (but at were at the St'hind of Military Survey. We STAR GI~) was becoming operatitmal. twice the frequency of the original) expected artificial earth satellites to have ~am the Transit system was aband~n~'d interterometric and other methods wcre a scientific u~" in geodesy and geophy- and '(.;PS' was adopted by the US Military. u~J to trod the p(~,ltion of one rt~.'eiver sics, but not that they wen.' going to The original Sl~cification by the US relative to am~ther in a 31) ct,~rdinate sweep aside much that we were being I~,partment of Defense (1978) was '... to system to an accuracy of at~ut t(3mm + trained to do and were at~ut to put into provide ~tellites and signals for world- 0".5ppm) or about ~)mm over 100kin practice in far places. The first satellite wide real-time navigation, with i~sitional system to be u,~'d acn~ss the world for errors of the order of l0 metres, tolerant of Now that preci.,~, timing ct~|es have be~ sun'eying was the US Transit System. interference (intentional or not) and cap- made available to makers of n,m-mddarv The Doppler frequency shifts of signals able of being u,,~l when the re~'eiver is receivers, (,15 L', u~'d in ditten,nt ways transmitted from artiticial earth satellites travelling at high speeds (e.g. military. and with different pn~'edun'~ and accura- as they move towards or away fn~m a aircraft)/The timing information ,~,nt out cies h;r many different applications, tor r~'eiver fixed on the earth were detected by the satellih~ was ra~.'t.~ry to meH the example: mapp,ng general path, ms of and u~d to calculate the receiver's specification. It was transmitted by binary vegetation, or .,~lls to an accuracy of Ii) I~sition on the earth. Although primarily bi-pha.,ae m¢~|ulation of i.57~;!1z and metn..'s; surveying utilities to an accuracy for military purl~es, the Transit signals 1.228(,|1z L-band radio carrier signals of .~k'm for a geographical intormation wen., s~.~n u..,ed by civilian organisations (equivalent to wavelengths of about system ((;IS); contnd suneys for mapping for various non-military purp~,s/' Re- 2(k'm) but hidden by a [~eudo-random of rt~aote areas to a ba~,llne accuracv of search into the use of the signals led tn a noi~ code that could" be dect~led only by ±(5ram +2ppm), or to real-time monitor- rapid dt~-rea~ in p~vsitioning em,rs as military, receiver~. Commercial organl~- mg of large structure~ to accuracies of a more accurate knowledge of the earth's tions and rt,'~,arch institutions built re- millimetre (Fig. 17).'~ In Great Bntam, gravity field was obtained through ceivers to pick up (.;1~ signals as they had ()rdnance Sun'ev triangulation station,, observing the satellites' orbits. Sub,,~- done earlier for Transit l~ppler. After a are ob~flett,. IT~,v have been riT, laced b,v

Bulletin of the ~-wntihc Instrument .%~ety No. 72 (2002) q active GPS stations transmitting position- cann~< see a collection of patch-matching 16. Kern DKRV staff. L Fialovsky, ed., Survey- mg data for nearby mobile GPS users with algorithms for digital image pn~essing inX Instruments and Their Operating Principles data l~sted on the Web for post-proces- making up a desirable lot at auction, or (Amsterdam: Elsevier, 1991). sing. filling a museum display case. As for the 17. Wild RDH. Manufacturer's publication. Conclusions instruments themselves, they are either very large and impossibly expensive to 18. Wild RDH staff. Manufacturec's publica- lion; Fialovsky (note 16). i have described some instruments and bring from their orbits into a museum, or meth,~s in land surveying with which 1 a Bond Street shop window, or they are 19. Watts 'stir-adjusting' level. Anon, How to have had some practical experience in the very dull, displaying only a coloured Adjust M,~ern Theodolites, Tacheometers, levels last 45 years, but have probably omitted Etc. With Notes on the Care of Instruments badge on a surface of bland plastic wha~se (London: E. R Watts & Son, n.d.). more than I have included. Looking back only purpose is utilitarian durability, now it can be seen how extensive have with no ornamentation to delight the 20. Parallel plate micRnneter [or CT&S $500. been the changes my professional collea- Textbook of Topographical Sunning, 4'h Edition eye. Perhaps this GPS reference station (London: HMSO, 1965). gues have accepted and put to gca~d use. (Fig. 19)* will be pursued through the Such acceptance was not easily gained. In auction rooms of the world by enthusias- 21. lnvar precise levelling staves. Gradua- the early days of short-range EDM, tions: L 1/50 foot; M 0.5cm Anon. Hmv to tic collectors of late minimalist design Adjust Modern Theodolites, Tacheometers, lank'Is routine measurements in the field were scientific instruments, l shall not be Etc. With Notes on the Care of Instruments regularly checked by surveyors using amongst them. Will you? (London: E. R. Watts & Son, n.d.). steel tapes. Academics assessed random Notes and References 22. Zeiss (Oberkc~len) Ni2 section. Manufac- errors and identified sources of systema- turer's publication. tic errors in the new instruments and I. Ancient Egyptian Surveying. Deutsche devi.~l ways of reducing them by Verein fiir Vermessungswesen, 1971,exhibition 23. Zei~ (Jena) NiO02 geodetic level. M.A.R. catalogue 54}(}0 Years ~" Sun,eying. Ct~er, Modern Ttwodolites & Lez~ls, 2rid edi- calibration and measurement techniques, tion (Lm~on: Granada, 1982). as they had done for mechanical and 2. Polimetrum of Waldseemeller. G. Reisch, opto-mechanical instruments. The eco- Marfanta phth~phk-a, Freiburg, 1508);Heron's 24. AGA Geodimeter 6, 1964. Advertisement nomic advantages that could come from dioptra, Alexandria,c. I00 BC. Hera - Opera Vol in Sun W Rev/eu, 18-140 (April 1966). IlL I~3. Bodleian shelfmark 1996 e 672/3. the speed of the new instruments were 25. Such as the AGA Geodimetet i16 with only achieved after their accuracy had 3. See lot instance the Heinrich Stolle theo- Wild ]'2, in Fialovszky (note 16). been generally accepted by the professkm dolite, 1600-1613. 175ram circle,gilded brass. 26. Coded circle, HP 3820A 'Total Station' through shared experience and predomi- Nat. Tech. Mus. Prague. Also azimuthal sun- 1977. Cooper (note 23). dial,diagrams and scalesfor trigfunc~ms (sin, nantlv sceptical, rather than reactionary, cos, tan, sec). 27. HP3820A 'Total Station', in Cooper (note attitudes. Land surveyors are not natural 23) neophiliacs, but once'they are convinced 4. W. Derham, ed., Rv4,ertH~mke's Phih~phi- cal Experiments and Obsen,ations (London, 28. Sokkisha (now Sokkia) ~ 'Total Sta- that a new instrument will produce 1726). tion', c. 1985, 2" angles, +/- (3ram + 2ppm). results more economically than before 5. The fifth and last of the 'Great Theodolites' PrimaW axis tilt correction, 2kin range in and as accurate as necessary in relation to average conditions, 1 prism, 3.4kin ditto, 9 commi.,~kn~d from Troughton & Simms in their purpose, then innovati~n~s are taken prisms, 7.6kg with battery, no case. Manufac- 1857 for trigonometrical survey of ]ndia. turer's publication. up and u,~'d. Completed in 1867, but never used. Now in South Africa. First one made in 1787 for trig. 29. Tellurometer MRA2 assembly layout. ! supp(r-~ ! should now admit that the between Lond~m and Paris tg'~,ervatories. Used Tellurometer Operahrr's Manual, c. 1961. Personal title of my lecture hides the fact that with 2rid for GB trig. 36-in circles, 660kg, 10 records. much has not changed. Although it is porters. Courtesy J. R. Smith. 30. N.J. Field, 'Primary Triangulation and true that binary bi-pha~ modulation of 6. As shown by the Leica GPS System 500. Traverse in Nigeria', Survey Review, 18S radio signals ks now commonplace in Manufacturer's publication. (1977), pp. 109-118. satellite positi,ming, a graduated metal 7. Cooke, Tmughton & Simms 5-inch circle tape can be said to carry a binary 31. TM projection coordinate conversions. C.es~leticTavistock theodolite, in G. Bomford, Textbol~ of Topographical Suncying 4" edition modulation in the form of its gradua- Geodesy (Oxford, 1952). (London: HMSO, 1965). tions: at any position along its length, 8. Cooke, Troughton & Simms's "Tavistock' there is either a graduation, or there is 32. Block& Andersou Facit N. L. X. calculator. theodcdite ('I"65).Anon, n.d., but prior to July Textbook of Topographical Sun,eym{¢ (note 31). not. Another constant is geometry. This 1949, described in Theadolite Des~¢n & Con- 400-year-old sketch (Fig. 18) of plane struction CI'&S, York. 33. Williamson Multiplex 7 profecto¢ photo- tabling also illustrates the principle of ~rammetric plotter. Textbook of Topographical 9. Wattsvemiertheodolite. Anon, n.d.How to 5un,ey. ing (note 31). satellite positioning in three dimen- Adiust MMern Theodolites, Tacheometers, Lez¢ls sions." In the rush to increa~ speed Etc. With Notes on the Care of instrunwnts. E. R. 34. Wild A7 stereoplotter. Manufacturer's and accuracy, craftsmanship has been Watts & Son, London. publication. replaced by efficient mass-production 10. Wild 1"2 theodolite. Textbook of Tota,~raphi- 35. Transit Ek,ppler accuracies. G.W. Hoskins, and as~mblv of reliable, lightweight cal Suns~.mg, 4m Edition (London: HMSO, Proceedings 2nd S~nposium on Satellite Doppler opto-mechanical and, subsequently; elec- 1965). Positioni~¢ 0anuary 1979), pp.21-37. US DMA & NOS tronic hardware. In using the instru- 11. Wild T210 theodolite. Manufacturer's ments, skilled manipulation has given publication. 36. Leica SR530. L! & I.,2, Manufacturer's publication. way to management of automated data 12. G.J. Strasser, 'Heinrich Wild's Contribu- processing. Craftsmanship in making tkm to the Development of Modem Survey 37. From 1971 exhibition catak~gue 5000 .~ars individual opto-mechanical instruments Instruments', Sunny Review 18-140 (1966), ofsuncying (note 1), attributed to Zuhler, 1601. pp.26~268. has been replaced by ingenuiO,, in writing 38. Leica MX9400R DGPS reference station. and installing robust computer code. 13. Wild "1"2section. Manufacturer's publica- LI, 12-channels, for navigation at 30cm accu- Such skill is not tangible - on the contrary, tion. racy (15cm with Accucode processing). Manu- factumc's publication. the greater the skill, the less it is noticed, 14. Wild ]'4 astronomical thtmdolite. Manu- except by the new connoisseurs of code- facturer's publication. Author's address: writing. Although algorithms have found 15. gem DKRV vertical staff tache~nneter. J.R 85 Lancaster Road their way into specialist textha~ks, there Smith, Optical Distance Measureraent, (L~mdon: St Albans, Herts ALl 4ER is as yet no collectors' market for them. I Crosby Lockwood, 1970). m a.r.cooper@ci~.ac.uk

10 Bulletin of the Scientific im,trument Society No. 72 (2002) The Special Loan Collection of Scientific Apparatus, South Kensington, 1876 Part 1 The 'Historical Treasures' in the Illustrated London News Peter de Clercq

galleries between Exhibition Road and Queens Gate (then Prince Albert's Road), :~:5.: CATALOGUE . roughly where now the Science Museum and Imperial College are. The total Olf Yl~ exhibition space was roughly 10,000 square meters, and there was also a :8PECI LOAN COLLECTION OF Conference Room where lectures were delivered on the various sciences, often SCIENTIFIC APPARATUS with explicit reference to the apparatus displayed (Fig. 2).2 Jt T

The Loan Collection was dispersed again, • ..,.801~H K~SIg6TON ]hqJSl~]¢ as the majority of the exhibits had to be returned to their owners, although some .r.~:,: .. MI)CCCLXgVL of them were added to the science collections of the South Kensington Museum, from which eventually THIRD I~DITIOI¢. emerged the Science Museum, separate from the (applied) arts which became the Victoria & Albert Museum. What re- .J . , mains, however, is the impressive 1084- page catalogue, which records in minute detail the thousands of instruments that had been brought together in this extraordinary exhibition from all over the United Kingdom and the European LONDON: Continent. Never before had the general "~ lqffgYliD BY OSOlU;l¢ g ~ AgD W'R.MaM Sl'oYrlBwOODIL P~r'lrl~l~l ~ ~ q~SIL~II ~ )llgOgl~ M4,1rlrJnMr. public been able to see the instruments • - ...~j.~ • IN~ IBl W~/i'tlrl IR'tYlflW~ff Ol'IRtl and paraphernalia of science in such

~~,,~. 1877. profusion and so systematically.

During my years at the Museum Boer- haave, i developed a fascination for this Fig.l Title page of the 3rd edition of the Catalogue of the Special mammoth exhibition, and especially for Loan Collection of Scientific Apparatus at the South Kensington the antique instruments. I found it Museum, published in 1877, after the bulk of the objects had been intriguing to consider that, more than returned to the lenders. This edition is the most complete record of this half a century before the establishment of extraordinary exhibition. It lists 4570 items and runs to 1084 pages. the museum where they are now dis- played, Leiden University had sent Christiaan Huygens's planetarium, tele- Introduction where th~ are treasuredas sacred relics, as well scope and object lenses and's Grave~ as apparatus in present use in the laboratories. sande's air-pump - to mention just a few - The Special Loan Collection of Scientific across the North Sea? My move to Apparatus (Fig. l), exhibited in South Or, phrased somewhat differentlyin the London in 1999 enabled me to explore Kensington from ]5 'h May to 3(P Decem- same introduction (p. xiii): the Special Loan Collection 'at source', i ber 1876, has often been discussed, both have spent many happy hours locating, as an impui~ to the creation of the it u¢s desired to obtain not only apparatus ~r sifting thnmgh and interpreting masses Science Museum and as a significant teaching and far imwsh,~atam, but also such as of printed, manuscript and pictorial moment in the growth of interest in p~r,sessed historic interest on account of the material and object acquisition data antique instruments.' The initiative lay persms by whom, or the researches in which, it related to this event. Most of this with the Science and Art Department of had h~n employed. material, naturally, is held in the Science the Committee of Council on Education, Museum and its library and archives, the organization was the work of a large It was intended from the outset to give and I gladly acknowledge the support committee of prominent men of science, the Loan Collection an international that [ received in my research from its and it is impressive what they managed character, but it was distinctly not to be members of staff, especially Nell Brown, to bring together. The vast majority of another trade fair in the tradition of the Kevin Johnson and Mandy Taylor. An exhibits were contemporary, but from the Great Exhibition of 1851, but a scientific invitation to give a talk for the Society's start the organizers insisted that the Loan exhibition. The arrangement was to he AGM on ll July 2001 was a first Collection - to quote the introduction to not by countries but strictly according to opportunity to present my findings, and the catalogue (p. ix): a general subject classification. While it I decided to concentrate on a well-known had originally been hoped to hou~ the engraving, captioned 'Historical Treas- was to include not only apparatus and objects exhibition in the South Kensington ures in the Loan Collection of Scientific from manufacturers, but ai~ oblects of historic Museum ~,"" " Exhibition Road, in the Apparatus, South Kensington', published interest from museums and primte cabinets, end the . r..,atus was displayed in in the Illustrated London Neu~ of 16

Bulletin of the Scientific Instrument Society No. 72 (2002) ll What follows is a running commentary soo'rl zlxsesulroN iuslou. "'~]] on the objects depided, mainly based [-OAIM QOP. LIOTIOM OP ICOIliYlfflO A*II'PA~AqruI IIFir. / on the information supplied by the catak)gue, although the text leaves no doubt that the reporter had actually looked at them closely. The following week, the periodical printed a further one and a half column article, headed ' Ilflll li r I { i ~l.I ,11. ; Scientific Instruments Collection; which LI. I i41; ...... r-/ ° ...... : '~., ]Oriml[ ...... -, ...... ~,,~T,a~,J ±] ~ o: iI •I ...... ~ I N'~ ...... ,:.~-P-~ " ;B / The history of inventions for the application of moti~ power, more especially of the early steam- enl~ines, is exemplified in the Special Loan IB . ~ iIj ~ ...... ~}'4 ,~ ,r / Collection of .Scienti~c Apparatus, South Ken- sington.

.i ! ~1~ ...... ~.:..t ._._ _. q, -- /

p~ll I "" Ir This time, the emphasis was on technol- F---w .... ,,0.. ~ ,~-11 . I - _ ~ ~... ~ ogy, which was also well represented in the Loan Collection. The text was again a I:, '~ ...... ~ ti '~"~' running commentary on a full-page J " ; I . a~-~,~--r~"'r'~ ; i~ l engraving (Fig. 4), and concluded with i~ I : ...... ~LJ -];: P_ / i :~ I ¢ ...... ~,~ J':'t ~ / some rectifications to the captions and "-~ I ,-'Y" .: ~|~!.. e"~,--9" / numbering in the engraving published in "z=';" ~ ; i~ " ~: / ._~ the previous issue. 7) -' ~='~.~.-..r-_ ~-.;~---=-.~r .... I :' i ~ I / J Identifying the 'Hi~orical Treamures' Fig.2 The scienti~c apparatus u~as displayed in a series of narrow galleries to the south and u~t of the R~. al Horticultural Gardens, roughly u~re nou, the Science Museum and Imperial For the twenty-seven exhibits shown in Gdlege are. in the right-hand bottom corner, the 'Entrance to the Museum" is the original the two engravings, the following ele- public entrance to the South Kensington Museum, just north of the Henry Cole wing of the rllw2nts are given: Victoria & Albert Mu~um. - the caption printed under the engrav- ings (bold) - the entry plus comments (sometimes September 1876' (Fig. 3). This article is an read of the Queen's visit on Saturday 13'~ abridged) in the Catalogue of the Special expanded version of that talk. May, 'after which the exhibitors of the Loan Collectionof ScientificApparatus at the instruments specially noticed were pre- South Kensington Museum, third edition Of course, the antique instruments sented to their Majesties'. The following (1877) (italics) singled out by this London periodical Monday, the doors were opened to the - where applicable, pertinent additional were only the tip of the iceberg, and in public, which had free entrance on Mon- information from the columns of the later articles I shall return to the Loan days, Tuesdays and Saturdays, when the Illustrated London News Collection and give a full list of the galleries were open from I0 to 22 o'clock, - modem data on the object, such as hundreds of historical instruments that whereas 10 pence were charged on the present location, modem description and were displayed. That will also be the remaining days of the week, when the information on provenance or identifica- proper place to di~uss the many pub- exhibition would close at 18 o'clock. The tion problems. lications that appeared in connection conferences and evening lectures were with this event, as well as - another also announced? A month after the open- 1. Tycho Brahe's Quadrant hobbyhorse! - the electrotypes and other ing, an anonymous reporter visited the copies that were made on this occasion of exhibition. While he found the lay-out and Catalogue p. 398: a number of the historical instruments. labels unhelpful, he commented on some of the exhibits in detail, and it is interesting 1775. Quadrant, formerly belonging to that he singled out only historical objects, Tycho Brahe /Royal Museum, Cassel The Special Loan Collection in the rather than the modem apparatus which (Director, Dr. Pinder) / This instrument is Illustrated London News was much better represented.* And this the astronomical quadrant of Tycho Brahe. was only an appetizer. The issue of 16'h The altitude quadrant, as well as the Founded in 1842 by Herbert ingram (1811- September contained an article entitled azimuth divided circle, are made of brass; 1860), the weekly Illustrated London Nez~. Loan Collection of Scientific Apparatus the first is divided into sixths of a degree, was a popular source of instruction for the which, over three densely printed col- the second into whole degrees, which can be Victorians. Attractively produced in large umns, concentrated entirely on the histor- read by a simple pointer, but without folio format, with specially commissioned ical exhibits. 7 The article begins thus: verniers. The radius of both circles is w(~ engravings, it covered world events 40 cm., and the stand is constructed of as well as .~)ciety and culture in a wide cast iron. .,~n~, and this included modern develop- In the Official Handbook to this Exhibition at ments in science and engineering.' South Kensington it is stated, among other thmxs, that "it u~as desired to obtain objects of Kassel, Museum fiir Astronomie und Although eclip~d by the Centennial Technikgeschichte. Exhibition at Philadelphia, which was historic interest from museums and private cabinets, u,here they. are treasured as sacred Altazimuth quadrant, c. 1560, presum- held at the ~me time and was given relics." In our page of Illustrations, with the ably made by Eberhard Baldewein, also extensive coverage, the Special Loan folhrwing descriptions, we present some of these known as 'Wilheimsquadrant' (Land- Collection was repeatedly mentioned in treasures, and giz¢ a brief histor#cal account of grave William IV observed with Tycho its columns. During the first weeks, we them. Brahe in Kassel)."

12 Bulletin of the Scientific Instrument Society No. 72 (2002) the rn~t important discm¢ries and experi- ments of Galileo, and was constructed by. himself. / The Royal Institute of "Studii Superiori", Florence and 1814. Galileo's Telescope. Object-glass, 38 ram. in diameter; eye-glass double concave, 19 ram. in diameter; made by Galileo / The Royal Institute of "Studii Superiori', Florence

Illustrated London Neus: no. 3 [...] 'Con- structed by himself, in 1610, it is of w(mcl, covered with brown paper, about 5 feet 3 in. long'; no 4 [...] 'It was made by himself; about 4 feet long, covered with leather, ornamented with gold'. . /r. l --

=Ii Florence, Museo di Storia della Scienza, inv. nos 2428 and 2427. They have recently been checked by Albert van Heiden as attributed to i Galileo and made by Galileo respec- tively. 12 _

$. Newton's Telescope

Catalogue p. 411: I 1831e: Original Reflecting Telescope, made by. Sir Isaac Newton / Royal Socie~

Illustrated London Neus: 'On the brass plate on the base is the following inscription: "The First Reflecting Tele- scope invented by Sir Isaac Newton, and made with his own hands in the year 1671". It is about 10u2 in. high, the tubing of cardboard, eyepiece ebony, rings iron, ball and base of wo(~'.

The Royal Society, London. That the Royal Society lent Newton's telescope to the Loan Exhibition was exceptkmal, as earlier, in 1843, it had not allowed its being taken out of its Apartments."

6. Galileo's Microscope iOcchialino)"

Catalogue p. 900: [sub 3510/Galileo's Microscope, then called Occhialino. Only the little tube renumls, the Fig.3 Full-page wood engraving (31½ x 22½ cm) of 21 'Historical Treasures', published in lenses are u~nting / The Roll Institute of the Illustrated London News of 16th September 1876. The objects shown came flora tu,o "Studii Super/or/", Fh,rence. [follows his- private and tuwlve institutional owners in England, Scotland, France, Germany and the torical information drawn from Viviani, Netherlands. The numbers gizcn in the text are th,r,e as listed here. and quotes from letters to Galileo from Prince Cesi and imperiali]. 2. Sir Francis Drake's Astrolabe Greenwich, National Maritime Museum (AST 0172, formerly D.318). llh,strated L,mdon Neus: 'it is of brass and Catah,gue p. 391: Humphrey Cole compendium 1569. The stands about 5 in. high'. 1753. Astrolabe, constructed fi, r Sir Francis association with Drake is unsubstan- Drake, prior to his first expedith,n to the tiated.'" Florence, Museo di Storia della Scienza, West Indies in 1570 / Royal Nm~al Museum, inv.no. 3245 or (less likely) 3240. Greenu,ich. This instrument is said to hazw Bra~ compound microscope, probably 3. Galileo's Second Telescope mid-lq~' century." been preserved in the Stanhope family till 4. Galileo's Telescope" 178.3. It u¢s subsequently presented to King William IV, who m 1833 deposited it in 7. Jansen's Compound Microscope, 1590 Greenu,ich Hospital. Catalogue p. 407: 1811. Galileo's Telescope. Object-glass, Catalogue p. 9(~): Illustrated London Neus: 'It is about 9 in. 50 ram. in diameter; eye-glass, piano- 3510. Comt~,und Micr(~.~'olw, inzwnted arrd high'. concave, 23 ram. in diameter. It served fi,r constructed al~mt 159) ~ Zacharias ]ans-

Bulletin of the Scientific Instrument Society No. 72 (2002) 13 !

F

Fig.4 Full-fag," u~t ,'ngraz'ing ¢31 z/, .r 22z9 Cnl~ of six 'Historical Treasures'. published m the Illustrated Lxmdon News of 23rd September 187o. Bottom h'ft-hamt ,orn,'r art" i'on Guerl,-ke's air t,ump attd Macdebur~ h,'nlispheres fr,,m Brunswick. and top rtght Newcomen'.; steant englnc from G/,]sg0w.

~'. Sl,cct,lch'maker. ,it Alhtdh't,ur,¢h. Nether- 8. George Stephenson's First 11. Pascal's Adding and Subtracting lands / The Scientific St~ietu ,,f Zcehmd. Safety-lamp" Machine, 1642 A ftddh,bl, rs.,It 9. Third Safety-lamp 10. Davy's Improved Safety-lamp Catalogue p. 12: Ilh,.tr, lt,'d la.l,ton Nca's: 'It is a rough into 41. Pascal's Calculatm¢, Machine ~1642) / tube, with glass lens at each end'. Catalogue pp. 876-878: Con.q'rvatoire d~ Arts et Mdth'rs 3408. Collection ,,f Miners" Lamps, ,,f Mnddelburg, Zeeuws .Mu~um various d,'sagns I N,,rth of England lnstitufi" Paris, Musde des Arts et Metiers, Paris, ~'t of four tubes with lenses, date ,¢ Mimng and Mechanioll Engineers [over inv. no. 823-1. uncertain, attributed to Zacharias Jans- 40 different lamps, dated between c. 1816 Pa~aline (adding machine), 1652 (writ- sen. ; ' and 1876]. ing on label inside box: Esto probati mstrumenti Symbolum luw. Blasius Pa.,~'al I-hns instrument, and a tele~-ope [now In combination with the detailed text in Arpernus inventor. 20 May 1052), acquired Ioq?]. were pre~,nted to the museum of IIh,,trat,'d hmd,,n Neus, the lamps de- bv the CNAM (Con~rvatoire National the Zeeuws Genootschap der We- picted can be identified as" des Arts et Mbtiers) in 1814. ten,~-happen in 18~-,6 by a private in- dlvndual. I..'4niider from Veere. They had 8 = 22a: St,'l,he,s,,n CGeordi,')/glass. u,ith In 1642, Papal had reached an impas~ been in his family for se~ eral generations l,ertbr, lted sln,'ld /.first exp,'rim,'ntal in his attempt to make a practicable and ssere traditi/,nallv believed to be the machine. A first ~tisfactorv machine earliest forms of inventions by Zacharias 9 = 18-20: Sh'ptn'nson ¢Geordiel / glass was available in 1645, and presented to lans~'n. I-he mu,.eum authorities invited surromhh'd I,y ,~auz,'/ recent his maecenas the Chancellor Seguier profe,,~r l'ieter Harting of the University (al~ in the CNAM). After that Papal of Ltrtx-ht to examine the instruments,;" 10 = 10: Common Dm,~¢ /sinc, le gauze. began constructing them in a small and twenty years later John Mayall, original tyl : / ahmt 1820. .series, for which he acquired a mono- lunior, pur~qy made a visit of inspec- poly in 1649. He sold some, and tion to Middelburg and reported that he I do not know what became of the presented some to illustrious persons, would 'unhesitatingly affirm the micro- collection of .safety. lamps, sent by the including Christina of Sweden. The fact .,~-ope to be older than the .,,,,-called North of England Institute of Mining and that 'about ten' specimens survive Galilt~ micro~'ope'.'" Mechanical Engineers.-"' suggests that in spite of the high price

14 Bulletin of the Scientific kt~trument S(~--iety No. 72 (2002) of 100 Francs, quite a number were the expense of so many conductors made the Illustrated London News: no 16 '[...]The constructedY ~stera ¢conaraically impracticable.~ whole is about 14 in. high'. London, Royal Institution. Payen describes eight Pascalines (includ- It is not certain that the telegraph in the ing h)ur in the CNAM), and knew a few Munich museum is the ~ame as that sent 17. Forbes' Apparatus others in private ownership." The ma- to South Kensington in 1876, nor that chine exhibited in South Kensington either of them is the first one that the Catalogue p. 316: must be the 823-I, as the engraving inventor had presented before the Bavar- 1342. Apparatus by. which Forbes procured shows that it had six functions, while ian Academy in 1809. This is because an Induction Spark from a Natural Magnet. all other seven machines catalogued have Sommerring made several telegraphs Trans. R.S. Edin., 1833 / Uni~sity of several additional functions. between 1809 and 1820. After his death, Edinburgh his devices were guarded by his cx~usin 12. The "Napier" Bones for Division and Thomas Carl Sommerrmg (1821- Frank- Illustrated London News: 'It is of 4 in. of Multiplication, about 1700 furt 1894), presumably the .same as the K. deal, a large cork, secured with sealing (the List of contributors in the catak)gue wax, from which wires proceed. The Catalogue p. 8: gives as initial:C.) Sommermg, Frank- separate part is a wire through the centre 28. "Napier's Bones" or Rods/Made about furt, mentioned in the catalogue, who of two corks'. 1700/Dring and Fage / lm~nted by Baron aLso sent no. 1653. The Voltaic Pile, then Napier, the originator of logarithms, used for used for the abo~', together with the I0 Edinburgh, National Museums of Scot- pe~rming division and multiplication. original silver,and 10 original zinc plates land. and 1654. The Original Conducting Wire, as London, Science Museum, inv. no. 1876- it was made under the direction of the James David Forbes (1809-1868) worked 931. disco~wer in 1809-1811, and tested in the in physics and geology, and was Leslie's Engli~ set of cylindrical Napier's bones, Isar, both not shown in the engraving. successor at the chair of natural philoso- early 18" century.~ His widow passed the Sommerring phy at Edinburgh in 1833.= The firm of Dring and Fage, 19 & 20 apparatus to the Physikalische Verein in Tooley Street, London, was represented Frankfurt, which in 1905 donated 'die 18. Galileo's Air Thermometer by a variety of modern mathematical ersten elektrischen Telegraphenapparate' instruments, hydrometers (of which sev- to the Deutsches Museum. ~ Catalogue p. 256: eral were characterized as 'obsolete') and [No cat.nrl Air-Thermometer, in the form thermometers. Evidently they owned this 14. Faradays Magneto-electric first gh~,n by. Galileo I The Royal Institute of historical calculating device, which after Induction Apparatus "Studii Superiori",Florence (follows histor- the exhibition they presented to the hal information). museum. Catalogue p. 382: 1733a. Siberian Loadstone and Spark Appa- Florence, Museo di Storia della Scienza, 13. S6mmering's Electric Telegraph ratus. This u~s the loadstone emplowd by my. no. 2444: Thermoscope, 19~ century. Faraday in his experiments on nulgneto- Glad. Height 460 ram. Modern copy of Catalogue p. 346: electric induction, from which he first the instrument for measuring heat and 1652. Electric Telegraph, oraginal apparatus obtained the induction spark (See Exp. cold, devised by Galileo during his years as it u~s made under the direction of its Researches, t,ol. IlL / The Council of King's in Padua. ~ original discoverer, Th. SOmmering, in College, London Miinchen, 1809 / K. SOmmering, Frank~rt 19. Dalton's Mountain Barometer and Illustrated London News: 'The base is 20. Dalton's Apparatus for Testing the 1655. Alarum belonging to S6mmering's Tension of Ether Vapour telegraph /K. SOmmering, Frankfurt covered with red cloth; the supports are of ebony; the loadstone is contained within the picture; the helix, immediately Catalogue p. 564-5: Illustrated London Naes: 'It was the first under and in the centre of the bar of iron, 2396 no. 1 is Dalton's mountain barometer, electric telegraph worked by galvanism, is covered with red leather; the whole with accompanying thermometer, made for with a Volta pile, silver and zinc plates; about 22 in. high'. him by the late Mr. Lauwnce Buchan ~. about 9 in. high'. Manchester. Tire barometer is ¢nch'~,'d in a u~den case, u~ich Mr Dalton u~s accus- Londim, Science inv. no. Munich, Deutsches Museum (but see Museum, 1949- tomed to carry, in his hand. qualifications below). 293, acquired from Kings' College, Lon- and Electrochemical telegraph of Samuel don. 2396 no. 17 is an apparatus used by. Dalhm Thomas Sommerring, 1809-11.u Faraday Magnet and Coil. for the determinaticm of the tension ~ the z~pour of ether, and is intereshng as bring Samuel Thomas von S(~mmemng (1755- lS and 16. Faradays Later Apparatus the instnonent by. means of which Dalton 1830), best known for his work in arrived at one of his most important medicine, comparative anatomy and Catak~,ue p. 381-382: experimental laud, C.) ge~lerally knmen as anthropology, 1733. Original Apparatus with which Fara- Dalton~ law of tensions, since ~lmm by. day obtained the Magneto-Electric Spark / Regnault nor to be rigorously true [with observed that electric current pa,~ed thn~ugh an The Royal Institution of Great Britain descriptionl acid solution caused bubbles to appear lelectro- [follows description, with reference to lyric dccompasitum of water into its elements, Phil. Trans. 1831] Entry 2396, "Atg~aratus emph,yed by. hJhn hydrogen and oxygen). He in1~nted a telegraph and Dalhm in his Researches', otmtributed by system using this principle, u~aich u,~ed 26 parallel wires to transmit the letters of the 1734. Faraday's original Apparatus for the Council of the Literary and l)hik~ - alphabet a distance of up to tu~ miles. He a,en Magneto-Electric Induction by a permanent phical Society, of Manchester, contained de.~'rihed an ingenious alarm to alert the magnet / The Rc~al Institution of Great 52 objects, described in detail. John receiving operator (This uws rrallv the first Britain [follows description, with refer- Dalton 0766-1844) became a member of relay, although not electron~chanicah Hm~ver, ence to Phil. Trans. 1831]. this S(~iety, in whose premises he was

Bulletin of the Scientific Instrument Society No. 72 (2002) 15 given accommodation for teaching and B.L. Vulliamy and found 'an unsophisti- [25.1 The Parent Engine of Steam research. The Society concentrated its cated old clock bearing the date 1348 and Navigation contribution on Dalton's research appa- the mark RI,'. At their suggestion, it was ratus: 'Most of it was made with his own washed, brushed, treated with boiled Catalogue p. 490: hands, and that which is exhibited has been lirLseed oil and placed on a pedestal in 2150. Parent Steam Engine, madefor Patrick chosen as illustrating this fact, and as the armoury. Soon after its discovery, Miller, and used by him on the lake at indicating the genius which with so insignif- Esq., drawings (reproduced in Evans' article) Dalswinton, 1788. / Bennet Woodcrofi, icant and incomplete an experimental eqmp- were made, possibly by Octavius Mor- F.R.S. (follows historical information). ment was able to produce such great results. gan. In 1872 it was deposited on loan The Society has in its possession a large with the Patents Office Museum, whose London, Science Museum inv. no. 1857- quantity af apparatus used by Dalton, rn~t collections were later incorporated into 52 (-- Symmgton's Marine Engine). a of which however consists of electrical the South Kensington Museum. apparatus, models of mechanical pouers, [?J~.l Ntwcomen's Steam Engine models of steam engines, air pumps, a The clock aroused much interestamongst Grqcorian telescope, and other apparatus of antiquarian horologists, but there is a similar kind, which mas either hmght or Catalogue p. 451: much uncertainty about it. According to [no cat. number] Newcomen Engine, presented to him. It has not been thought one story,the clock had been carried from necessarv to exhibit these, but rather to shaw repaired by Watt, the property of Glas~om, France by an officer of a Highland University / Sir William Thomson the home-made apparatus with u~ich Dalton regiment after Waterloo, but left behind obtained his most remarkable results'. in Dover, where it eventually ended in (p. 564). Illustrated London News: 'Watt's chief the castle by way of safekeeping. The improvements in the steam-engine were year 1348 was reputedly placed there IllustratedLondon Neut,: '[no. 20 is] made that he excluded the air from the after 1851 by a local tradesman when the cylinder, made the engine double-acting, by him of deal, the central figures and visit of Smyth and Vulliamy was an- lines being written on paper, which is and condensed the steam separately. The nounced; it was an attempt to make it last improvement was suggested to his pasted on. The originals of 19 and 20 are more interesting for the antiquaries, but about 3 ft. long'. mind in the winter of 1763-4 while soon after their visit it was removed repairing Newcomen's engine belonging againY to the Natural Philosophy class of the The two instruments depicted here may University of Glasgow. Of this machine no kruger survive. There is some Dalton The engraving in IllustratedLondon News we give the Illustration'. material in Manchester and in the Science of 23'~ September 1876 shows another six Museum, London, but most was lost 'Historical treasures', unnumbered. Here, Hunterian Museum, University of Glas- when an air-raid destroyed the Society's the emphasis is more on technology. building in 1940; fortunately, it was gow. described in two pre-war publications. ~ Probably made by J. Sisson, London, 122.1 The Comet, First Steam Boat on the mid-18'h century.~ Clyde, and 21. Ancient Swiss Clock, bout 123.1 The Original Engine of the Comet Dover Castle [27.] Otto yon Guericke's Air-Pump, the Magdeburg Hemispheres Catalogue p. 490-91: Catalogue p. i16: 2178bc. Original Whole Model of the Steam Catalogue p. 158:~" 491. Ancient Striking Clock / H.M. Commis- Boat "Comet". Built on the Clyde by I. Wood 606. Otto yon Guericke's Air Pump / sumers of Patents. This clock is of Swiss for Mr. Henry Bell, at Port Glasgow, 1811. "Collegium Carolinum," Polytechnic School manufacture and supposed to hea¢ been made Length 42 ft., breadth 11 ft., depth 5 ft. 6 ins. in the war 1348. it u~as obtainedfrom Dotw at Brunswick, Professor Dr. H. Weber / The / John Reid and Co. (follows historical earliest trustmarthy information respecting Castle~ and iuut never been remm,ed from information) Otto yon Guericke's original apparatus is there till the year 1872. It is interesting from and contained in a list of the physico-chemical the fact of its having the twge escapement, 2148a. The Original Engine of Henry Bell's apparatus of the Collegium Carolinum, at which u~as used many years before the Steamboat "Comet", which mas the first t~zdulum. BrunswicL of the year 1816. In this list it is steamboat in Europe advertised for the stated that this apparatus u~s obtained from conzcyance of passengers and goods. /H.M the legacy left by Aulic Councillor Beireis, in Illustrated London News: 'If the date Commissioners of Patents. / The engine was Helmstedt. According to a special ordinance assigned to the subject of our Illustration made and fitted on board the "Comet" in of His Highness Frederich Wilhelm, Duke of 1812. be correct, it is, therefore, the oldest clock Brunswick, dated 8th October 1814, the in existence'. collection of physical, mathematical, and 23: London, Science Museum astronomical instruments acquired from the London, Science Museum (Horological inv.no. 1862-53): legacy left by Beireis, physician in ordinary, Gallery), inv. no. 1884-81. The museum at Helmstedt, u~s exhibited in the rooms, and label states 'Probably dating from 1600. [24.] "Puffing Billy*', 1813 by a later ordinance dated 9~ March 1815, There are several somewhat inconclusive incorporated within the collections of the accounts of its history before it was Catalogue p. 457: ducal Collegium C,arolinum. The air-pump removed from Dover Castle in 1872'Y 1934a. Puffing Billy, the oldest locomotive has been preserved unaltered, with the Evans (.see below) dates it 'probably engine in existence, and the first u~ich ran exception of the lever and the piston attached 16.'hqs'. with smooth wheels on smooth rails, was to it, the farmer having been replaced by a constructed in 1813 [...]. This engine worked new one of the same construction, and the Nothing is known of this clock before it until the 6~ June 1862, and mas then latter by a wooden one, in the year 1864. [...] was di~overed on the tower stairs of purchased for the Patent Museum. /H.M. But previous to this air-pump, Otto yon Dover Castle, Kent, in 1851. News of its Commissioners of Patents Guericke had constructed one more simple, existence reached Captain (later Admiral) consisting of only one cylinder and a piston, Smyth, Director of the SocieW of Anti- l.~mdon, Science Museum, inv. no. 1862- which is said to be [sic!] in the library at quaries. He went to see it together with 2. ~ Berlin (see No. 597). I...]

16 Bulletin of the Scientific Instrument Society No. 72 (2002) and lion, in what was perhaps conceived as a whi~se holdings in the twentieth century 607. Two large Magdeburg Hemispheres of process of evolution towards ever better became the foundation for ma~w Eur- copper / Pnffessor Dr. H. Weber, Brunswick / instruments? Anthtmy Turner has done opean museums of the history of science. The two large hemispheres of copper are tht~e more than anyone else to trace the history The Accademia del Cimento and the The of which Otto yon Guericke states [..] that of collecting scientific instrumentsY and Royal Institute of 'Studii Superiori' in after their exhaustion they. could not be his studies show that each of these Florence sent some sixty instruments, >eparated by the united stren~ht of l6 horses. motives played a role in the preservation, which can now be seen in the Museo di The. have a diameter I...I of nearly J/~ collecting and study of instruments. We Storia della Scienza; Leiden University Magdeburg ells, or, according to a second find this reflected in the Special Ix)an sent thirty of its treasures, which are now more exact statement, 0.67 Magdeburg ells.~ Collection. In a laterarticle l shall give a exhibits in the Museum Boerhaave; and complete list of contributors of historical the Royal Museum in gassel sent thirteen Illustrated London Neus: 'Otto yon Guer. instruments and their exhibits; here a few historical instruments, which are ranv in icke [...] constructed the first pneumatic examples must suffice. the Museum fOr Astronomie und Tech- machine which worked regularly, the nikgeschichte. But there were also im- subject of our remaining Illustration. As quotx,~d in the introduction to this portant contributions from lesser known These are Otto von Guericke's original article, the organizers wished to include collectors, such as the enigmatic His air-pump (5 ft. high); the two large instruments such as possessed historic Highness the prince Pless of Schloss Magdeburg hemispheres of copper (26 interest on account of the persons by whom, Fiirstenstein, from whose castle near in. diam.); the other two are receivers'. or the researches in ulrich, it had been Breslau in Germany (now Wroclaw in empl~.d. There was indeed a strong Poland), a large group of 18*-century Braunschweig (Brunswick), Technische personal element in the historical instru- mathematical and philosophical instru- Hochschule. ments selected ftw exhibition at South ments was sent to South Kensington. Kensington; perhaps one could even use None of these appear to have survived There are three Guericke air-pumps in the term hero worship. There were the ravages of the last World War; I shall existence.~* The oldest one, which was instruments associated with famous discuss the evidence later. Finally, I single also exhibited in South Kensingtony had men of science of the 17% 18" and early out one other contributor, the meteorol- been acquired by the Elector of Branden- I~ centuries, such as Galileo, Huygens, ogist G.J. Symons, simply because he burg in 1663 and is now in the Deutsches Newton, Priestleyand William Herschel. lived on the same Ixmdon square where Museum, Munich. The second one is in Apparatus made or used by more recent this article is being written!~ He sent the Kunstkaptivoli, Maim6, on loan from researchers like Dalton, Forbes, Faraday, both modem and old instruments 47 and Lurid University, and had been bought in Joule and Wheatstone were also pre- during the Loan Exhibition he held a Germany before 1674 by the Swedish sented with reverence. And if we take lecture on 'The measurement of rain- physician C. Heraeus. The Brunswick the term 'researches'to include explora- fall'. ~ pump can only be traced back to the tion, we may also mention here the early 18~ century, - which is still a full instruments associated with Sir Francis Originals and Imitations century further than the quoted passage Drake (even though in his case the from the catalogue! connection with the Cole compendium It is no secret that many antique scientific seems unsubstantiated) or Captain Cook, instruments that come on the market The 'Hi~orical Treasures' in Perspective who was particularly well represented in today are not quite what they seem to be. the exhibition." And what to say of the This situatkm has not arisen overnight, The 'historical treasures' singled out by instnanents used in the recent past in nor is it simply a matter of 'fake' versus the Illustrated London Neus were only the expeditions into dark Africa by the 'genuine'. These issues were addressed in tip of the iceberg. Analysis of the British explorers John Speke ~ and David a recent symposium entitled Scientific catak~gue shows that of the almost 1400 Livingstone.7`` It is likely that visitors Instruments: Originalsand Imitaticms.The private individuals and institutions both held these in awe as much as the Mensing Connection; following Gerard from the United Kingdom and from telescopes of Galileo and Newton, and L'E. Turner's example, 'imitation' was Europe who contributed to the Loan that they too qualify as 'historical',even used as an umbrella term for the whole Collection, almost one hundred sent if their date of construction lies well into spectrum of non-originals, from the well- historical instruments. And if, like the the Victorian period. intentioned copy or repn~iuction to the IllustratedLondon Neus, we would also forgery which sets out to deceive." The include such objects of technokgy or Yet, the historical contributit,xs to the creation of imitation instruments, applied scienceas early telegraphs,safety Loan Collection were not merely a whether with gca~ or evil intenthm, is lamps for miners and steam-engines, gallery of famous researchers or ex- in itself a manifestation of the growing their number would be much higher. plorers. Thus, for the 24 astrolabes interest in old instruments. So to what exhibited, virtually the only persons extent was this an issue in the Special What made instruments 'historical' in the mentioned are the makers. ~ The kn'ty- Loan Collection? Victorian age? Was it merely a matter of four 'Microscopes of historical interest', their age, and would 'antique' or 'early' which were presented separately from The 'historical treasures' selected by the instruments have been an equally valid the next group 'Microscopes by mcaiern Illustrated London Neus included some term? Or was it essential that an makers', are arranged very much as a objects, which from our modern perspec- instrument should have some association chronological-typological series, tive we might no k)nger qualib,.' as such. with historical perkins or events? How although by its very nature such a list These were the microscope and the important was the aesthetic element, the should include, as indeed it did, some thennosct~e from Florence, which were appreciation of the craftsmanship in- outstanding names, such as Antoni van exhibited with the clear suggestion that volved in its manufacture, placing the Leeuwenhoek and Pieter Lyonet, two they were directly associated with the instrument on a par with products of the 18"-century Dutch microscopistsP These great Galileo himself, but which are m~a' applied arts which were appreciated as examples could be multiplied. held to be 19'h-century copies. Another collectables such as ceramics or silver- 'suspect' from Florence, not shown in the ware? Should the instrument represent a Some of the most notable contributors of engravings, was a large conical hygro- link in the development of instrumenta- historical instruments were institutions, meter from the Accademia del Cimento,

Bulletin o/the Scientific ~t S,~-iety No. 72 (2oo2) 17 which is also a 19th-cenmry replica.¢ This suggests that not all contributors 3. During the SIS Overseas Trip to the 12. Albert van l-leklen,Catalogue of Telescopes Netherlands, l rode my hobbyhorse in a (Florence, 1999), pp 30-33. Inv. no. 2428, were as concerned with authenticity as welcome address, printed in Bulletin of the telescope attributed to Galileo, 1610-1640, we are now. Yet, it seems to me that these Scient.~icInstrument Soc/¢ty,No. 29 (19~I),pp. length 136 cm, wood, paper and copper. There were exceptions and that the enterprise 14-15. Later, I dix'ussed the Special Loan is no secure documentation bar this ascription, bears witness to a real concern for what Collection, with three illustrations,in the but during a recent mJtoration a piece of paper was original, a desire to present the catak~gue to an exhibition on the history of was round in the telescope with inscription: genuine ob/et timoin. We even find collecting scientific instruments, Her 'Dist: focal ...pied( 3 p ...' perhal~ in Galileo's evidence of a sensitivity on restoration /mbmet. Schatkonm~ mn de u~schap, 1550- hand. The use OF the word 'pied(' matead OF ethics, when Teyler Foundation in Haar- 1950 (Leiden 1994, Museum Boefhaave Mede- "braccia' suggests that it was made in Padua, lem, which sent Leyden jars from deling 251), pp. 13-14. not in Florence and cormdering Galileo's Martinus van Marum's batteries, had it career this implies a date as early as 1609-10. recorded in the catalogue that the coat- 4. Kenneth Chew and Anthony Wilson, Inv. no. 2427 telescope made by Galileo, 1610- ings of tinfoil were renewed recently, 'but Victorian Science and En~neerin~ Pi~rayed m 1630, length 98 on, wood and leather, listed in all is restored in the form in which it was the Illustrated London News (LoncGm, 19~3) is a a 1704 inventory as 'a telescope of Galileo ...'. selection OF ll0 illustra~ (mainly boxwood The ocular later went missing, the present used by Van Marurn."' And if there were engravings) published between 1842 and 1901; ocular dates [n'wn c. 1800 at the earliest. repn~l'u~tions in the exhibitit~n, these Histor#cal Treasures in the laen Collertion OF were clearly marked as such. Thus, the Scumt!fic Apparatus, South Kensington is nr. 88 Archaeok~gical Museum in Madrid sent 13. A.D.C. Simps~m, 'New~n's Telescope and See also Chrish~wr Hibbert, "/'he Illustrated the Catak~guing of the Royal Society's Repo- plaster casts of Roman liquid measures, London Neu~: S~rial Hish~. OF Victormn Britain k~uncl in Malaga, and OF an antique stone sitory', Notes and Records of the Royal Sociefyof (Lond~m, 1975). For an analysis OF the first ten London, 38 (1984),pp.187-214; esp. p. 206. sundial which had been di~overed in years, 1842-52, cf. Peter W. Sinnema, ~.amics Yecla, Alicante; the originals remained in ~ the Pictured Page, Representm~ the Nation in Spain? ~ the Illustrated London Ncus (AldershoL 1998). 14. The caption confuses 6 and 7; not corrected in the 23"* September issue. But if the number of imitatkm instru- 5. Illustratedhmdon Neus 6 May, p. 434; 13a' ments exhibited was probably low, and May, p. 458 and 463 (admission details);20,, 15. Gerard UE. Turner, Muse0 di Storla della as a rule these were marked as such, the May, p. 483 (report of the Queen's visit);3 'd Scienze. Catalogue of Microscopes (Florence, Loan Collection itself led to the creation June, p. 5,'~(ann(~alcement of startof seriesOF 1991), hrs. 4 and 5, pp. 26-31, are two almost tff new imitation instruments. In the bee evening lectures given m connection with identical microsc~es, the body turned horn pages of this Bulletin, Stuart Talbot has the Loan Collectkm of Scientific Apparatus by solid brass casting, both lacking their lenses. drawn our attentkm to the electrotype, 'a number OF scientific gentlemen'). Later -scholarshave increasingly doubted the copies made by Elkington and Co. of attribution to Galileo and dated the ob~,ct more recently; Turner suggests mid-19 ~ cen- some of the historical treasures from the 6. 17e' June, p. ~ ('thereference numbers of the differenti#o~-ts were rn(w,timperfect, and tury to¢ them, 'rather odd brass mic~'. Loan Collection," and m a later article I it was difficult to di~over any particular shall di.~'u~ this fascinating topic m articlewhich the visitorhad previously singled depth. 16. Anthony Turner, Early Scientific Instru- out in the catalogue as worthy of in~q~ection'). ments (note I), p. 95; Alfred N. Disney, Cyril Notes and Referenc~ E. Hill and Wilfred E. Watson Baker, Or~qinand 7. 16" September, p. 270; the engraving is on Development OF the Microscope (Loridon, 1928), page 26~. I. Frank Gn~enaway, A Short Htsto~. ~. the pp.102-104. Scwnce Museum (London, 1951, reprinted 8. 23'~ September, p. 2~; the engraving is on 1955), pp. 7-8; The Sc~e,ce Mu~um: the f~rst p. 34}0. 17. His published report is R Harting, 'Oude Hundred years (L~n~don, 1957), pp. 3-5; RG.W. Optiscbe Werktuigen, ttx-,geschrevenaan Za- Ander~m, 'Were Scientific Instruments in the 9. L. yon Mackensen, Die crste Sternuwrte charias Janssen, en eene ben~nnde lens van Nineteenth Century Dtfferent? ~,me Initial Europas mit dtren lnstrumcnten und Uhren. 400 Christiaan Huygens terugg~vonden', Album Consideration.~', m PR. de Clercq, ed, Nme- ]ahre Jt~st Burg( in Kas~l (Munich, 1982, second der Natuur 1867, pp. 257-288. teenth-centu~ Scwnhfic Instrument~ and ttwir edition), p. 121; idem, Die Naturu,is~nsch~- Makers Pal~s presented at the Fourth Scwntffic tliche-~'clmi,~'he Sammlungen. C,eschichte Bedcu- 18. Journal of the Royal Microscopical Society Instrument Sump~,mm. Amsterdam 23-26 (kto- tun,~ und AussteUun¢ in der Kasseler Orang~'i¢ 1889, p. 164. her 1984 (Leiden/Amsterdam, 1995), pp. 1-12, IKa~el, lb'~l), p. 10. e~p. 9-11; Anthony Turner, Early Scwntffic reads Instrument~ Europe, 1400-1800 (London, 19. The caption 'Sir Humphry Davy's 10. Ca.,rard UE. Turner, I:li:abethan lnstrunwnt first safety lamp', but the text identifies it 1,87), p. 278; ~ella V.E Butler, Scwnce and Makers. The Ong,ins ~. the London Trade in Tectmoh~y Museums (Leicester, 1992), pp. 22- correctly,and a rectificationappeared in the Precision Instrument Makm~ (Oxford, 2{1(}0), p. 23,d September (,sue. 23; RG.W. Ander~m, 'Connois~ur,~hip, Peda- 121: "This compendmm was presented by. the Right gogy or Antiquarianism? What Wen. Instru- H,,nourable Phdip Stanhope to the Ret~w~d Philip ment Doing in the Nineteenth-century Bl~sby., who tugl ntarried Stanhope's u,idowed 20. They must not be confused with the two National Collections 16 Great Bntain?', pp. stepnwther, Frances, in 178.t. B~¢,.'~. ,gate it to early Davy lamps in the Science Museum, inv. 211-225, t.'~p. 218-221, in ()r/eros and Ezs#ution his brother, Rdoert, in 1812, who presented it to 1857-208, described and illustrated in Neff d Colh'ctin¢ Scu'ntdic Instruments. Papers from Km~ Wilham IV. The Kin f gea¢ it to Gr~rnwich Cossons, ed., Makinf of the Modern World. the confi'renceheld m the Mu.~,um P~'rhaaz¢, Nm~l H~,pital m 1833, and it u~s later lent to the Milestones of Science and Techn~ (London, l~'Men. Sq,tembrr 1994, published as Journal d. NMM. The compendium tins, not infrequently, 1992), pp. 62-3. These have a different the Historu o~Colh'chons, 7 no. 2 (1995). been n~rred to as "Sir Francis Drake's dial'; provenance:, they were given to the Museum hou~w, there is no supportitL¢ evidence for this'. of Practical Geology in 1830 and were 2. Frank Greenaway, "More than 'a mere transferred in 1895 to the Science Museum. Gazing Place': the Special Loan Exhibition and ll. The caption gives 3. "Galileo's telescope' the Science Ctmierences', in RG.W. Anderson, and 4. "Galileo's secured telescope', but the 23~ 21. Reint Taton, 'Sur l'mvention de la machine J.A Bennett, W.E Rvan, eds., Makm~ Instru- September issoe corrects: 'No. 3, not No. 4, arithm~ique', Revue d'histoire des sciences et de ments Count. Es~*vs on Historu'al Scient(fic slmuld Imz¢ staod for "Galileo'ssecond telescope', ieur application XVI, 1963, pp. 139-100; the Instruments Pre.~nted to Gerard L'Estran~e Turn- with which he made his chief astronomical numbe¢ of Pascalines preserved is, according er (AIdershot, 19931, pp. 139-145. discaveries". to Taton, 'pro d'une dizaine' (p. 150).

18 Bulletin of the Scientific Instrument Society No. 72 (2002) 22. Jacques Payen, 'Les exemplai~s conse~ 35. Scme Preserved (note 29), ill. 93 and p. 45. Catalogue pp. 900-905 (historical) and pp. de la machine de Pascal',/b/dem, Pp. 161-78. IM; R.J. Law, /ames Wett and the Separate ~-915 (modem); a third seciion was 'a'ct.s- Condenser, (London, 1969); HW. Dickinson am/apparatus', pp. 915-92~. 23. D. Baxandall, revised and updated by and R. Jenkins,/ames Watt and the Steam Engine Jane Pugh, Catalogue af the Callectmns in the (London, 1927). 46. He lived at 62 C.amden Square, London. A Science Mu~eum South Kensington. Calculating plaque on the house reads: "Herepom 1868 to Machines and Instruments (London, 1975), m'. 9, 36. Items 606 and 607 are shown m an 1900 Inwl George lames Symons F.R.S.Pi,meer in pp. 4-5: 'Napier's Rods, cylindrical form, inv. engraving lacing p. 158; this engravu~ is the scient~c Uudy of rainfall Founder of the 1876-931. Presented by Messrs. Drmg and different horn the 0oe in the Illustrated i,mMon British Rainfall Organisatam. 7~,ice Pr~s~bne of Fage'; Anthony Turner, Early ScientificInstru- Neus. eke Roll Metm~o~ Socu,ty. 18~8 = lS~O'. ments (note I), pp. 166-67, illustration171. 37. Also exhibited as m. 608: Tu*o smaller MagdeburX hemispheresof brass / Professor Dr. H. 47. Catalogue, see 12~ of contributors p. Jdi. 24. A colour photo, with the Volta pile, is The historical items include 'Antique baro- published in Otto Mayr a.o., The Deutsches Weber, Brunswick/The two smiler hemisphen~ of br~s were usedfvr eapenments unth weights I...I scope', 'Two mountain barometers (old Mu,seum. C,trman Museum of Master'morEs of torms)', 'Daniell's hygrometer, formerly be- Science and Technology, Munich (London/ Ionl~g to Sir James South' and a thendolite, Munich, 19qO), p. 129. 38. A detailed study of early air-pumps, with 'extremely old, if not undue, purchased by the a list O4 extant air-pumps up to c. 1750, is Anne late by Sir James South as a rarity. In the "The 25. ian MacNeil, ed., An Encyclopaedia of the van Helden, Age of the Air-pump', original oak box'. History of Technology (London/New York, Tractrix,$ (1991), pp. 149-172. 1990), p. 714. 39. Catalogue pp. 1589:. 597 Air Pump, by. Otto 48. Conferences held in connection unth the lain Guericke, unth stand and 598 "/'u~Ma~,'burg Special loan Callectmn of Sca,ntzfic Apparatus 26. Manfrecl Wenzel, 'Die Entdeckung des hemispheres, both contributed by Professor Dr. (London, 1876. 2 vols.), 11, pp. 2S3-Z58. elektro-chemischen Telel~afen durch Samuel Lepsius, Berlin, who was Chief Librarian at the Thomas Si~e~nnmerrmg', Archly f~r deut~he Royal Library (List of pp. I - ii). Postgeschichte, vol. 2, (1987), pp. 5-25, gives contributors 49. Scient!~ic Instruments: Or~finals and Imita- details on the whereal~uts o4 the various tams (note 40L especially Gerard UE. Turner, Sommerring telegraphs. 40. Anthony Turner, Early ScientificInstru- 'An inquiry into the Imitation ~ Scientific ments (note I), 'A Note on the Collecting O4 Instruments', pp. 49-60. ScientificInstruments', pp. 275-9; idem, "From 27. Dictionary of Scientific Bmgraphy, vol. V Mathematical Practice to the History of (1972), pp. 68-9. 50. Catalogue p. 099: 'Hyxrometer, at condensa- Science. The Pattern of Collecting Scientific tam, imcnted by the Grand Duke Ferdinand il. dei pp. 135-150 in Or~fins and Instruments', Medici': Museo di Storm della Sca,n~. Catalogo 28. Mara Miniati, ed., L'Eta di Galileo. B secolo Ez~lution of Collecting ScwntiJ~c Instruments (Florence, 1991), p. 14~ Igmna, tro ~rephca~ Sec. d'oeo della Scm~za in Toscana (Florence, 1987), (note 1); idem, 'Paris, Amsterdam, London: XIX Ferro, legno, sughero, 925 ram, with p. 00, colour photo p. 6.1. The Collecting, Trade and Display of Eady illustration. ScientificInstruments, 1830-1930', pp. 23-47 in 29. E Jones, 'The Collection of Apparatus Peter de Clercq, ed., Scamt!fic In.~truments: made by Dalton, now in the Pos~e~ion of the On,reals and Imitations. The Mensmg Connec- 51. Cataloguepp. 319-20. The quote refers to Society', Mem~rs of the Manchester IJterary and tion. Pnweedin~ of a Symposium hem at the one of the I00 jars,arranged in [our cases. For Phtl~ophical S0c~ty, M (1904), pp.I-5 and C.L. Museum Boerh~n¢, Leiden, 15-16 October 1999 the I

Bulletin O4 the Scientific In~-mnent Sodety No. 72 (2002) 19

,,e. J.B. Micheli du Crest's Thermometer and The Connections with G.E Brander Sofia Talas

AIC I]lll~ All AA'IRA

Fig.2 The Aarburg Fortrt~s, when" Micheli zv,ls impri.,amed from 1749 to 17o6 tD. Meisner, E. Kie.~,r, Politisches Schatzk/istlein, Frantbrt, 1o25-1626, Ill, 2)

Fig. l lacque~ B,~rthch'my Michcli ,tu Crest. Portrait lnt Roh'rt Garddh', 1721 ¢Fon,tation cularlv well known and appreciated. In his thermometers, Micheli cht~e to use Micheli du Crest). According to Van Swinden, it was one undiluted spirit of wine, unlike Ren~ of the thermometers most currently in Antoine Ferchault de Reaumur who, in use. The University of Padua owns a thermo- 1730, in a paper on thermometers that meter of the ~'pe invented in 1741 by the met great success7, used spirit of wine The Universal Thermometer of Micheli diluted with water. It is interesting to Geneva ,scientist Jacques Bartheldmy du Crest Micheli du Crest (Fig. 1). This thermo- point out that, during Maupertuis' famous 1736 expedition to Lapland", meter is signed "Fait par G.F. BRANDER Before presenting Micheli's thermometer, Membre ,te I'Acad. des Scienc~ Eh'ct: de some of Reaumur's spirit or wine a few words should be said about the thermometers froze while mercury ther- Ba~'ii're et Mecham,'ien i~ Au~sh, urg'. In this inventor, Jacques Barth61dmv Micheli du paper, the most important features of mometers had not. As a result, many Crest) He was born in 1690 in Geneva in scientists acquired the conviction that Micheli du Crest's thermometers are an aristocratic and wealthy family and, pre~nted, and we examine the part mercury could stand lower temperatures according to family tradition he joined than spirit of wine, and this conviction played by these instruments in the the army in 1709, in a Swiss regiment h~storv of" thermometrv. The paper also persisted for many years", as the freezing serving the King of France. He left temperature of mercury was determined deals "with the relations between Micheli military service in 1738. He was always and Ge~rg Friederich Brander. Their only in 1783 by Henry Cavendish.'" As very active politically, in particular for Micheli, he rightly considered that correspondence, kept in Geneva and up against the Geneva Government, and to now unpublished,' gives us precious R6aumur's thermometers had frozen this led him to be sentenced to life because of the water they contained, details about their cta*peration on ther- imprisonment in 1747. He was arrested mometers. and argued that undiluted spirit of wine and imprisoned in the Aarburg Fortress, thermometers could stand very low near Bern (Fig. 2), where he remained temperaturesY First of all, we can ask ourselves what from 1749 to 1766. He was released only was the situation of thermometry at the three months before his death. The Lower Fixed Point of the Scale hi, inning of the eighteenth century? It was, in fact, quite confusc~ and chaotic, As for his scientific activity, Micheli To establish the thermometric scale, becau,,~ thermometers were by no means worked on the one hand on topography Micheli used two fixed points. For the comparable. This was mainly because the and cartography, and on the other on lower one, in the very first years of his scales were divided arbitrarily and thermometry. He published his first work on thermometers, from 1740 to because different thermometric sub- paper on thermometers anonymously in 1742, Micheli chose the temperature of stances were used Already in 1664, Paris in 1741 with the title 'Description the Paris Observatory cellars, which he Chri.,,tiaan Huyghens was aware of the de la meth(~e d'un Thermometre Uni- marked as the 0° of his scale. At that problem: - but no solution was found. By versel'. It was undoubtedly a success as time, the temperature of places under- the end of the centuD" several ~ientists Micheli signed all his following works on ground was considered to be constant complained about this state of affairs? the subject as the 'Auteur de la methode and several scientists, such as Robert d'un Thermometre Universel'? - By the Boyle and Edmund Halley, had sug- ~.xeral dt~igns were proposed during term 'universal' Micheli not only meant gested it as an excellent fixed point for the eighteenth century to achieve a that his thermometer could be repro- thermometers. '2 Joseph Nicolas Delisle ~,tandard thermometer, that is a reliable duced anywhere, but also that he had actually chose the Paris Ob~rvatory instrument that could be duplicated marked on it other common thermo- cellars temperature as a fixed point in anywhere. In 1778, Jan Henri van metric scales besides his own scale, so the thermometers he designed in 1724." S,;inden gave a list of more than thirty that it was possible to translate the different thermometric .scales.' Among temperature measured from one scale to in this context, Micheli's choice for the tht.~e, Micheli's thermometer was parti- another. lower fixed point would not be surpris-

20 Bulletin of the ScientificInstrument Society No. 72 (2002) The Higher Fixed Point and Micheli's Influence on the So-called R~aumur's Thermometers

Particularly interesting with regard to Micheli's contnbution to thermometry is his higher fixed [n~int. He chc~se the I~iling temperature of water and marked it 100°. Now, the idea of using this temperature as a fixed point had already been profx~l in the seventeenth cen- tury, but with spirit of wine there was a serious problem, as spirit of wine boils at a lower temperature than water. Spirit of wine thermometers simply could not stand the boiling temperature of water and scientists at that time were aware of this problem. Delisle, for instance, made in 1724 spirit of wine thermometers, but having realized how difficult it was to graduate them in boiling water, 2~ he decided to use mercury in the thermo- meters he devised in 1732. George Martine, too, in 1740 stressed the gravity of this problem in his severe criticism of spirit of wine as a thermometric liquid."

So, why did Micheli choose the boiling temperature of water to graduate his spirit of wine thermometers? He did so because he found an excellent solution to the problem, by leaving enough air at the top of the liquid column, so that when Fig.3 Drau,m£ of the earth. Different temperatures and the the spirit of wine expanded, the pressure "Temt~rF' are marked. (J.B. Micheli du Crest, "Extrait d'une lettre above the column was raised and the dcrite d la Rochelle le 7 octobre 1758", Acta Helvetica, 4 (1760), pp. boiling temperature of spirit of wine was 1-23). raLsed too. With a high enough pressure, the boiling temperature of spirit of wine became higher than the boiling tempera- ing, but on the other hand Micheli was From 1742, Micheli changed his way of ture of water outside, which the thermo- thus not following the metht~ proposed graduating his thermometers, certainly meters could thus perfectly withstand. in 1730 by R~aumur, whose fixed point not because of criticisms but because he According to Micheli, he managed to was the freezing temperature of water. had found a better fixed point, which leave enough air in the tube simply by Now, ra~t to follow Rdaumur's principles was the temperature of water in ice, avoiding heating the air at the top of the was really surprising, especially for a which he considered definitely different column when he sealed the tube. In other French-speaking scientist,because R6au- from the freezing temperature of water. '~ words, the sealing operation had to be tour was regarded as the highest author- in practice, Micheli used this new fixed done quickly, so that heating would not ity on thermometers at that time, and I~int to graduate his instruments, but he rarefy the air. z~ Of course, the idea of French scientists had an extraordinary having air at increased pressure at the respect for him" kept the 0" of his scale at the temperature of the Paris Observatory cellars. He had top of the liquid column was very good, several reasons for doing so. In particu- and it is still used nowadays in some Anyway, Micheli was certainly not a man mercury thermometers, to make them tar, he was persuaded that the tempera- cope with temperatures up to 40@' C. :4 who compromised. In his first paper, he ture of the Observatory cellars wrote that it was difficult to fix the corresponded to an internal mean tem- In 1748, Micheli's solution was adopted freezing temperature of water with perature at which the sun had brought by Noilet who used it without crediting accuracy but, in 1742, he made some the earth since its creation. Such a the Geneva scientist, though he Perfectly experiments connected with the super- temperature was thus a general term that well knew Micheli's works. :~ In fact, here cooling of water ~', and he succeeded in could be found in most underground we come to a crucial point, becau~ making water freeze at different tem- places. To confirm his idea, he went on Nollet who was, as we noted, Rdaumur's peratures below the melting point of ice. measuring for years the temperature in thermometers official maker, repeatedly He concluded that the freezing point of mines, caves, wells and cellarsY He also wrote that he was following exactly' water was not at all a convenient fixed Rdaumur's instructi(n~s, while R~aumur point and explicitly criticized R~aumur's asked friends and other scientists to make such measurements. Micheli thus had explicitly written that it was better to choice. French scientists did not accept leave as little air as possible in the tube. ~ this, so that Micheli was attacked in 1742 thought it was very important that his 0~ corresponded to this internal mean by Jean Pierre Christin, one of the The point is that in Reaumur's original inventors of the centigrade scale)" and temperature, the 'temp~r~', which he method, it was completely irrelevant then in 1748 by Jean-Antoine Nollet, in saw as a universal term (Fig. 3). From whether thermometers could ct~e with his Levons de Physique Expdrimentale. 1748, he decided to mark on his thermo- the boiling temperature of water, or not. Noilet, in particular, who was R~aumur's meters at 0 ° 'tempf, r~ du globe de la Terre' Rttaumur's scale was based on one fixed thermometers official maker) 7 was very instead of "temp~ de la cave de rObserva- point only, namely the freezing tempera- hard on Micheli. toire Roial deParis'. 2° ture of water, and the tube was then

I~lletm ~ the ~m~ ln~truun~mt Society No. 72 (2OO2) 21 divided into degrees by using as unity a imprecise and unpractical. Once more, referring to Noilet but forgetting Delisle given fraction of the volume occupied by Micheli did not follow R~aumur. Instead and Micheli, though he perfectly knew the spirit of wine at the freezing he used a short thread of mercury which and even praised Micheli's papers. temperature of water. A spirit of wine/ he moved little by little along the tube. water dilution was chosen whose boiling By marking and measuring the length of The Other Scales on Micheli's point in an open vessel corresponded to the thread of mercury in the different "Thermometer 80 ° on the scale. But R~aumur was so I~siti(nt¢ along the tube, Micheli could ambiguous in his explanations that divide the tube in equal parts by volume A noteworthy l~int in Micheli's work is people at that time underska~ that his and estimate its uniformity. He could the comparisons he carried out of the 80° corresponded to the l~iling tempera- then choose the most regular tubes (he thermal expansion of different thermo- ture of water. The so-called 'Rdaumur's selected one out of fifty), or the most metric liquids. Scientists at that time thermometers' were therefore based in regular parts of the tubes (two or three already knew that the thermal expansion practice not on ~ne but on two fixed out of fifty tubes). In some cases, the varied from one liquid to another, but ~ ints, one of which was precisely the graduation was marked on the tube Micheli was the first to compare quanti- iling point of watery proportionally to the imperfections, that tatively the thermal expansion of spiritof is to say that the degrees really corre- wine with that of mercury and of linseed As for Nolk~, he based his thermometers sponded to equal volume parts of the oil, which had been the liquid used by on one fixed i~mt, following Reaumur's tube. Usually, however, the degrees were Newton in his thermometer in 1701. original method but, as we have already simply marked at equal distances on Taking his spirit of wine thermometers mentioned, he left some air in the tubes, th~wse tubes that were regular:. Micheli as standard, he found out that, compared in order to make them withstand the engraved the thermometric scale on with spirit of wine, the expansion of boiling temperature of water. Then, he plates from which he obtained printed- mercury and of linseed oil was non chose the dilution of spirit of wine such paper scales. These paper scales were linear, it decreased as temperature in- that 80 ° corresponded to the boiling glued on wooden boxes or panels, on creased. As for the linearity of the temperature of water and not to the which the thermometers themselves were thermal expansion of spirit of wine with lx~iling temperature of spirit of wine. also fixed. ~ To choose bulbs of suitable temperature, Micheli just assumed it, but Reaumur's thermometers made by Nol- size for the selected tubes, Micheli used a he was perfectly conscious that he had let were thus completely different from correspondence table, based on his own not proved it at all?° Reaumur's first thermometers, but Nollet calculationsy and he filled the bulbs with never admitted it clearly: We may even an appropriate quantity of liquid in order it is interesting to point out that the wonder whether he underst(x~d the great to have a satisfying correspondence with experimental meth~l used by Micheli for difference he intn~luced. Anyway, he his engraved scale. his comparison was very similar to the certainly contributed to increase the method adopted by De Luc several years confusion that surrounded the so-called iateP', with the difference that De Luc The drop of mercury calibration method Reaumur's scale for many years during was of course very g~d, and it became took mercury as standard. De Luc also the eighteenth century. It is not surprising the standard calibration method in the tried to dem~mstrate the linearily of the at all that Lavoisier, ~'ho in 1776 collected nineteenth centuryY~ In fact, Micheli was thermal expansion of mercury as a thirty-eight thermometers to study the not the first scientist to prop(v~e it. That function of temperature, but his experi- temperature of that year's particularly was the Danish Ole Rt~mer in the very men~ were m~t at all reliable. Later on, in cold winter, observed that Reaumur"s first years of eighteenth century, but 1779, similar comparisons between ther- thermometers made after 1740 did not R~mer's work (m thermometers was not mometric substances were published by correspond at all to Reaumur's original published until 1910, and Micheli surely Johann Lambert, who assumed without instruments. ~ did not know it." in 1732, J.N. Delisl'e question that air was the substance that proIx~l the drops of mercury method expanded linearly with temperature.*: All Micheli got quite furious with Nollet, when he designed his mercury thermo- these experiments are very important as who had criticized him but then adopted meters. ~ However, Delisle was at that they show how scientists were looking for his ideas without acknowledgement. He time in S. Petersburg and it seems that his a rational temperature scale or, in other wrote in 174q: work on thermometers did not become words, for a thermometer whose indica- known in Europe until the summer of tions would always be proportional to the I made the first [thermometersl in Paris quantities of heat it had absorbed. in 1740 [ ...] which could stand it while it 17407 ~ As for Micbeli, he devis~l this calibration method in April 1740, thus was at the time an accepted prejudice [ Basing himself on the correspondence he independently from Delisle. ~ Anyhow, ...] that Spirit of wine could not stand the had established between the thermal having been informed by Gabriel Cramer degree of heat of boiling water. As a expansion of the three liquids, Micheli of Delisle's work, Micheli, in his 1741 consequence, Mr. l'Abb~ NOLLET could worked out a point by point correspon- paper, presented the calibration method learn ms" method about it only at that dence between his scale and other well- as his own but he fairly added 'I have just time ([ suppose in 1741.)-" known thermometric scales. He then learnt that Mr de Lisle had invented the marked those scales on his thermo- The Calibration Method same method in S. Petersburg'Y meters, so that people could easily traRslate the temperature measures from During the seventeenth century, the It is quite sad to observe that Nollet who, one scale to another, or directly read on graduations on thermometric tuh~ were as we noted, claimed that he faithfully their thermometers the temperatures in .simply marked at equal distances from followed R~aumur's method, broke once the different scales. Micheli studied and one another. Now, as the diameter of more his word because, instead of marked on his instruments the following m~t tubes was not uniform along the choosing R~aumur's calibration method, scales: R,baumur's old and new scale,*' whole length, the degrees thus marked he chose the drops of mercury calibration Hale's, Fowler's, Newton's, Delisle's, did not correspond to parts of equal meth~." He did so without any refer- Fahrenheit's, and Christin's scale,u volume, and this was of course a serious ence to Delisle nor to Micheli, who obstacle to achieving reliable thermo- complained about it in 1749Y Further- The Connections Between J.B. Micheli meters. more, a few years later, in 1772, Jean du Crest and G.E Brander Andr~ De Luc, in his famous Recherches In 1730, Reaumur proposed a method of sur ies Modificathms de I'atmosphi, re, also In working on thermon~try, Micheli du calibrating the tubes but it was quite adopted the same calibration method, Crest was both scientist and craftsman.

22 Bulletin of the Scientific Instrument Society No. 72 (2002) He always carried out his experiments wine, which he found of better quality by himself and personally made his than what could be bought k~cally. It thermometers. He had bulbs and tubes seems that by 1760 Brander was perfectly blown by a gla~maker, and then chose satisfied with the Uni~'rsal Thermometers the best tubes and selected an appro- he made as, on the 26 th of February, he priate bulb for each tube. He also wrote to Micheli, who had sent him personally coloured the spirit of wine another of his thermometers, that he and prepared the printed-paper scales found it perfectly similar to his own) ~ that he stuck on the wooden thermo- meters supports. We learn from his Brander asked Micheli for copies of all letters and manuscripts" that he made his thermometry papers which, with hundreds of thermometers. He wrote for Micheli's authorization, he had trans- instance that, at the beginning of 1744, lated into German. The translator was he had calibrated enough tubes to make J.C. Thenn, Brander's brother-in-law." 700 to 800 thermometers*~ and, accord- The German versions were published in ing to him, his method was so straight- Augsburg in 1757) ~ In 1765, a second forward that anytn~dy could easily make German edition was published, as the two or three thousand thermometers a first one was sold out and was still asked years for. ~ A third edition was published in 1770, after Micheli's death. ~: Micheli sent a very large number of his thermometers to scientists and friends This third edition is particularly interest- throughout Europe. A manuscript list of ing as it also contains a paper by Brander, the pes~ple to whom he sent his instru- rich in technical details, where Brander ments from 1741 to 1745 enumerates declares that he is making and selling more than 300 names, among them Micheli's thermometers. ~ We learn that Daniel Bernoulli, Gabriel Cramer, Willem Brander made three models of Micheli's 's Gravesande, Peter van Mus~hen- thermometers with scales of different broek, Anders Celsius, and the Academy length according to the use the thermo- of S. Petersburg." meter was intended for. One model was graduated up to 100 degrees, another Of course, Micheli's scientific activity one, for meteorology, could indicate suffered very much because of his temperatures up to 50, 60 or 70 degrees imprisonment and, though he was al- and finally, some thermometers bore Fig.4 Thermomeh,r off lowed to pursue his experiments in the large divisions, the degrees being in turn Micheli~ design made Aarburg Fortess, his researches were divided into quarters of degree, to make by. Brander, kept at the much slowed down. He was very sad very preci~ measurements. Mu.~'o di Storia della about it and, wishing that his universal thermometers could be widely known Fisica, University of Brander was really enthusiastic about Padua. and used, he was interested in finding a Micheli's thermometers about which he reliable person who would make and sell wrote: 'The invention of a Universal them. 4" Thermometer, as a sign of our more and days. There are two of them in C~rlitz, ~' more enlightened epoch, has to be which are not in g(~d conditions, and In 1754 Micheli, through J.J. Ott, one of greeted with gratitude'. ~ He added that one at the Universi~' of Padua (Fig. 4), his corresp(mdents in Zurich, had the it was because of the peculiarities of these which, quite luckily, is perfectly pre- first contacts with Georg Friederich thermometers that he had grown inter- served. An inscription at the top of the Brander (171~1783) who was already, ested in them, in spite of his being instrument (Fig. 5) gives some details: in th(~.~e years, a renowned instrument- already very busy with his '...other "Fair a~vc de I'Esprit de Vin qui enlt~wte hi maker in AugsburgT' From Ott's letters", important mechanical and physical Poudre Re~,l~ sur 100 dcgr~ depuis h' it appears that Micheli had asked ()it to works ...'~' Finall)~ as for the prize of Temper¢ du Globe de la Terre lu~tu'~ I'Eau buy for him from Brander some drawing these instruments, Brander wrote" bouilhin.e excessi1~,m.t le Therm.tre phmc,e instruments, and that Brander asked Ott /u~u'~ ce point et le Barometre a 27.t,,uc~ to send him some of Micheli's papers on ...i will keep it so low [ ...] that, firstly, 9.hgnes'. thermometers. Then from 1755, Micheli nobody will find any rea~n to complain and Brander started exchanging letters. and furthermore, everybody will see that In this instrument, everything was done They corresponded at least until 1760. my highest satisfaction consists in mak- according to Micheli's ideas. The 0° of Micheli's letters to Brander seem to have ing this instrument useful to everyone, the scale for instance corr~ponds to the disappeared, but twelve letters from and in promoting as well an expansion of 'TEMPERE' and, along the tube, we .see Brander to Micheli still exist and are kept this branch of the natural sciences. "~ the different scales that Micheli had in Geneva. ~ studied and put in correspondence with After Brander's death in 1783, C.C. his. Different temperatures of various From those letters, we can clearly see H6schel, who had become Brander's places in the world are marked (Fig. o) Micheli's interest in Brander's instru- partner from 1775, continued the work- as, for instance, the temperature of 33" ments, inparticular in surveying instru- shop. We can see from his trade below zero, measured in 1755 in Aar- ments, andBrander's interest in Micheli's catalogues that he continued to recom- burg, the fortress where Micheli was thermometers. Actually, thermometers mend and sell Micheli's universal ther- impri,~ned for years. Micheli himself became very quickly the main subject of mometers.'~ had (~viouslv communicated this tem- their correspondence, and Brander perature to Brander. Another mter~ting started making thermometers following The Universal Thermometer of Padua l~int is the temperature of 27' below Micheli's instructions. He asked Micheli University zero measured in Augsburg in 1766, for much advice, and even requested to which enables us to date the manufac- be sent a thermometer, some thermo- Micheli's universal thermometers made ture of this thermometer after 1766. On metric tubes and a sample of spirit of by Brander seem to be quite rare nowa- the other hand, we know that this

Bulletin of the Scientific h~trumeqntSociely No. 72 (2O02) 23 ° .~

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Fig.5 Brander~ stgnatun" on the thermometer tMu.q~ di Storia della Fisica, Units'rsiti: di Padova Fig.6 A detail of Micheli~ thermometer instrument, which is signed by Brander disposition me plait le plus, et le ie trouve n~ade In/ Brander. We can see the different alone, was made befl~re 1775 because d'une commoditd' sans egale pour faire scah~, that Micheli tuid studh'd. (Mu.~oo di alter this date, Brander and H(~chel des observations'."~ Storia della Fisica, Unipersitlt di Padm~) both signed the instruments made from their workshop. As fl~r the connections between Micheli Fluids by Heat and Cold', Phih~ducal Trans- and Brander, their correspondence is an actions of the Rayal S~lety, 17 (1093), pp. 650- Concluding Remarks interesting example of ct~peration be- 656; Rt~ Antoine Ferchault de Reaumur, tween an inventor and an instrument- 'R/.'gles pour construire des Thennometres Micheli's thermometric scale is often maker. In this sense, the universal d,mt It,sdegr~ soient comparables', Mr'moires mentioned as one of the first attempts thermometer kept in the University of de l'Academie Rouale des Sciences (I 7.'~}),pp. 645- towards a centigrade .~ale, but Micheli's Padua is a pr~'ious material relic of this 723. ch~e collaboration, and of Micheli's work on thermometers Ls very interest- 4. J.H. van Swinden, Dissertation sur la ing for other and much more important ideas. comparal~m des thermomHr~ (Amsterdam, rea~ams. In particular, we have ~'en that 1778). Micheli contnbuted to the progress of Acknowledgements thermometrv in various ways. He was 5. See for instance Micheli du Crest lo90-1766 one of the fir,~t scientists to pro~e the ! would like to thank Dominique Micheli, homme des Lumwres, Maitre Tavel, Gen#ve, drops of mercury calibration method, who kindly authorized me to examine which gives a partial bibli,graphy; JH. Graf, the papers of J.B. Micheli du Crest Das Leben und Wirken des Physikers und carried out the fi~t quantitative compar- Getrlaten JB. Micheli du Crest aus Gent (Bern, i,,on of the thermal expansion of deposited at the Archives d'Etat in 18'~0). ditterent liquids, and had the idea of C,eneva. ! am ai~ grateful to Jacques introducing air at the top of the liquid Barrelet, Archivist at the Archives d'Etat 6. Micheli wrote several papers signing column, in order to raise the tn~iling de Geneve. Finally, my thanks to Mrs himself as the "Auteur de la Mt',thode d'un temperature of the thermometric sub- lnge Keil, for her prt~ous suggestions Thermometre universel': 'D6termmaticm du Mance. and her careful tran~ription of Brander's plus grand froid que I'on ait 6pmuvt~ commu- letters from Gothic German to modern nement dans Paris ,~ une expositi~m du Nord, Finally, even if alm~r,t unknown nowa- German, and 1o Jean-Pierre Humi, who en 17(r4, en 1740, & le 10 janvier 1742', les ecrits 399, davs,Micheli's thermometer was one of helped me to find in Geneva various Obser~utams sur na~dernes, Lettre b~n~ks and manu.,xripts concerning Mi- 27 (1742), pp. 206-216; this article was also the mtr, t important of the eighteenth included in lournal Heh~tulue (ff.vrier 17471, cheli du Crt~t. century and, while Christin and Nollet pp. 155-165 ; 'L~,'scriptionde la m/.th,xte d'un ~'~ erelv attacked it, various other ~ien- th'rmom6tre universel', Iournal Heh~'tlque (Hn- tl~,ts appreciated it veto" much• Gabriel Notes and References vier 1747), pp. 80-112, which is an amended (.ramer, for instance, wrote in 1741 'C'est version of his original 1741 paper; "Pr¢~.'~l~du un li~re que ce rhermometre-la'.~ Jean 1. "[hiscorrt~pondence is actually in course md,me Auteur I~ur determiner la Correspon- Jallabert and Daniel Bernoulli, who both of publication in the Zeit,Hmfl des th~h,ris,'hen dance des Thennometres de Mrs. De Lisle, Verem~ isn; Schu,aben by Inge Keil and ,'~fia Fahrenheit, Newton & de plusieurs autres avec corresponded with Micheli for years, Talas. u~axt the universal thermometer fi~r their .~m Thermomi,tw d'esprit de vin', Iournal own thermometric measurements."~ Jo- 2. Chri~tiaan Huyghens, ()eurres compli,tes, Heh¢tique (ft~vrier 17471, pp. 166-174; Recueil hann Lambert considered that Micheli's edfled by the ."k~ciet6 Hollandai~, des Sciences, de dwerses pi&'es sur h~. thermomi'tres ef baro- work was very g(,'xl ~ and, in 1741, 22 vols, La Hague, 1888-19~). m,'tn'~ (La Have, 17%1, which contains the V';illem's (;rav~,'~ande wrote to Micheli previously pul~lished articles and a °Memoire 3. See Edmund Halh, y, "An Account of instructif sur It's Thermomt,tres de Mr. de that "De tous h.'s ihermometrt~ que ~e Several Experiments made to examine the Reaumur & sur ceux de I'Auteur, fait tna forme connois I ..-1 le votre tst celui dont ia Natuw of the Expansion and Contraction of de Lettre pour s~,rvirde rephrase au 4me Tome

24 Bulh,tin of the £-icntific Instrun~.,nt ~riety No. 72 (21)02) des Lecom de Physique de Mr. l'Ab~ Nollet' 21. Joseph Nicolas Deslisle,'C~ervatiom du 43. Micheli personally carried out experi- which is dated j~nuary 1749; 'Recueil de Faites pendant Its grands ments with different models of ongiMI R@- divetses pi~es sur It,s therm~ e~ baro. de la Sibttrle', Mimoires de l'Aca&bnieR o~le des aumur's thermometers, that he defined as 'old' mt~es', Acta Heh,efica, 3 (1758), pp. 23-96, Sc/encesde Paris (1749),pp. I-9. 'new' R/taumur's ~. which contains the same articles as the Recutil publi.,d~ed in 1756; 'Extraitd'une iettm 6n'ite 22. George Mart(he, 'Essay on the construc- 44. For a stanmary descnption of these scales, la Rochelle le 7 octobre 17~', Acta Heh,ef~, 4 tion and graduation of themmmeters', see Van Swinden, of. cd., and Middleton, 0p. cir. (1760), pp. 1-23. Medical and Philosophical (London, 1740). 23. The sesling operation was carried out at a 4~. AEG, Archives Privttes, Ms ill. 7. R~umur, 'R6gles',op. cir. The ~ of given pressure of 27 inch~ and 9 lines. See this paper was probably due to RtSaumur's 46. BPU de Genth,e, Ms 214,8, M~hode, op. c#t. Michdi, 'Desmptinn', 1747, op. dr. personal prestige and authority.As a matter of 47. AEG, Archives Privttes, Ms 111.721, letter fact, the scale proposed by R~umur, based on 24. J. Thewlis, Encyclopaedic Diction,~ry of Michel( to P~ Bt;raud (31"* January 1752), op. one fixed point, was similar to the one P hys/cs (Pergamon Press, 1962). c~. published by Robert Hooke in 1665, see Robert Hooke, Micrographi~ (London, 1665), which 25. Nollet,op. all. 48. AEG, Amhives PrivY.s, M~ 111.939. did not attract much attention at that time and 26. Ren~ Antoine Ferchault de R,~aumur, 49. AEG, Archives Privt~es, Ms 111.721, letter was very soon forgotten. The so called 'Second m~moire sur ia construction des Michel( to Ptre Ik~raud (31" January 1752), 0p. 'Rttaumur's thernu3mete~', which remained I~mnomt~, dont les degrtSs sont compar- popular well into the nineteenth century, were ables', M#moires de I'Acad#mie goyale des 50. Alto ~rac.hner,ef a/., G. f. Brander 1713- in fact very different from R#aumur's ori[~nal Sc/ences de Paris (1731), pp. 250-296. instnmwnts. 1783 (Munich: Deutsches Museum, 1783). 27. Such ~ wene still in me wall 51. AEG, Archives Privt~s,Ms III. 8. EL. Moreau de Maupertuis, 'La figure de into the nineteenth century in France and b Ter~ determm~e par Messieurs de I'Acad& surrounding countries, even though the 52. AEG, Archives Privctes,MS, III. mie Royale des Sciences Qui ont mesu~ ie French Gov~ chose, in 1794, the centi- 53. AEG,/m-hives Priv~s, MS 111.360. Deg~ du MtSridien au Cercle Polaire', Mhn- grade scale as the offncial ~ scale. oires de I'Acadimie Ro~le des Sciences de Paris 54. AEG, Archives Privttes,Ms 111.354, (1737), pp. 389-469. 28. A.-L Lavoisier, "Observatiom sur le Brander to Michel( (22~ June 1757). de I'ann~e 1776', Papiers mixtes de I'Acadbnie 9. See for instance Jean Andr~ De Luc, Royale des Scwnces de Paris, Session 17 avril 55. Jacques Barth~l~my Michel( du Crest, Recherches sue Its mod~cations de l'atmosphi~ 1776, quoted by W.E. Knowles Middleton, A Sammlung tiniger Idtinen Schriflen yon deln (1772). History of the Thermometer and its Use m ~ern und ~ncmetern dunS den Ver/as- Mefe~/o~ (Bal~, 1966), p. 119. sty der Mefhode tines Univer~l-71wrnawnefees I0. Henry Cavendish, 'Observations on Mr. (Augsburg, 1757). Hutchim's Experiments for determining the 29. Micheli, 'Recueil', 1758, p. 85 56. J.B. Michel( du Crest, M/ckad du Crest Degree of Cold at which Quicksilver ffezes', Mtine Schriflen vofl den Thernwn~ern und PhilosophlcM Transactionsof the Royal Society, 73 30. Biblioth~que Publique et Universitaire (1783), pp. 303-328. (BPU) de Gen~e, Ms 214~, M~thode pour Bmometern (Augs~ 176,q). construiw des thermom~res d'esprifde vin sur 57. J.B. Midwli du Crest, K/eme .Schr~f~mvow 11. Michdi, 'Recueil', 1758. des planches~, and MS 214,7, Instructions den Yhemm~ern and ~'0metern ( Augsburg, pour construi~edes therntom~resa espritde vm 1770). 12. See Halley, 'An Account', op. cit.;George sur un~ planche gr~W d'un pied de grandeur ef Marline, Ess~issur la constructamef com~raison pour It,s retablir sur toute sorte de planches 58. G.F. Brander, 'Nachricht yon dem Urd- des thermonwfres(Paris, 1751); Edn~ Mariotte, /ors~'//s sont c~sres, h.mdwnttm papers by versaithennome~', m Micheli, Kleme Sch~'- du chaud ef du froid (Paris,1679). Jacques Baby Michel( du Crest. L~n, op. nt., pp. 215-227. 13. Joseph Nicolas Delisle, '~atiom de 31. Archives d'Etat de Gen~e (AEG), Ar- 59. Brander, ~. c/f., p. 218. l'~clipse totale du soleil du 22 mai 1724', chives priv6es, Ms 111.721, letterMidwli to 60. Brander, q~. cir., p. 220. M~/res de I'Aca&bn~ R.o~ie des Sciences de Pt~ Bth-aud (31" January 1752). Paris (1724), pp. 316-319. 61. Brander,op. cir.,p. 225. 32. See tor instance Adolphe C,ar~, Trattato 14. See Jean Pierre Chns~, 'C~ervatiom ~ur elenwnta~ di fuica spmn~ntale ed a~iicata e di 62. Brachner, op. ctt. la M~thode d'un thermom~tre universel', mefmm~/a, ~ Italian ed. (Milan, 18~). 63. Stidtisdwn Kunstsammhmgen, Goditz. Journal de Trf,~ux (h,v. 1743), pp. 197-222; Jean Antoine Nollet, Lq'ons de ph.vs~que exp~imen- 3.3. Ole garners Ad~rs~ria (Copenhagen, 64. AEG, Archives Pnvees, Ms 111.366, letter t~h,, 6 vols (Paris,1743-48). 1910). Cramer to Michel( (25e' August 1741). 65. BPU de C_,en~e, Ms SH 243, k,ui[les 26-27, 15. The supercooling of water had been 34. Joseph Nicolas De[isle, 'Excerptum ex Litteris Cel. Dn. de L'Isle',Misce//am.~ Berdi- letter Daniel Bernoulli to Jean ~llabert (5s' discovered by Fahrenheit in 1724, but it seems March 1744). that scientists were not fully aware of this hens/a,4 (1734),pp. 343-349;'Extract of a phenomenon in the years that folk~wed. L'abbtt from Mr. Job. Nic. De ['Isle',Philosophical 66. Lambert, 0p. c~. Nollet for instance, in 1748, still consides~ the Transactionsof the Royal Society,3~ (1736), pp. 221-229; Mbno/ws pour serv/r a I'h~oire et ~u 67. - 'Of all the themmnwtets I know [ ...] h~ezmg temperature of water as a fixed point yours is the one I prefer, and I find it of a ram perfectly equivalent, without precautions to be progrts de rastronomie, de la ~f,oRraphie ef de 1,, ph~ap.~e (St. Petersix~rg. 1738). convemence for observations'; Michel( quotes taken, to the melting point of ice. the letter he received ~ "s Grsvesande in 16. Christin, 'Observations', ~. cit. 35. AEG, Archives privt~es, Ms 111.363, letter 'Eclaircis~,~mwns ...', BPU de Gen~e, Ms Cramer to Michel( (3'~ of october 1740). Saussure 214, cited. I have not traced the 17. See Renc~ Antoine Ferchauh de RtSaumur, twiginal letterwnttert by's Gravesande on the 'Observations du thermomb~ pendant i'an- 36. AEG, Archives privttes,MS 111.364,letter Michel( to G. Cramer (12'~ of november 1740). 13~' t"ktol~er 1741. The thennonwter sent by ntse 1739 faites & Paris et en di~ts pays', Michel( to'sGravesande is now in the Museum Mt,moires de I'Acadbnie R oyale des Saences de 37. Michel(,Descr¢t/m (1741). BoeHutave, Leiden ,see P. de Clercq, The Lndrn Paris (1739), pp. 447-466. Cabinet of Ph~ws (Leiden, 19c17). 38. Nollet,ap. cit. 18. Micheli, 'Description', 1747; 'Recueil', Author's address: 1758. 39. Michefi,'Recueil', op. cir. Cmtm Interdipartimentale 40. Michefi,'Extrait d'une k.ttw',~. cir. di gicerca in St,wia e Filos~aa. 19. See Micheli's correspondence at Archives della Scienza d'Etat de Gen~e (AEG), Archives privttes, Ms 41. De Luc, 0p. cir. 111. Unitwsiti~ di Pad,,t,a 42. Johann Lambert, Pyromrtrie ader yore Via ]appelli, 1 20. Mid,i, '~', 17S8, p. 78. Mmse des F~rs ~nd der W~Vm (ik-dm, 1779). 35121 Padua, Italy

Bulletin of the Scientific lmtrummt Society No. 72 (2002) 25 The Dipleidoscope Uncovered

Paul Zoiler

and ,elf

26 Bulletin of the Scientific lrmtrument Society No. 72 (2002) I t u , ~ w .J .0

......

B l,// • - . Fig.1 Wrong explanation of the operation of ~ the diplei&~cope in Dent's booklets through the fifth edition (1850).:

Fig.2 Correctbut incomplete explanation of the operation of the dipleidoscopefrom the 1875 booklet by. E. Dent & Co/ Edition' of 1875, and 'country Mansions' had been added to the list of places that should own a dipleidoscope. However, a (actually a single reflection from each of The Mathematics of the Dipleidoscope more complicated model with telescope the two mirrors). These images coincide and adjustment for obtaining time fixes in a properly positioned instrument at times different from noon (.see below) The questions ! would like to answer a~.. when the sun is in the meridian. sold for £7 in 18672 a) What is the proper or best positioning The proper positioning of the dipleido- of the prismatic mirrors/cover glass The basic idea is well expressed in scope in space (setting it 'to the meridian' assembly relativeto the horizon and the Bloxam's patent*: in Dent's terminology) was a bit of a meridian? Is their anything magical mystery to me and apparently others as about the 60° angle between the mirrors And ! would here state, that the Invention well. Neither Bloxam nor Dent give a invariably found in commercial dipleido- cCmsists of so combining three reflecting technical description or justificationfor sc~,es? are used planes that they as ~me singleand the orientationof the dipleidoscope. Dent one double reflector, and in such a manner that an -observer may see two images of a simply gives instructionson how to set it b) Why can a dipleidoscope be used at distant object, when that ob~ct is near to an up, providing an aid to the placement in different times of the year and diffenmt imaginary plane, passing through the in- some cases with a fullor trough compass latitudes without any adjustments? Are strument, and by coincidence of those (see below) or even sending 'a competent there limits to this? images the observer may know when the person, furnished with a cheerer, to distantobject is in that imaginary plane. fix the instrument, on payment of the The altitude of the noon sun depends on actual travel expenses, and a remunera- both the latitude and the time of year. The basic commercial diplei&r.~cope con- tion to the party of ten shillingsper day." The incidence of the noon sun can thus sists of two plane mirrors attached by Dent does not reveal whether this charge not possibly always be in a plane at 90' brackets to a front plate so as to form an was also payable for the days when the degrees to the intersection of the mirrors included angle of 60" and a transparent competent person was waiting in the pub in a fixed dipleidoscope. But this is the glass cover ai~ making an angle of 60' for the noon sun to finally make an geometry assumed in all old'" and with each mirror, i will refer to this as the appearance. modem': explanations of its working 'prismatic' arrangement, which is never (see Figs. 1 and 2). To be sure, Bloxam" to be taken to mean that an actual solid Dent's explanation of how the coinci- states flatly, but without explanation, that glass prism is present. I do not think dence between the images comes about is the time of coincidence is independent of there were ever any Dent dipleidoscopes totally inadequate, really wrong, perhaps latitude and time of year. Dent' claims using solid prisms, although they could because it was 'designed for popular the same only within (unspecified) limits. have been used. As we will see, the 60" use. '7 Up to the fifth editi(m (18~) the He recommends a different geomet~' for angle is to some extent an arbitrary diagram in Fig.l was used to explain the very high or very low latitudes, such as choice and perhaps chosen because it is operation, showing a sun which does not India, while the standard arrangement easy to lay out and machine, and because change its angle with respect to the was thought to be 'sufficient for all it leads to a very simple orientation of the dipleidtwocope,but rather rays translating England and most parts of Europe." l prismatic arrangement during use. When parallel to themselves. The 'New Edition' will comment on where this limitation this prismatic assembly is placed cor- of 1875 shows the more correct (but still comes from, and how dipleidoscopes rectly with respect to the meridian and incomplete) interpretation(Fig. 2) with a optimized for different latitude bands the horizontal planes, two images of the turning dipleidt~cope: 'the rotation of differ from each other. sun" are seen close to local noon: one the earth performs this twisting opera- reflected from the front transparent glass tion for us.' Lerebours and Secretan in Let us con.sider a prismatic arrangement and the second resulting from the Paris in their 1845 brochure" repeat the o/two mirrors (MI and M2), making an internal 'double reflection' of the incident erroneous explanation of the early Dent angle 20 with each other, and a clear ray passing through the front glass brochures. cover glass iF) placed symmetrically with

Bulletin of the Scientif~ ~t Society No. 72 (2002) 27 axes, this condition is met for all incoming rays in a plane Q that is parallel to the intersection of the two mirrors and makes an angle 20 with the front face of the prismatic assembly. Any ray parallel to the Q plane, no matter what its angle a, with the z direction is, will produce two parallel rays after the single reflec- tion from the front face and the internal double reflection. It may be noted in pagsing that the angle 20 need no4 be 60", but if it is, plane Q will be parallel to the mirror MI. When the plane Q is parallel to the meridian, the coincidence of images will occur at local n~xm, indepen- dent of the altitude of the nlx~n sun, i.e. independent of the latitude and the time of year. With the normal dipleidoscope angle of 20 = 60 ° this means that mirror Fig.3 plane MI is in the meridian plane, a matic arranxement of ta~ mir- particularly easy to visualize situation. n~ ~M! and M2) and a cozcr The demonstrated independence of noon Fig.4 A prismatic dipleidc~'ope with 20 = X/ass Ill, with an mc/dent ray (i) altitude notwithstanding, coincidence 6~' pr~a'rl.v positioned to lead to coincidence characten:ed ~ its anxies rela- sometimes cannot be d~,erved simple of the solar imaxes at noon. the to a c~a,rdinate s.wstem. A ra.~ because the mirrors are not infinitely enterin¢ parallel to the plane Q large. Their limited size can prevent a will result in singly and doubly ray fTom being reflected internally simply We will next deal with the mathematics r.dlected ra~ that are parallel to because it does not intercept the mirrors. the proper placing of the dipleido- each other. It is therefore essential to raise the front scope prismatic assembly in space, i.e. plane to something like the latitude of the relative to the observer's horizon. We place of td~se~ati(m (+/- a few degrees) have already deduced that the plane Q respect to these two mirrors, thus making in order that the n~x~n rays come in as parallel to the intersection of the mirrors an angle of 90' - 0 with each of them close as possible to a plane perpendicular and making an angle of 20 with the hxmt (Fig. 3). We will use a right-handed to the intersection of the two mirrors, face must be in the meridian, and that the rectangular cta~rdinate system with an giving them the best chance to actually front plane is raised in some way to get x-axis in the ~nt hce and perpendicular hit the two intemal mirrors. Actually it is operability over a substantial range of to the intersection of the two mirrors, a even better to raise the intersection of the latitudes and for all times of the year. The y-axis perpendicular to the fnmt face and two mirror planes to about the middle of plane of the ~mt glass can conveniently pointing towards the intersection of the the band of latitudes in which the be characterized in one o4~ two equivalent two mirrors, and a z-axis parallel to instrument is to be used, which is the ways: by the angle ~b that it makes with direction of the intersection of the only option for dipleidoscopes to be used the horizontal plane, or the angle ¥ that mirrors. Let an incident ray 'i' come into at very low latitudes (see below). the intersection of the two mirror planes the front face making angles a,, a, and ~, makes with the horizontal plane (Fig. 4). with the ctx~rdinate axes. Fairly tedious These two angles are not the ,same. Dent in passing we might just note that the mathematical techniques allow as to find apparently set ~ to about the latitude of above equation (1) of course contains the the angles this ray forms with the axes the place of obse~ation, and Secretan special case of rays entering in a plane after reflection from the front face and .perhaps set "t to about the latitude, which perpendicular to the z-axis (a, = 0), i.e. after reflt~-tion from the two internal is really the more universally correct perpendicular to the intersection of the mirrors. The question is then: under what method (see table below). conditions are the ray directly reflected two mirror planes. Again, this is the h'om the front face ancl the ray exiting the special case considered in the explana- front face after a double reflection tions of the dipleidoscope by Dent, 7 parallel to each other? Parallelism is Lerebours & Secretan" and Aked. 'z The in the following we will only consider neces~ry and sufficient. Parallel rays angle a~ is now equal to the angle of dipleidoscopes with a prismatic angle of will focus at the same place in a incidence go on the front hce as normally 20 = 60". For these we calculated that telescope, thus pn~ucing coincidence, defined in optics, and a, = 9(~' + :~ The when the mirror plane MI is vertical (as and, if no telescope is used, a slight coincidence condition is now simply ¢ = it will be when it is in the meridian), 7 movement of the head lets one select 90" - 20 or go = 30" for 20 = 60". and ~b are related by: from the bundle of parallel rays sent out by the sun to obtain actual coincidence. It turns out that the condition is exceed- 7(meas.) q~calc.) ~meas.) x(ca]c.) x(meas.) ~(calc.) ~meas.) inglv simple" Dent (standard) 46" 53.0° 53" 115.7" 117~' 38.7~ ,~* (1) cos :~,/cos ~, = - cl~20)/sin(20) = Secretan 47" 54.1~' 55" 115.(}" 116" 38.3" 39' - tan(90" - 2O) Dent (India) 20" 35.5" 34" 144.O" 145° 59.4" 61"

Bearing in mind the meaning of the °'* na~t measurable with any precision.Other measured angles are +/- I to 2", and all direction cosines (cos ~, and cos ~,) as cak'ulated angles are derived from the measured 7, and will thus be affected with similar pr~ctiorLs of a unit vector parallel to the uncertainties. direction of the incoming ray onto the

28 Bulletinof the Scienh~ Instrument Society No. 72 (20[)2) the mirror planes that is adjusted nearly to the latitude instead.

Setting the angle 4~ or y while maintain- ing the mirror M1 vertical requires that the intersections of the mimns with the front glass make a certain angle X with line g (Fig. 4), which is the intersection of the front (cover glass) plane with the horizontal plane. Line g is a line which can sometimes be identified on a dipleid- oscope (see below). We find

(3) X = 90° + arcsin(0.5774/tan ~) or X -- 90' + arctan(0.5/tan ¥)

Finally we have also calculated the angle that line g must make with the east direction in the horizontal:

(4) cos ~ = 0.8664 cos(x - 90')

with X taken from equation (3) based on a hr choice of either ~ or y. Fig.5 A Dent dipleidoscope (before 1851) u~ith trough compass and We have measured and calcubted these single bubble iet¢! showing pr~a,r orientation. Base plate is 107xll! angles ~m two dipleidoscopes in the ram: atcrall about 75 mm high. Signed on corer (not shown) "E.I. author's collection one by Dent (Fig. 5), DENT'S~PATENT~MERIDIAN INSTRUMENT~82 Strand~&33 the other by Secretan (Fig. 6), both for Cockspur St.~LONDON'. English/European latitudes, and a sec- ond Dent, marked 'INDIA" (Fig. 7), kindly loaned to me for inspection by Fred Sawyer. For all three the angle j between the mirrors was assumed to be 60". Please see table above.

Everything seems to be in order, especially in view of the difficulty of measuring the angles accurately. One could probably argue that Dent set the angle ~ between the front plane and the horizontal in his standard instrument to a typical latitude for England, 53 ° corresponding closely to an average between Plymouth and Edin- burgh. Secretan might have operated by setting the angle y to a typical latitudefor central France (at 47"; Paris being about 48 '~ 50'). Note that the Dent 'India' dipleidoscope differs from the m~rthern Eun~ean ones by a smaller angle y {or smaller ~b),with Y (and not ~b) now clearh,, ,~f X set to an average latitude for the place ~;f use The latitudes of Bombay or Calcutta are both within k,'ssthan 3" of 20'. Note the Fig.6 Properly placed French Secretan Dipleidoscope (after 185,5), much largerangle g needed for the 'India' signed Secretan d Paris. Sub-ba~ is 130x140 ram; ot~rall heicht instrument to bring the mirror MI into the about 110 mm. Worm screw fine adjustment for azimuth; hinged ba~ vertical plane. for horizontal setting. A Demonstration DipleidoKope

(2) cos ~b = 0.8660 cos "t with increasing 7, and settmg either # or It is unlikely that Dent or Bloxam (a i.e. ~b = arccos(0.8660cos 7) or y to the approximate latitude will do. barrister) t~a~k this mathematical ap- y = arccos(l.1547cos ~) However, equation (1) limits the angle proach to their design. After all, they to a value larger than 30'. For values of q~ spent £600 and two years to come up (the numerical factors being lower than 30' the plane M1 can no with the final arrangement, much of which must have been spent on clmcept, trigonometric functions of 0 = 30") longer be made vertical. Therefore, if a design and testing, rather than on standard (60') dipleidoscope is to be used manufactunng pmbh, ms. The manufac- For "t above 40' the differencebetween ~b at low latitudes (certainly below 30", such ture of dipleidoscopes does not seem to and y amounts at most to 8", decreasing as India) it should be the intersection of present any special difficulties,especially

Bulk.tin of the .Scientific Instrument .c,ociety No. 72 (2002) 2q after Hadley took out a patent for his reflecting quadrant. This theorem is explicitly demonstrated in the Lerebours and Secretan brochure," and this is just about the only addition they made to the Dent booklet. This little mathematical excursion is no doubt the work of Secretan, a mathematician by training. The generalization of this behavior to E" rays coming in with a component parallel to the intersection of the mirrors is far from obvious. It seems likely that Dent established this more general case experi- mentally on a prototype incorporating an ~9 adjustment to the angle of elevation of the front plane, and the direction of the mirror planes. Using a distant light source, such as a light from a magic lantern, or a pinhole in a shade, or even just a vertical thread or line on a wall, he $ would quickly have found how the mirror plane needed to be placed with respect to the incoming light, and that the iv coincidence condition was independent of the elevation of the incident light for a Fig.7 t~'nt dq,leid,~ope (~fi,re 1851) SLc,ned ,,n c,nw (not sh,,wnl properly placed mirror assembly. Any "E.l. DENT'S/PATENT~MERIDIAN INSTRUMENT~82 Strand/ adjustments for the altitude of the nt~n &33 C,~'ksl,ur St.~LONDON. Further marked on h~lv INDIA, and sun were thus found to be unnecessary, a E.I. DE,VT/PATENTEE/504". Size 75x50 ram; tncrall about 70 mm very useful feature of the dipleidoscope.

I have recreated this process by building my own universal experimental dipleido- scope (Fig. 8) with all the adjustable features mentioned above and also an adjustable angle between the mirrors, it can also be rotated in the horizontal plane on a machinist's dividing head. My sun was normally a small laser. This is not as satisfactory as the real sun, as the edges of a laser beam are very fuzzy, and coin- cidence cannot be observed as accurately as with the sun. However, the assembly can also be used with other light sources, such as a pro~ctor with a slide containing a mall aperture, or outside, with the real sun. Extensive work with this experi- mental arrangement very quickly led to the right ideas about the functioning of a dipleidoscope, and confirmed the mathe- matics summarized above in some detail.

The Practice of the Dipleidoscope

We have presented the results of the mathematical analysis simply because some of the geometrical requirements established can be checked on examples of dipleid(yscopes (.see table, above). For the use of dipleidoscopes by country Fig.8 Liras'or>,~1 ,~,tl~,,tal,le dipleid,,>~ ,,p,' l,mlt.ti,r tht~ study, sh,,i,'n gentlemen or parsons this knowledge without h~,q'r mutation sun. was not required. A n(~m dipleidoscope was hopefully manufactured by Dent with all the proper angles when pur- for a chronometer maker. Dent only opening angle ~ in a plane perpendicular chased, and aJl the user had to do was to .,~,med to have some trouble obtaining to the intersection of the mirrors leaves 'orient it to the meridian.' It is likely that the nect.~, high quality glass, at least the mirrors alter double reflectinn at an most users did not know what that at a price he liked." For their prismatic angle 2q~ with respect to the incoming meant, and they did not need to know: dL,~ign it is likeh" that they started out ray. This law is, after all, the basis for they simply followed Dent's step-by-step with the well known thee,rein that a ray octants and sextants, instruments surely 'how to' instructions. Dent suggests of light entering an angled mirror with well known to Dent more than 100 years several methl~ls to set up a dipleido-

-'~) Bulletin of the ~ienhfic Instrument Society No. 72 (2002) scope. The most precise method, and this method the accuracy was much Types of Dipleidoecopes really the only one to yield an accuracy of reduced, and the instrument was now a few seconds in the end, was to place it perhaps not more accurate than a good The basic prismatic arrangement found in on a perfectly horizontal plane (making sundial (see below). all Dent dipleidoscopes was mounted in a the mirror MI vertical if Dent had done variety of housings, sometimes sur- his shop work properly) and to turn it The moment of coincidence can be rounded by auxiliary amenities, such as until the two suns coincided at local noon observed quite precisely because the bubble (spirit)levels, adjustment screws, determined as by a chronometer. Accu- images of the sun move with double compasses, telescopes, etc. Several of rate time was required only for this one- speed with respect to each other, and these variants are described in Dent's operation. In the 1875 edition of the time because the edges of the reflectionsof the booklets or are found in public and instruction tx~oklet 7 it is suggested for the sun are exceedingly well defined. The private collections. Their dating can be first time that the time could be obtained telescope sometimes found on dipleido- aided by the date of the editions of the fi~m the railway station: scopes aids in the observations. Dent7 booklet in which they are shown, but also recommended taking three time read- by the addresses often given for Dent's Greenwich time is telegraphed to nearly ings: the first when the two images of the places of business on the instruments every railway station at least once a week, sun just touch, the second when the themselves)* The address is usually and should the observer have no other images coincide, and the third when they engraved on the removable push-fitcover means of determining it, he had better a~ertain upon what day the time is just loose ccmtact. On the average the placed over the front mirror,and as such is telegraphed - have all his arrangements three times are each about one minute not permanently married to a particular for setting ready beforehand,and prta:eedat and some seconds apart, and each can be instrument, as the covers seem to be once from the railway station to the detected to a few seconds. Overall it mostly of a standard size. Incidentally, instrument, so that his watch may have as seems possible that the true time of many are signed 'E.I. Dent', rather than little time for variation as peasible. coincidence can be found within a few the correct E.J.,for Edward John. The first seconds. This was confirmed by my own dipleidoscopes must have been sold in Once the position was fixed (and we experiments, after some practice, to be 1843, the date of Bloxam's patent and its know that the mirror M1 now was in the sure. Dent's claim to an accuracy of a assigmnent to Dent and the first edition of meridian), the instrument was cemented fraction of second: is a shameless ex- Dent's explanatory booklet. The produc- in place. Later Dent supplied a plate with aggeration, perhaps based on the mi~ tion certainly extended into the late 1870s, a guide bar on one side. Only the plate taken notion (still popular among perhaps later.Some instruments (but no4 itself was cemented in place, and the engineering students) that a number all) exhibit a punched or scratched dipleidoscope was simply placed against representing the mean of three observa- number. On surviving examples these the guide bar whenever it was to be used. tions gets more accurate the longer one numbers range from the low hundreds The setting of the scope to the horizontal divides the sum by three. Beyond purely to the low 2~, with numbers above plane could be checked with levels, but observational (essentially random) un- 1600 normally .scratched into the base Dent also suggests using a long string certaintiesthere could also be systematic rather than punched. If only the punched hung with a weight several feet away errors, such as the mirror MI not numbers are true serialnumbers, it is not from the instrument and observing its pedectly perpendicular to the base, or ton much of stretch to suggest that the double image. This string effectively the mirror angle not exactly 60", or the total production of dipleidoscopes was offered different altitudes to the dipleido- mirrors mounted such that their intersec- about 1600 to 1700, or somewhat more scope. When the two images were tion was not exactly parallel to the front than two thousand if the scratched parallel to each other, or could be made face. Such derangements could develop numbers are also serial numbers. There to coincide accurately,the mirror MI was in use, as inspection of the internals of must he uncertainty,regarding the mean- indeed vertical, even if the base of the two dipleid

°~ Bulletin of the Scientific Instrun~ntSociety No. 72 (2002) 31 ! Platt vln

a

Fig.10. "Libra~. ' fi,rm ~. dipleidoscope, made fro,n 1843.:

'all the usual meridian and vertical baffled me for a while (especially since adjustments.'" This vertical plate is we have E deviations in Boulder). A Fig.9 Oriqinal fi,rnt =?t Dcnt'~ dlt,leid=~'ope mounted to a horizontal base. A telesc(~e single bubble level is oriented in the E-W shown m Bh,xam's patent~ and all editions of provides greater ¢~'~-,ervational precision. direction, i.e. at 717' to the trough compass the de~'ril,ti~,e h~klet." Here if is shown cemented in place outd,~,rs. It is beliez~,d that This mount is very similar to that shown box. This is quite clever, as this is all that the ant is uot required for proper functk,nm£. for the 'stepped mirror' dipleidt~scope of is needed to make the mirror plane M1 the patent. ~ A later variant of this is the vertical by means of the single adjustable instrument called the 'mural, ~'~ which 'in foot. To confound the "observer further open air; for as bv the workmanship it is point of accuracy is superior to any other." the mirror assembly is housed in a imperviot.LS to the weather, tim instrument it was first shown in the 1875 pamphlet conical housing, again not revealing any pmtecti~m than the needs no further brass (Fig. IlL: It differs from the library model covenng with which it is supplied. ~ principal directions. This type of housing by having a iockable cover of 'zinc' as it was likely ch(~Jen to save weight. This was intended to be fixed out of doors complete instrument in its substantial Deteriorated outd(~r instruments that permanently, it has the same adjusting mahogany travelling case weighs about had been cemented into place were not screws as the 'library' model, but the 1,080 g, compared to the 'India' scroll likely to be saved after they had outlived telescope is now fixed to the dipleido- based model (Fig. 7) which all by itself their usefulness. As a consequence they scope body, a further improvement over weighs 690 g. Although this instrument are now quite rare?: In the 1875 booklet mounting it on the base plate, as it was in could be set up quickly for moderate this pattern is still on the cover, but the library model. accuracy with the compass, it could, of shown placed (~rt a base with a guide bar course, also be set to the meridian with in the N-S direction (marked "EAST'), We have already mentioned that some the chronometer method, thus providing which was permanently fixed in place, the highest accuracy achievable. rather than the dipleidoscope itself. dipleidoscopes were mounted on base 'When the instrument is to be used, it plates featuring spirit (bubble) levels and has merely to be brought out and placed a full or trough compass as an aid to Shown for the first time in the 1875 against the bar. '~ quickly setting it up when travelling. ! booklet is a dipleidoscope for taking time must emphasize again that orienting an fixes at various times during the day when instrument by the compass method A variant of this instrument has the 'great accuracy is not required" (Fig. 12). reduces its accuracy considerably. The prismatic arrangement based on a 'scroll To achieve this, the prismatic assembly compasses could really not be read to base. '~' This arrangement (Fig. 7) is not was made rotatable about the intersection better than V2" and there was always a depicted in Dent's b~,klets at all, and of the two mirrors, and the time to which remaining uncertainty in the value of the was probably originally developed for the scope was set could be read on an hour k,cal magnetic variation. There is an error low latitudes. If one tried to make the scale, usually marked ~m 9 a.m. to 3 of two minutes in the noontime observa- ~'pe in Fig. 9 for low latitudes it would p.m. in 5 minute intervals. In order for this tion for each ½" error in finding the be ~,veral inches wide. Instead of the scheme to work, the intersection of the meridian by the compass. A coincidence front face being extended all the way to two mirrors (the rotational axis) now had would still be observed, but not at local the horizontal base, it was truncated, and to be elevated exactly to the latitude of the noon and at different times throughout a decorative scroll base was placed place of observation, whereas in ordinary the year. There are versions with a full below. These were ai~ made for Eur- (noon only) dipleidoscopes it was only compass or with a trough compass. My required to put it approximately into that opean latitudes, however. TM They could own example (Fig. 5) has a trough be used on a mounting plate or cemented direction. This instrument therefore also compass, with a range of W deviations in place directh'. carried a quadrant latitude scale in 1" from 4 to 36", appropriate for England in increments?' These instruments invari- the 18~)s when the magnetic deviation ably carried a full compass and two In the 1843 to the 1845 editions of Dent's (variation) was around 18'W. A very bubble levels, it is not clear when these pamphlets- another instrument is shown, curious arrangement was chosen for the were first made. I can only mention that 'suited to the observatory or library, base plate, one edge being aligned with the 1867 'Maryland' dipleidoscope ~was of where it should be placed on a pedestal the 2Or' central direction of the mmgh this type it is also quite obvious that either of .~tone or cast-iron' (Fig. lO).: TM compass. In this dipleidoscope there are this type had not yet been made for a very simply no angles, faces etc. that align long time, or that it was not a big seller, as it is the same basic dipleid,~,cope shown with any of the important directions in the instructions included with it were in Fig. 9, but its east face is mounted to a the horizon. It was the first dipleidoscope hand-written on the letterhead of 'E. Dent vertical plate with adjustment screws for I ever examined, and its correct placing & Co., 61 Strand, W.C.' and dated

32 Bulletin of the Scientific instrument Society No. 72 (2002) l"~i*'v[. 1845. Their tx~klet" shows genuine Dent dipleidoscopes. Later the firm made their own model, signed Secretan ~1 Paris. '4 These are very nicely made but quite large: Our example (Fig. 6) weighs a full 3,170 g, almost five times as much as a Dent ~roll-ba~ m~el. Incorporated into the ba~ is a worm screw 6w making azimuth fine adjustmenLs, and the ba~ can be tilted against the sub-ba~ by a screw to make the upper mirror (M1) vertical, as required. This instrument was available without (Fig. 6) or with a telescope.~

Acknowledgments

The following individuals generously supplied me with information on their Fig.ll "Mural'fl~rm qf dqqci,h~cot,e shown fl~r the first time in the dipleidoscopes, or helped in other ways: 1875 br~g'hure.; it is similar to the libraru form (Fig. 10) but mas Frederick W. Sawyer, Ill (Glastonbury, mounted permanently out of &~rs and protected by. a h~ckable zinc cozwr (not shown). CT, USA), Raymond V. Giordano (The Antiquarian Scientist, Southampton, MA, USA), Nell Brown (Science Museum London), A.D MorrLson-Low (Natitmal Museums of Scotland, Edinburgh), Glor- ia Clifton (National Maritime Museum, Greenwich).

Notes and References

I. D. Howse, Greena,k'h Time and the L~mg- itude (London: Philip Wil~m, 1997). 2. C. Stott and D.W. Hughes, 'The Ama- teur's Small Transit Instrument t~ the Nine- toenth Century,' Q. ]l R. astr. Soc. 25 (1987), pp 30-42. 3. N. yon Konkoly, Prakti.,~heAnleltun,¢ =ur Anstellung astronomischer Beobachtuncen (Braunschweig, 18~3). 4. L. Ambmnn, Handbuch der astrmunni~'hen Instrumentenkunde, 2 ~d vol. (Berlin, II¢,~9). 5. Marc Franqois Louis Secretan2~ (1804- 1867) m~t truly made 'prismatic' dipleido- scopes (see this paper), but also an instrument using a 45" prism ~4 based on the same pnnciple that Steinheil (1801-1870), PlOssl (17q4-1868) and Amici (1786-1863) u.,~-~l, l Fig.12. Dipleid¢~copefor taking time fixes at did'rent times during have not been able to establish pnordv for the day (from 9 a.m. to 3 p.m.) "u,hen great accuracy is not required' this idea. I am grateful to Paolo Brenni fl*r first shou,n in the 1875 brochure.: Graduated hour art" and setting for inlormation on an instnlment of this ~'pe, latitude. unsigned, but thought to be a "Meridiana [c~nantidiptica' by Amici, in the collection of the F¢~IdaziCme Scienza e Tecnica in Florence. September, 1867." After leveling and another model the axis of rotation of the A Plossl instrument is haqd in the .',k'wnce orienting the instrument properly by mirrors was geared to the hour and Museum, London (ins'. l~h',-16~;). means of the compass, taking into account minute hands on a clock face. The two 6. James Mackenzie Bloxam, 'Mendian In- the 'degree of variation E. or W.' examples of this type ~2 1 know of, struments.' Bratish Patent No 979~ (1843) This however, have no adjustment [or the patent describes the double reflectitmnin a very general way and is actually more technicall~,, Set the hour arc so that the Xll coincides elevation of the axis of rotation, and can co¢r¢~ than Lkmt's b~klets.: ]'he firstmstrd" with the diviskm on the index pointer. The be used only at a fixed latitude (except at merit pn~p~l consists of three stepped instrument will then shew the time at noon noon). Yet another type useful over a rt'~iecting planes m an c~'n arrangement. - To ascertain the time at any other hour, the range of hours also used a fixed latitude and n~ine spate is dedk-ated in the pattmt to hour arc must he set to the time requiredY mount, but in connection with the more this very uncomn~n form than to the 'pris- conventional hour arc. ~' These models matic' a rran}~ement of two mirrors and a glass Contrary to what one might expect, these om,'er tound in commercMI Dent dipleido- were not shown in the Dent booklets. scopes. The t~'dv surviving stepped mirror were apparently not used by rotating the dipleidoscope I ~ of is inventory number mirror assembly around the polar axis Wh:1313 in the Whipple Museum, C~,mbridge. until a coincidence was observed, fob Dent apparently took out a French patent 7. A D~'r:t,hon Dtpleuh~t~, lowed by reading the time on the scale. in 1844.2~ We have already mentioned E.J. Dent, t~f.the or Doubh'-Re~lectm~ Meruhan and Alhtude In- Instead, a time was set, and the operator that Lerebours and Secretan sold Dent strument: with Plain lnstnactionsfiw the Methc~t waited for the coincidence to occur. In yet dipleidoscopes in France, probably from ~ Using it in the Corr~'tmn of T~me-Keercrs

Bulletin of the Scientific Instrument Society No. 72 (2002) 33 (Lo~lkm, varu~u~ date~). I have seen the first 13. ! only present without proof the moot Science Museum, Oxford, Cambridge, and edttion (I&Lt), the k~urth (unchanged) of |IMS, unportant wsult~ of the mathematical analym, Edinburgh) haveone of these in their holdings. the fifth (1850) and a 'New Edition' (18"75; no which uses three-dimemkmal analytical geo- ! have found only one in a dealer or sales author, as Dent had died in 1853, but me~y (rotak.d sy~,~.ms of coordinates and catalogue in the lasA throe years ('res~ract, publL,d~*d by E. Dent & Co.). Likely the~ other such good inventions) in addition to the Catalogue 61, t995). were no nditiom between 1850 and 1875, or law of reflection. ! believe these results have alter 1875 previously been i& Another 'India' instrument is in the not publi.,dwd. Oxford History of Science Museum (inv. 8. V. Mercer, Th~ L~ and l.,rttersof Edu~rd ~hn 14. In an 1844 letter to the astnmomer Schu- 36482). Scroll-base dipleid(~-'opes for Euro- Dent Chronometer Maker and Stone Account of reacher," presumably Heinrich Chnstian Schu- pean latitudes are found in the Science Sm'c.ess0rs (London, 1977). Diplei&~cope ma- madx~ (1780-1850) at the Altona ol~tervatory, Museum, London (inv. 1876-102) and the Wrial on pp. 196-203 and pp. 18~-192 (plates). Dent states that the dipleido~:opewas so much Whipple Museum, Cambridge (inv. Wh:72). in demand am~mg his cusknne~ that he was 9. This amount was noted on a 1867 bill of unable to extend the sale to the trade. One of the 19. I am not aware of any 'library' models in sales for a dipleidoscolx, sold to a Mr. Geo.W. things that held him back was his inability to public or private collections. Dobbin in Maryland by the tmpocter, Jas. A. ~ sufficient 'parallel gla,~es.' He inquired 20. Example: Science Museum, London (inv. Waters t~ I~ton. imp,w't duty (35%) mcrea~ed wn Schumacher if these could be obtained on 19fl0-178). the c~t to the buyer to L'~.9.0, tw $10395, with the ctmtinent, adding '1 pay 3/6 for the 3 gla,,aes imixwter's comm~,~ion (10%) 5114.34. This bill ctnnplete as they are in the instrument.' 21. Examples: Whipple Museum (inv. is included with other material related to this Wh:472) and National Mantime Museum, 15. For all th~we interested in experimenting Greenwich (inv. AST 0235). See al.-~ now 24. ~urchase in the collectkm of the Maryland with a dipleidosct~0e it should he pointed out istoncal Society, Library, Balfimt~, U~A as that a soot-covered gla~,, is a I~r eye 22. Whipple Museum (inv. Wh:1314) and MS 1125. pn~ctor t~ unevenquality, sul~ect to smud- Science Museum (inv. 1917-9fl). I0. Dent sawnetimes more generally talks ging. A modem welding filter, just about 23. Three dipleidoso~:w,J with hour arcs from about the traun~it o( a star. In principle the darkest made, is an inexpensive and much the Greenwich museum (one with a latitude prek~able alternative. dipleidosoq~e could be used for that purpose, scale, int'. AS]" 02355, two without, inv. AST but truly with difficulfl,', as the several reflec- lb. G. Clitttm, Dlrrtt0r'v of British Scu,ntlfic 0183 and AST 0243) are shown in H. ttigton, titms invoh'ed badly attenuate the light Instrunwnt Makers 15~-185! (Ltmdon: Zwem- Sundmls - An Illustrated History of P(n'table Dials intensiw, and the image t~ a star after the met, l~5) gives the following lamd(m ad- (l~mdon: Philip WiL,~n, 2001), pp 121 & 122. internal double retlectitm is really hard to see. dresses: 1846-1851:33 Cockspur St and 34 In my t~qinkm the dipleid~r-.ct~e lespeoallv 24. In 1845 (the date of their dipleidosctTJe Royal Exchange; 1846:82 Strand; 185l: 6l bnw:hure") the firm (dr Lere~)urs and Sccretan without a viewing tek'~ct~e) L'~ elfectively Strand. Frtwn the addresses on Dent's bi~kleOf limt~l to ~erva~ (~ the sun. was run by Nicolas (or N*~I) Marie Paymal the followmg addresses can be established: Lmel~urs, the ~m of the founder and his 1843, 1845, 18.tO:82 Strand and 33 Cock~pur St, It. Anon.,/~" D~plnd,~',~v ou instrument nor- Swiss partner Secretan. After Lerebours' retire- 1845 and 1850: al~ M Royal Exchange. The ment in 1855 Secretan became the sole owner. ~lu'n br¢i~t¢ de Edu~rd ]. t)ent mw mstructara 18~0 edtti~m carr~ the anm~uncement that l~,ur r~l~r ~ manlw des." chrontnni'trrs et des The dipleidoscope in Fig. 6 thus dates from 'Edward J. Dent will shortly rtqmwe from 82, firm see h~rh~,,¢s,au ra~,yenJe cef m~trunwnt (Pans, 1845). Strand, to more conlnlodk)us premises at 61, after 18~5. For more on this E Bnmni, '19m century French Scientific Instrument This b~kleL puhli.'~ed by N-P h~ebm~rs ct Strand. two d~rs East of Mssrs. C~tts, and ~'cretan. place Ju P,,nt-Neu( 1.t uses Dent's own immediately opposite Bedfl~l Street.' After Makers [11: Lerebours and Secretan,' Bulletin engravmg~, right down to Dent's signature. of the Sceent{fic Instrument Soc/ety. No. 40 (1994), Dent's death the successor company, E(dward) pp. 3-6. Apparently Lerebours and Secretan ~dd Dent Dent & Co, was still at 61 Strand and 34 (also dtpleid~ct~es. L~ttq" ~ecretan devek~xM his 3~) Royal Exchange in 1875." own distmctwe pattern (.,,ee Fig. o and note Zq). Author's tuldress: 17. None of the 'big five' instrument collec- 3809 Birchu~x~d Dri~ 12 A. Aked, 'High N~m,' Bull. i¢the Brthsh tion,~ in the UK (in non iudgmental tm.ier of Boulder, CO 803~N, USA Suq,lud Socu'tu, No. ~2 (June 1~3), pp. 21-24. increasing latitude: Greenwich, Loudon e-mail: [email protected]

Market Place: Spring 2002

Arthur Middleton

~Ahen others and I first began to buy interx'ened. Suddenly, at the start of the the two auctioneers had indeed agreed to things at Christie's, the auctions were autumn 1975 .,,ea.~m, the two principal introduce the Premium at the same time, conducted in a quiet and decorous auction hou~ announced, together and to avoid unnecL~sary competition during manner at King ~,treet (hmg before the at the same time that they were to apply a the interim. The Parties almost made it to nois" and bustle of their South Kensington 'Buyers Premium', or a surcharge of 10% Court, until at the last minute lawye~ for rt~m~,) and the l~ts were .,~)ld in guineas. on t'o]aof the hammer price. This would he BADA pointed out that should the lhe auctioneer ~ould quickly recognize a pavaple b)' all buyers and regardless of deciskm go against them, then in theory familiar race and would ju.~t smile and tht cost of an,,' I~t, be it a few hundred each and every member might be held mutter your name at the fall of the pounds or a few million, which surcharge individually rt.'sponsible for the entire hammer" There was no question of having the auctioneers would kt~,p for them- costs of both sidt~. Constematiml: no to go through the bother of registering selves. ]here was much grumbling, member was willing to take the risk, and before the ~le. The old-fa~,hionl~l view amongst trade and private buyer, and the case was hastily abandoned, the ~t;ll prevailed, that Chrb, tie's was more the general orinion was 'well, .~) we lower auctioneers then z~eenas 'having got away reliable h~r ~'lling Old Masters and other our bids by the ~me amount'. Eventually with it'. So we were obliged m accept the paintings, drawings and water-colours, the British Antiqut.,s Deale~ As.~ciation premium. Over the years this has crept up while the other auctioneers, Sotheby's, (BADA) launched a law-suit accusing the to 17.5%, which together with tax is very half a mile north in Bond Street, .~dd the auctioneers of connivance. Yhe case was nearly 2(Y~.. (The British Revenue-Men turnlture and other baubles. [hen slowing considered gtK~d, with, apparently, copies suddenly realized that they were mi~ing business, falling profits and competition of correH~mdence available to show that ~mething, and demandedtheir cut.)

34 Bulletin of the Sc~'ntific Instrument S(w:iety No. 72 (2002) l

Fig. I l)ancmg ,~trl~, m I,~,,u~t ,to S¢';'rcs, with ttw a,vrl,I at their .feet ¢thnv i~ the p~'ket g/0h's): Parts, 24'" Nowmber 20¢~L I'H6tel Drouot, Maitre Oliz,ier Coutau-Begarie in omtrol i~. them.

Fig.2 Pocket c,,mwndmm bu Elias AIh'n, ch~'d, Sotheby's Olympia. S~tember 21~1. Courtesy ~,f Sotheby~.

I~uses announced that the .same commi~ sion would be charged to sellers. How convenient, once more. to erase competi- tion. And how strange, thinking back to the introduction of the Buyers Premium 20 years earlier, in similar circumstanc¢~. The crucial diffi, rence was that the present plot was hatched and introducedin the United States, where such activitit.'~ are not just illegal, being a breach of tl'..ir anti- trust laws, but a criminal, not a civil, offence. Back in [x~ndon, a senior director at Christie's, Christopher Davktge, rea- lized the mistakeand [~,inted a way out to his I~*ard: under U.S. law, tl~e first 'whistle-blower' to indicate a cartel is let off free, but all others are pr,~'t,ted. A (;rand Jury investigated S~,thebv's for Fig.3 Th,"~mu" th'm, m its ,,r~mal h'ath,'r Fig.4 The Elias AIh'n ,omtwndn, m. ,,twn. three years, with Br~,kes and ]hubman case. Court,'s~ i!f S,,th,'hy's. G,urh'sy Of ~thet~'s. prevaricating. 1-he weight of e~ idence was finally tcn~ much, and the Company plead~,d Guilty to charges of collusion Forward a few years, and the stewardship go with it. The idea apl~'aled to him, and Br~kt.'s and l~aubman were then indivi- of Sothebv's was passed from Lord so he bought a controlling intert=st, ~2",, of dually charged. Brt~,kes entered an early Gowrie (Margaret Thatcher's proton',) to the w,ting shar¢.,s. American-sh'le busi- "Guilty' plea, and then, before the eves ot the Earl of W¢~tmoreland. Lh.~pite the ness meth~|s were introduce~'|, which the fine art world - the public benche~ additional wvenue of the initial 10% included, for one long-suffering English were packed with art corrt~pondents and Buyers Premium, their profits iust .~'med director, policy meetings which began at senior dealers, not to mention rel~rter~ - to eval~,rate. By 1982, the Company was six o'ch~'k in the morning. Diana Bnn,k,,,s .,,he gave danmmg evidence against her .,~,en to be 'in play', in other words, was apl~,nted Chief Executive ()tficer. At h~s, who was promptly found gt,iltv a~, well. At the time of writing hi, ha~ not available for purcha~. The first pi~sible the end of each l~mdon ,,,fie she would be ~.'n .,~,ntenced, but is apl~,aling agalnst buyers were two unknown American on the telephone, quick to prai~, a g¢,~| bt,sin~smen, Messrs Cogan and Swid, the verdict. ]he apl'~,al is to be heard on r¢sult, but fierce to criticize a bad one - but April 2'", t~ late for this rel~rt, bvt the wh~ only claim to fame was that the,,' how could the experts in charge p~-,,,ibly results will be di~'us.,,ed in a future article. owned a factory that manufactured predict how an auction would go? rhev l)avidge left his i~ with a repuh'd multi- carpet-underlay. (.,~,e liulh.tms, l,,ts.~im.) were .,a, often having to iuggle high million l~und pa~'-off llis Lhatrman. While their offer was being 'considered', r¢.,servt.,s set by gret~iy vendors against a Anthony lennant, was al.~ charged, but Mr Ford, of the motor company, intro- down-turning market, in one Sl~'ciality or whde proh~,,ting his mn¢~'ence, chloe' to duced another gentleman. To the world of another. Ignoring all the other afore- stay .,~teh' at home, since the charge is not fine art, Adolf Taubman, to give him his mentioned baubk.,s, the heady profits of an extra¢htable offence in the Lnlted correct first name, was totally unknown, the late l~k and earh" lqC~)sw'ere made Kingdom the question then ar¢~,: what having made his fortune by constructing by selling Old Master and Impr¢ssionlst should Iat,bman do with hi~ controlling out-of-town shopping malls and in the paintings. ~theby's and Christie's batth'd shareholding, worth .,~m~e US$2~(I mil- process had become very rich indeed, head to head to win the contracts to .,~,ll lion? Clearh,' it would be ent=reh," im- acquiring the friends and trappings that them. Suddenly, in March iw~5, both prol~'r to h~dd on to them following h~s

Bulletin of the Scient|fic instrument .~lck,.ty No. 72 (2tX)2) 3~ Fig.5. lfl," 1-o1,'~t,, ,1,trol,~t,c. tn,nt ~,t,.w. In two amt a halt u,'ars it Fig.6 The ~h',h, astn~hlt,e, back z,ieu,. But u,hvn" is it now? lumped at thn'e att,ttons from £30,{~l t0 nearly £ lSO,{~lO.C,,urt,~y Courtesy t~. Christie's. 0[ Chrts ta"s. conviction, but who might buy them? decided the reserves were ttn~ high. ment but now al.,~ subject to the new And for how much, considering the Many Lots were un.~dd, or sold for change. And, just to compound every- bu~int.~s is now making a loss? The French under the published reserve, and Phillips thing, all ,sales are now held in Euros. But bu~int~sman Bernard Amault, boss of have now admitted that the ill-judged does this mean that an English dealer can LVMH, was suggestt~, only for a ~pokes'- h~rav cost Arnault £18(} million. He then send a vanload of stock to Paris, man to announce, official'h,; that 'there deci~.ted to split the Company into two, announce a sale, and on the day, get up was no interest in such a move'. Although, retaining the sale-r¢~ms in Geneva and on the rt~trum and wield the hammer, as at the time of going to press, it was New York for highly-priced jewellery, you can in practically any other Eur- reputt~ that Arnault was disl~sing of sih'er and pictures, but ~qling off the opean country? Oh dear...you didn't his |ntert~ts in Phillips, perhaps prior to entire United Kingdom operation, with really think the French would make it making a move on Sothebv's. The major it's smaller provincial rooms dotted that easy, did you? No. They never do. To ~hareholders of the non-v~~ting common around the country - to Bonhams. The operate there, nowadays, any foreigner _~hart~ are al~ keen to bail out. Mean- merger went through last autumn and must now apply for a licence from the while both houses have had to make the name 'Phillips' has been erased in the newly-established Conseil des Ventes, provi,,,ion to repay US$21'lO million each United Kingdom. A pity, since the firm and be vetted and approved. Only to ~,ttle class-action lawsuits brought in was founded in 1792. experienced and recognized auction the Lnited Statt_'s by irate buyers and The other big news is the opening of houses need apply. Others will have to ,,t, ller~, ~ho considered the)" wew over- wait. [But if a junior member of staff charged by the collusion. France to foreign auction competition. After delaying tactics which lasted more happens to be a handsome young While all this was going on, there was than six years, their Cawemment slowly Russian prince, from a good White much more .,,hurtling of the pack else- passed the necessary laws to reform thei'r Russian famil); impeccably dressed, flu- where. Bn~kes, the Cla~,sic Car specia- antiquated system, and thus ended the ent in five languages and with exquisite Ii~,t,,. ~uddenlv h~k over Bonhams. At monol~dy enjoyed by their auctioneers manners and the best connections, well, Phillip,,, the two major shareholders that had lasted since"15%, in November that does help...] decided to retire and .,~dd out to a firm and Decemher last year the two major Within the last eight months two senior of \i, nture Capitalists, who then .,~ld on hou~ held their opening sales at their figures have stepped down from their the bu.,,ine,,,; to the afore-mentioned respective Paris headquarters, Christie's rostrums. At the age of 65 Jeremy Collins Bernard Arnault. He decided to fund carefully timing their inaugural auction retired from Christie's in early May last I'hdhp~, which enabled their experts to to take'place on the very day, 235 years year, replaced by Tom Newth, and ion g,uarantee to the vendors of paintings - previously that lames C. held his very Baddeley has resigned from Sotheby's to large, inll~rtant but un-tt.~ted collections first sale in London. The new Buyers pursue a career at Windsor House - more money than any other auction Premiums they apply amount to a hefty Antk]ues Ltd. Together they have domi- house wa~ prepared to. I~or a .~hort time, 21% on Lots up to £9,500.00, thus nated the lamdon scientific instrument l'hllllp,~ in New York enloved a blaze of demolishing the previous 11.75'!,. which auction scene, and their absence will be publicity, but in the event the buyers had originally been set by the Cawern- missed. Jon's place is taken by his

Bulletin of the ~ientifi¢ instrun~mt .~:iety No. 72 (2002) colleague of recent years, Catherine rotmas Sotheby's offered one in opening (£5,500, hammer price) but still with Southon, who now becomes both ex- September sale - a Ix)cket compendium historical naval interest and written pert-in-charge and auctioneer. by Elias Allen, dating to between 1615 provenance from the family, was the and 1620 (Figs 2, 3 and 4). Only sixty pair-cased gold watch by Brockbank of Eighteen m(mths ago, in Paris, Maitre items by Allen are known, and this was London, hallmarked for 1776, with a Olivier Coutau-Begarie was invited to the eleventh compendium, it was in sweep seconds hand and still in perfect value and sell a house contents. Included superb condition, scarcely used, since working order. It had been used to time were boxes of scientific instruments, all the colours on the compass dial were the action during the sea-battle called purchased in the 1950s, 60s and early 70s, quite fresh, and still in it's original leather 'The Glorious First of June 1794', an early much from the late Peter Bmphy. Every- case. Together with the premium it cost encounter of the Napoleonic Wars be- thing had to be catalogued, advertized £48,500, and it might have made a touch tween the British and French Navies off and sold within one month. And so they more, but one by one the telephones fell the coast of Brittany. The British Channel were. The estimates were purposefully silent, for once, and the hammer fell to an Fleet sailed to intercept a large convoy of pitched low, indicating that everything English buyer in the room. French transports carrying a much- was 'to go' - five pocket gkd~es at £,5(}0- needed cargo of grain from America; a 800 each, (made an average of £2,500 The Toledo Astrolabe, made in 14 'h century Spain, continued to make head- French Fleet put out from Brest to escort each, see Fig.l); an early 19~h century them in, and gave battle. A Lieutenant on pocket thermometer signed Pugin/~ Lyon lines, in our terms. We have seen this instrument twice before (Figs 5 and 6). It board Lord Howe's flagship was ordered at £60-80, (which made £6(~, and cheap at to time and record the action, but having the price); a rare Georgian double-sided first surfaced at a general sale in Nancy, eastern France, in June 1998, making no watch of his own he hastily borrowed pocket compass with pedometer by this one from his cousin, who was Fraser of London, for £,3(}0-400, (made £30,000, and the purchaser promptly gave it to Jeremy Collins at Christie s. It serving in the same ship. The result of £1,700, and certainly not expensive); a the action was a victory for the Royal noon cannon for £250-300, (made £2,100, was the star Lot in the April 1999 sale at South Kensington. Then catalogued by Navy. Nine of the transports were but they have been known to make more); burned, one scuttled itself, six French and Lot 210, an ordinary-looking mid-19~ Professor David King, he considered it so important - 'unique', with inscriptions by warships were taken as prizes and one century French sextant in a tricorne case, three different hands and cultures - Latin, sank. Surely this watch should have be but it took a second look to realize that all Arabic and Hebrew - that his careful, bought bv the National Maritime Mu- the fittings, mirrors, filters and the fascinating details and illustrations ran to seum at C~reenwich?... But no. telescope holder were the wrong way twelve pages. The hammer price was round, and that it had been made to £70,000, probably the reserve against a My final thanks, again, to Jon Baddeley special order for a left-handed officer; published estimate of f,80,000-£120,000. and Jeremy Collins, who over many estimated at £,500, it made a modest £680. years have provided much material for In October 2001 it was again re-offered, The total proceeds were £150,000. the background to these reports. by Sotheby's in their Islamic sale, and made a total of £179,500. Had the buyer There are not many instruments coming Author's address: onto the market that date to the reign of Jewish, or Arabic interests? Sotheby's were unwilling to say. 12 New Row James 1, King of England (reigned 1603- Cotcnt Garden 1625), but at their new Olympia sale- A smaller item, for much less money London WC2N 4LF

Classified

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Bulletin of the Scientific Instrument ,Society No. 72 (2002) 37

I Rogers Turner Books 23a Nelson Road, London 5E10 ~JB 24 Rue du Bui~on Richard, 78600 Le Me~nil-le-Roi, France ALAIN BRIEUX Tel & fax O0 44 10)20 8853 5271 [el tX) 33 1 30 12 11 ql : Fax tX) 33 i 30 02 07 22 email roger~turner~com pu~,rve.com SCIENCES • TECHNIQUES • MI~DECINE

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Back Issues of the Bulletin

Iollo~ inu Ihe clearance Special ( )llL'r Ihere are no longer any hack i~ues axailable lbr numhers I to 5q ( ie up to I)ecemher 19q~).

lhe Sociely intends to Illake the x~ hole of Ihe Bulletin axailahle on ('I)R()M in the near fulure and members ~,, ill he kept in fornled of dex elopnlenls.

Any ¢nquirie.~ please contact lhe l-xecuti~e ()IHcer Vv'~ (.'dr (;col1"rey Bennett,

I(I ~, ~,e,l "~11~) ~lrt~.'l ~ (hat. Cahlornla ~.~112~ [dephunedac~lmde i ~(l~ i h4h-0204 ~ho r ()pen IO an1 Io :~ p m e~er) l-rlda), .~aturda). ,~unda) •rod Monda) or h) appomtmen!

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4R) Bulletin of the Scientific In.trument ~v.-iet)' No. 72 (2002) Current and Future Events

Until 31 July 2002, Ghent, Beisium not be repeated for the foreseeable future. Faking: A Progress Report on the Mensmg Venue:. The Royal Observatory. ~,mt. Exhibition Ha 'Cab/net de Phys~ue' van lose# Plateau in 1840, at the Museum for March $ - 9 9 - 14 .~q[~entber 2002" Athens, Gret,oP the History of the Sciences of the Conservation in Action. Museum conser- University of Ghent, Krijgslaan281, bldg vators will work on paintings and other XXI Sc~ti~ Instrument Symposium. The $30, B-9000 Ghent, Belgium. Catalogue artefacts, demonstrating various scienti- organizers are Eftymios Nicolafdis by L. Dorikens-Vanpraet and M. Dor- fic techniques used to clean and conserve ([email protected]) and Giorgi Viahakis ikens, and also a book by M. Dorikem, objects, including several to be displayed ([email protected]) at the National Hele- ]oseph Plateau 1801-1883. ~ tussen in the Museum's forthcoming gallery, nic Research Foundation, Vassileos Con- gunst en Wetensckap (Limng between Art Ocmns of D/scovery, opening June 2002. stantinou 48, 11635 Athens, ~. i and Science (Provincie Omt-Vlaanderen, Venue:. National Maritime Museum 2001). For information contact maurice.- Tunes: 10.00am - 5.00pro. s October 2oo2, Briml, ~ [email protected], website: http:// For further information contact:. mhsgent.rug.ac.be, or telephone +32 9 O2O 8858 4422 2644930. SIS Visit to Brunel instruments, Camera 020 8312 6565 (Recorded informatmn) University Bookings : 020 8312 6608 Obscura, Industrial Museum, Library, Tyndall Avenue, Bristol BS8 ITJ. 8 - 17 March 2002, National Science Or see the National Maritime Museum Week National Maritime Museum and and Royal Observatory Web Sitt~. Royal Observatory Greenwich www.nmm.ac.uk October 2002, Paris, France www.rog.nmm.ac.uk Sponsored by the National Physical Exhibition at the Paris Observatory an Laboratory 12 April 2002, London, Enslamal exhibition on Foucault, accompanied by a book by William Tobin in French and With over thirty different events and SIS visit to The Scknce Museum Reserve English. Contact Suzanne Dttbarbat at the around 340 different sessions, the pro- Collection, Blythe House, 23 Blythe Road, Paris Observatory, 61 Avenue de l'Obser- gramme for National Science Week ~002 Olympia, London WI4 0QE Catherine vatoire, F-750 14 Paris, France, for details. is Greenwich largest yet. The following Southon, Head of Scientific Instruments events may be of particular interest. at Sotheby's Olympia, has kindly invited participants after the visit to come to $atm~lay 9 March their adjacent premises at Olympia, The 33m Scientific ~ Medical Instrument Clocks and Scientific Instruments. An after- Hamnwrsmith Road. There will be drinks Fair will be held at the Radisson SAS noon of lectures for those interested in and the opportunity to view the instru- Portman Hotel, Portman Square, London docks and scientificinstruments. Mat- ments in their forthcoming Scientific Wl, /tom 10:00 to 16.4}0 hours. Nearest thew Read, Assistant Curator of Horol- Inset sale to be held on 30* May. Underground station is Marble Arch. ogy will focus on the conservation and Highlights in this sale include an armil- Admission £4. Oganized by Talbot maintenance of the museum's horolo~-'- tars] sphere by Wagner, dated 1540, and a Promotions, PO Box 31525, London cai collections, with practical hints ~r rare and probably unique simple micro- Wll 2XY. Telephone/fax: +44 (0)20 8969 collectors and owners of antique clocks. scope by John Marshall, c.1690. 7011. E-mail: [email protected] In the second lecture, Dr Gloria Clifton, Curator of Navigational Instruments, April ~ London, En#end 20 November 2002 - F~2003, will talk about collecting scientific instru- Parm, France J ments, providing help in identifying The 32~ Scientific & Medical Instrument some of tl~ most conunon fakes and Fair will be held at the Radisson SAS Exhibition Ti~ tke Terapl~ of Ancient forgeries in thin f~ld. Portman Hotel, Portman Square, London Venue'. National Maritime Museum. Egypt, cent~d~ upon a recently discov- W1, from 10:00 to 16:00 hours. Nearest ered aca~ statuette, formerly in the Ttmes: Underground station is Marble Arch. Clocks and Watches - Yune)~fuseum, Rockford, at the Mus~ Admission £4. Oganized by Talbot d~Arts et Mtttiersin Paris. Matthew Read - 2.00pro. Promotions, PO Box 31525, London Scientific Instruments- Wll 2XY. Telephone/fax: +44 (0)20 8969 25 November 2002, London, England Gloria Clifton - 3.30pro. 7011. E-mail: [email protected]

March 11-13 11 - 16 May 200Z V'mit to Gemmny The Society's 10~ Annual Invitation The C/ocks of the Royal Observatory. An Lecture will be given by the President, exclusive tour of the working horology SIS Annual Study Conference to Hamburg, Professor G.L'E. Turner at the Society of collections,including the Harrison time- Bremerbaven, Oldenburg, and Kiel. An Antiquaries, Burlington House, Picadilly, keepers, Tompion year-going docks, and internet site ht~://www.math.uni-ham- London W1V 0LQ. His title is Sc/ent/Jic astronomica/regulators by Graham, burg.de/math / ign / Info/sis02.htm gives instruments: Why.? Sheiton, Eamshaw and Arnold. further details of the programme. It has These tours must be pre-booked. been created by Gudrun Wolfschmidt, 30 September to 4 October 2003, Venue: Royal Observatory who is closely involved in the organiza- Newpoa News, Virginia, USA Tune 9.00am - 10.30am tion of this event, and attempts will be Fee £10 made to keep it updated. XXII ScimtiJic instrument S.~x~sium to be held at the Mariner's Museum at March 8- 17 10 July, AGM 2002, London, En#end Newport News, Virginia, with excursions /okn Harrison's Ti~, Although al- to Colonial Williamsburg and Washing- ways on display at Greenwich, few The Society's Annual General Meeting ton. Note that the XXlll Symposium will ~le have seen all four of the famous and Lectures at the Society of Antiqua- be held in Dresden, Germany, in 2OO4, Harrison marine timekeepers (HI, 1-12, ries,Burlington House, Picadilly,London and the XXIV Symposium, in principle in H3 and the prize-winning watch, H4) WIV 0LQ Speakers: Anastasia Filippou- Beijin~, China, in 2005. For information running together. As a special celebra- ~_i~ Sci~tiJic Instrument CoU~tions: consult the Commission's webeite at ti~., these revolutionary pueces of science Engi mgish at Material Culture of 19~ Century http://www.sic.iuhps.org aria engineering technology will all be Science; Allan Mills: Tassels and running for the duration of National Bonnets: Early History of Insulated Copper Details of future events, m~,tings, ~hibi- Science Week, an opportunity that will Wire;, and Stephen Johnston: Making and hans, etc. should be sent to the Editor. Table of Contents Appml~te mak.ml ~ be ~ in PIg,~O Abara~

..... oooooooo..o..o ...... • ...... oooo••o• .oooo.oo.•o •ooooo•.o.o•o•.o.o.ooo•oooo•oooooooooooooo.oooo•oooooo •*ooo• oooooooooo.o oo,ooooo•.ooo•ooo.oo•**o.oo****oooo**oooo,ooo.ooo***oo..ooo,~.~,oooooooo,.o ] Cover Story ...... WtUm tl,ckaum 1 Annua/Imntation Lecture From Graduations on Metal to Binary Bipluue Moduiatk~ or From Land and Hydrographic Surveying to ~tics ...... Mk:had Cooper 2

The'H~Tre, mm~ mlhe//lu~md~Nam ...... Pet~de~ II J.B. Micheli du ~'s Themvxne~ and The Connectiom with G.F. Br, nder ...... Sok Talm 20 ]'he DtpletdmcoW Uncovered ...... Paul Zoller M*rkt.¢ i'hce: Spnng Z002 ...... Arthur t,C~tdktm 34 Adv~ ...... 37 Current and Future Events ...... imide back covw

The Scientific Instrument Society Membership

The Scientific ~ Society (SIS) wu kxmed m April 1963 to bring ~ people w#h a qx~ci,li,t intenmt m tcimc¢~ ~u. rangu~ h-m ~ ,nt~lue, to ~ ,k.vtc~ only rm~tiy out o~ ~

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The SIS Bulletin

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