Michael Bycroft

Home , Mercure de France, Rocaille, Rococo

Journal of Interdisciplinary History, XLVIII:3 (Winter, 2018), 359–384.

Michael Bycroft Style and Substance in Rococo Science “Rococo science” might seem to be a jarring term, and not just because we are accustomed to placing “art” and “science” in different categories. Consider the following statements, one about a set of ornamental engravings and the other about a theory of electricity. The first comes from the Mercure de France, the unofficial organ of the style rocaille in 1730s Paris, and the second from the Histoire et Mémoires of the Royal Academy of Science, the official organ of French science in the same period: (1) “There has appeared a suite of engravings in wide format that will pique the curiosity of the public and of curious people [curieux] of the best taste. These are fountains, waterfalls, ruins, rock-work, shells, and pieces of architecture that produce bizarre, singular, and picturesque effects [effets bizarres singuliers et pittoresques] through their strange and enticing forms [ formes piquantes et extra- ordinaires], of which no parts agree with the others.”1 (2) “Such are the simple and primitive facts [ faits simples et primitifs] to which all known experiments on electricity may be reduced; the number of such principles will diminish as we acquire a more exact knowledge of electricity, which until now was known only by a few very complicated experiments [expériences très-compliquées] that de- pended on bizarre circumstances [circonstances bizarres]. Now we know that electricity is a general quality of matter that depends on invariable principles [ principes invariables]andissubjecttoexactlaws[loix exactes].”2

Michael Bycroft is Assistant Professor in the History of Science and Technology, University of Warwick. He is the author of “Iatrochemistry and the Evaluation of Mineral Waters in France, 1600–1750,” Bulletin for the History of Medicine, XCI (2017): 303–330; “Wonders in the Academy: The Value of Strange Facts in the Experimental Research of Charles Dufay,” Historical Studies in the Natural Sciences, LXIII (2013): 334–370. © 2017 by the Massachusetts Institute of Technology and The Journal of Interdisciplinary History, Inc., doi:10.1162/JINH_a_01162

1 Mercure de France, March 1734, 558–559, quoted in Alastair Laing, “French Ornamental Engravings and the Diffusion of the Rococo,” in Henri Zerner (ed.), Le stampe e la difusione delle immagini e degli stili, Atti de XXIV Congresso Internazionale di Storia dell’Arte (Bologna, 1979), 113–114. 2 Charles Dufay, “Sixième mémoire sur l’électricité: Où on examine quel rapport il y a entre l’électricité et la faculté de rendre de la lumière, qui est commune à la plupart des corps électrique, et ce qu’on peut inférer de ce rapport,” Mémoires de l’Académie Royale des Sciences (herein MAS) (Paris, 1736), 525–526. This volume of the Mémoires comprised papers read to the Academy in 1734.

Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/JINH_a_01162 by guest on 28 September 2021 360 | MICHAEL BYCROFT Both passages appeared in 1734, but their similarities end there. For the reviewer in the Mercure de France, “bizarre” was a term of appreciation. For Dufay, the author of the second passage, it denoted dissatisfaction. For the reviewer, the value of the engravings under review, executed by Gabriel Huquier but inspired by the goldsmith Juste Aurèle Meissonnier, lay in their irregularity, that is, in the strangeness of their forms and the disagreement between their parts. For Dufay, the value of electricity lay in its regularity, that is, in the generality of its phenomena and the exactness and invariability of its laws. The point of Dufay’stheoryofelectricitywastodiscover a small number of principles—the fewer the better—that framed the known facts about electricity. By contrast, the point of the engravings was to overwhelm the frame with a profusion of detail: In Figure 1, the curvaceous structure on the left of the engraving ap- pears to frame the image, but it is overrun by the fountain in the center of the engraving, fading into the background on the right. Both the theory of electricity and this engraving were human creations intended to represent the natural world. But the theory was meant to represent nature per se, whereas the engraving was an artful imitation of nature that blended natural bodies (rocks, shells, and waterfalls) with the fantasy of the artist. These antitheses—regularity versus irregularity, structure versus the play of surfaces, and the separation of art and nature versus the

Fig.1 Engraving after Meissonnier

SOURCE Gabriel Huquier, Oeuvre de Juste Aurèle Meissonnier (Paris, n.d.), reproduced in Fiske Kimball, The Creation of the Rococo Decorative Style (New York, 1980), 323, Figure 209.

Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/JINH_a_01162 by guest on 28 September 2021 STYLE AND SUBSTANCE IN ROCOCO SCIENCE | 361 conflation of those two categories—were not peculiar to Dufay and Meissonnier. They apply broadly to the artistic productions of the rococo period and to the scientific productions of the early Enlighten- ment, most clearly in Paris between 1710 and 1740. This article shows that this divergence is merely apparent. The stylistic differ- ences between academic science and rococo art dissolve if we pay attention to their common concern with making and manipulating substances. Decorative substances—especially gold, gems, lacquer, porcelain, wrought iron, and dyestuffs—were central to experimental research at the Academy of Science during the three decades in question. René Réaumur and Dufay, two of the men who dom- inated this experimental program, examined these materials in their search for cheaper and more efficient techniques in the decorative arts. They were concerned as much with the beauty of their products as with cost and efficiency, and their notions of beauty resembled those of rococo artists. Moreover, their interest in the style and substances of rococo art was not merely utilitarian. Their study of these substances fed into fundamental research in what we now call chemistry, physics, and mineralogy, and this research was sustained not just by the substances themselves but also by the very properties that made those substances rococo—their irregularity, their spectac- ular surfaces, and their imitative qualities. “Rococo” and “science” are a natural pairing when we examine the substances that scientists and artists had in common and the ways these substances under- pinned the rococo style.

ROCOCO ART AND ENLIGHTENMENT SCIENCE This article attempts to solve the historical paradox embodied in Dufay’s theory of electricity and Meissonnier’s designs: How can we explain the co- existence of two such contrasting cultural products in the same city in the same year? The question is worth asking because Dufay and Meissonnier were men of their time. For intellectual historians, Dufay exempliﬁes an epistemological and metaphysical shift that occurred in the natural sciences during the early decades of the eighteenth century. Seventeenth-century natural philosophers had reveled in strange and anomalous phenomena, in the irreduc- ible complexity of nature, and in the interaction between natural bodies and human artifacts. Their eighteenth-century counterparts replaced anomalies with generalities, favored simple rules over rich descriptions, and drew a sharp line between artifacts (the direct

Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/JINH_a_01162 by guest on 28 September 2021 362 | MICHAEL BYCROFT products of human action) and natural bodies (now understood as the products of laws decreed by a remote God). This new approach to nature, which emerged in the latter part of the seventeenth century, was ﬁrmly in place at the Academy of Science in the second decade of the eighteenth century.3 For historians of art, Meissonnier’s sinuous candlesticks are typ- ical of the French rococo, a stylistic movement with a similar time- table to that of early Enlightenment science. According to most standard accounts, this movement had its origins among interior decorators working for Louis XIV late in his reign. It gained momen- tum during the Regency of Philippe II (1715–1723), in the redecoration of the Regent’s Paris residence the Palais Royal, in Parisian interiors commissioned by such wealthy ﬁnanciers as John Law and Pierre Crozat, and in the paintings of Jean Antoine Watteau and Jacques de la Joue. It climaxed during the 1730s and 1740s with the interiors designed and executed by the sculptor Nicolas Pineau, the paintings of François Boucher and Jean Baptiste Siméon Chardin, and, above all, the gold- and silverwork of Meissonnier, which were, in the words of one authority, “the most extreme, characteristic, and novel expression” of the movement. Known at the time as “le goût moderne,”“le goût du siècle,” the “genre pittoresque,” or the “rocaille,” the movement has been known since the end of the eighteenth century as the “rococo,” a term that began as a slur but evolved into a neutral descriptor for a distinctive phase in French painting and decoration.4

3 For an influential statement of this view, see Lorraine Daston and Katharine Park, Wonders and the Order of Nature, 1150–1750 (New York, 1998), 352 (Dufay). See also Daston, “The Cold Light of Facts and the Facts of Cold Light: Luminescence and the Transformation of the Sci- entific Fact, 1600–1750,” Early Modern France, III (1997), 1–27; idem, “Nature by Design,” in Caroline A. Jones and Peter Galison (eds.), Picturing Science, Producing Art (New York, 1998), 233–253; idem, “Preternatural Philosophy,” in idem (ed.), Biographies of ScientificObjects(Chicago, 2000), 40 (Dufay); Christian Licoppe, La formation de la pratique scientifique: le discours de l’expérience en France et en Angleterre (1630–1820) (Paris, 1996), 46, 98, 113–116, 118–119. 4 Fiske Kimball, The Creation of the Rococo Decorative Style (New York, 1980), 161 (“most extreme”). The chronology sketched herein is based on Hans Sedlmayr and Hermann Bauer, “Rococo,” inMassimoPallottinoandBernardS.Myers(eds.),Encyclopedia of World Art (New York, 1966), XII, 247–251. Sedlmayr and Bauer follow closely, though not exactly, Kimball’s chronology in Creation of the Rococo,assummarizedinidem, “The Creation of the Rococo,” Journal of the Warburg and Courtauld Institutes, IV (1941), 119–123. For syntheses that follow a similar chronology, see Eric Hubala, Baroque and Rococo (London, 1989; orig. pub. in German, 1971), 166; Germain Bazin (trans. Jonathan Griffin), Baroque and Rococo, (London, 1979; orig. pub. in French, 1964), 194; John Whitehead, The French Interior in the Eighteenth Century (London, 2009; orig. pub. 1992), 54–61; for an up-to-date summary of the history of the terms employed to name the movement, Colin B. Bailey, “Was There Such a Thing as Rococo Painting

Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/JINH_a_01162 by guest on 28 September 2021 STYLE AND SUBSTANCE IN ROCOCO SCIENCE | 363 For some, the term rococo has fallen into disrepute. “Rococo is a bad word,” Scott writes in her foreword to Rococo Echo; more gener- ally, style is “so obsolete . . . as a critical concept that recent dictionar- ies of art historical terms have sometimes made a point by omitting it.” The terms rococo and style may not be as fashionable now as they were in 1943, when their German equivalents appeared in the title of Kimball’s Creation of the Rococo Decorative Style, but they still appear meaningfully in many recent scholarly works, including encyclopedias, surveys, monographs, book reviews, and edited collections. The tendency since 1943 has not been to revise radically the list of formal qualities that made up the rococo style but to place those qualities in their social, political, and economic context. Scott’s pioneering work about the rococo interior is one of several examples of this phenom- enon. She agrees with Kimball that, for example, decorators under Louis XIV tended to conﬂate architecture with ornament. However, Scott explains this stylistic tendency in terms of court politics whereas Kimball invokes “the mystery of personal artistic individuality.”5

in Eighteenth-Century France?” in Melissa Lee Hyde and Katie Scott (eds.), Rococo Echo: Art, History and Historiography from Cochin to Coppola (New York, 2014), 169–190, 169–174; Kimball, Creation of the Rococo,3–6. 5 Scott, “Foreword,” in Hyde and Scott (eds.), Rococo Echo,2–3(“bad word . . . obsolete”). For encyclopedias, see Harold Osborne and Mark Jordan, “Rococo,” in Hugh Brigstocke (ed.), The Oxford Companion to Western Art (New York, 2001); Mary Sheriff, “Rococo,” in Alan Charles Kors (ed.), Encyclopedia of the Enlightenment (New York, 2003); for surveys, Minor, Baroque and Rococo,8,15,16–17; Gauvin A. Bailey, Baroque and Rococo (New York, 2012), 21; Whitehead, French Interiors,54–61; for monographs, Thomas E. Crow, Painters and Public Life in Eighteenth-Century Paris (New Haven, 1985), 7, 11, 44, 65 (“Rococo style”); Hyde, Making Up the Rococo: François Boucher and His Critics (Los Angeles, 2006), 11 (“rococo style of decoration and painting”); Gauvin A. Bailey, Spiritual Rococo,1–2; for reviews, Jeffrey Collins, “Style and Society: Painting in Eighteenth-Century France,” Eighteenth-Century Studies, XLI (2008), 569 (“style”); Emma Barker, “Rehabilitating the Rococo,” Oxford Art Journal, XXXII (2009), 306 (“style of painting”); for edited collections, Gauvin A. Bailey, “Rococo and Spirituality”; idem, “Rococo Painting,” 169–190; Brigid von Preussen, “‘AWildKindofImagination’:Eclecticism and Excess in the English Rococo Designs of Thomas Johnson,” in Hyde and Scott (eds.), Rococo Echo,191–213. Scott, Rococo Interior, ix (endorsement of Kimball’s “chronology and nomenclature”), 125 (decoration under Louis XIV); Kimball, Creation of the Rococo,6(“artistic individuality”), 59–111 (decoration under Louis XIV). For other examples, compare the list of qualities in Hyde, Making Up the Rococo, 11, with those of Sedlmayr and Bauer, “Rococo,” 239 (“rocks, shells . . . tumbling motion...iridescence...light-huedtones”), 241 (“lighthearted play”), 251 (“warmer” colors, “smooth . . . porcelainlike ﬁrmness”). Consider also the familiar stylistic traits mentioned in Gauvin A. Bailey, “Rococo and Spirituality,” 240 (“C-scrolls”), 241 (“celebrate nature and play”), 244 (“the sparkle of the gilding, the soft colours and the lightness of the décor”), 246 (“atmo- sphere of levity and brightness”); Preussen, “English Rococo Designs,” 193 (“stylistic hybridity and asymmetry”), 211 (“eclecticism, excess and whimsy”).

Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/JINH_a_01162 by guest on 28 September 2021 364 | MICHAEL BYCROFT No doubt, the phrase “rococo style” can be construed in ways that are conceptually confused or historically inaccurate. The solu- tion is not to avoid the phrase but to avoid such misunderstandings. To use the phrase is not to say that the rococo was the dominant style of painting or decoration in eighteenth-century Paris; that the term rococo was used in this period to designate the style; that the style was invariable over time or across genres; that it arose inde- pendently from social and economic concerns; nor that a single cause can explain the pattern of formal qualities that comprise the style. All that is required for this article is that there was such a pattern in Paris in the period 1710 to 1740, and that the qualities that made up the pattern included irregularity, superficiality, and imitation.6 Three qualities are common to many definitions of the rococo movement, both old and new—irregurality, superficiality, and imitation. Irregularity has been designated by phrases such as “ornements irréguliers du meilleur goût français,”“departure[s] from the normal and expected,” and “the irregular and the anomalous.” These traits were most obvious in the asymmetrical designs of Meissonnier, but they were also present in the gravity-defying figures in Louis XIV arabesques, the loose treatment of the “orders” of classical architecture, and the fluid view of gender identity implied by Boucher’spaintings.7 Superficiality was central for Kimball, who held the conflation of depth and surface as “the essential creative act in the genesis of the rococo.” Subsequent writers have furnished further examples of this theme: In the designs of walls and ceilings, pilasters gave way to slender fillets and horizontal borders to sinuous ones; in domestic furnishings, the play of surfaces was enhanced by strategically placed mirrors, windows, and light-fittings, and by the use of glossy materials (lacquer, porcelain, silk, gold leaf, and polished wood) on clothes and

6 This paragraph draws from the sensible discussions of “style” and “rococo” in Kimball, Creation of the Rococo,3–10; Minor, Baroque and Rococo, 8, 15; Gauvin A. Bailey, Baroque and Rococo, 21; and Collins, “Style and Society,” 569, 574. 7 Gauvin A. Bailey, “Rococo and Spirituality from Paris to Rio de Janeiro,” in Hyde and Scott, Rococo Echo, 243 (“ornements irréguliers”), citing a late eighteenth-century councilor in Brazil; Henry Fowler, A Dictionary of Modern English Usage (Oxford, 1926), 616, cited in Minor, Baroque and Rococo: Art and Culture (London, 1999), 14; Minor, Baroque and Rococo,14(“irregular” and “anomalous”); Kimball, Creation of the Rococo, 162 (asymmetry); Whitehead, French Interiors, 59 (asymmetry); Scott, The Rococo Interior: Decoration and Social Spaces in Early Eighteenth-Century Paris (New Haven, 1995), 123–133 (arabesques); Sedlmayr and Bauer, “Rococo,” 236–237 (classical orders); Hyde, Making up the Rococo: François Boucher and His Critics (Los Angeles, 2006), 145–202 (gender identity).

Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/JINH_a_01162 by guest on 28 September 2021 STYLE AND SUBSTANCE IN ROCOCO SCIENCE | 365 furniture; and solemn history paintings, gravid with theological and political symbolism, gave way to Watteau’s dreamlike pastorals and Chardin’s charming scenes of bourgeois life. The primacy of surface over structure was manifested in the ubiquity of ornament: Interior ornament was the “primary sphere” of the movement; ornamental engraving was its “ideogram”; and excessive ornamentation (“ornements surchargés,”“ornemens bizarres & de travers,”“ornements contournés”)wasa favorite target of its critics.8 Finally, there is broad agreement that imitation was part and parcel of the rococo style, whether in the form of glass beads that resembled natural pearls, French lacquer that resembled the Japanese original, colored paper that gave the appearance of cut velvet at a fraction of the price, or miniature diamonds and mirrors that shone like their larger, aristocratic counterparts. Imitation ﬂourished in print as well as in materials, most obviously in printed engravings, known as “découpes,” designed to be stuck onto furniture to imitate the designs of decorators like Pineau and painters like Watteau. French artists embraced anomalies, surfaces, and artful imitations at the very time when French scientists appear to have shunned these phenomena.9 This article is not the ﬁrst attempt to solve this paradox, but it is a departure from its antecedents. Art historians have long associated the French rococo with nature and with the empirical study of nature, noting the presence of natural objects (shells, rocks, waterfalls, stalag- mites, and so on) in ornamental engravings and identifying a strain of naturalism in the works of rococo painters (“all his endeavor was to follow nature,” as Levey writes of Watteau). Historians have also drawn analogies between the sensual aesthetic of the rococo movement and the sensationalist epistemology of philosophes such as

8 Kimball, “Creation of the Rococo,” 121 (“essential creative act”); Bazin, Baroque and Rococo, 177 (pilasters and horizontals); Sedlmayr and Bauer, “Rococo,” 239 (furnishings); Kimball, Creation of the Rococo, 3 (primary sphere); Hubala, Baroque and Rococo, 167 (ideogram). The phrases in parentheses come from, respectively, Voltaire (1733), Antoine-Joseph Dezallier d’Argenville (1787), and the Académie Française (1935), as quoted in Scott, Rococo Interior,253; Kimball, Creation of the Rococo,5,180–181. 9 For pearls, see under the heading “Substances in Science” below; for textiles and mirrors, Scott, Rococo Interior,38–39, 31; for diamonds, Sedlmayr and Bauer, “Rococo,” 239; Archives Nationales, T/1490/18, 853v; for découpes, Scott, Rococo Interior,246–252; Laing, “Ornamental Engravings,” 115; for lacquer, Monika Kopplin, “Naissances des laques françaises dans le contexte européen du XVIIe siècle,” in Anne Forray-Carlier and idem (eds.), Les secrets de la laque française: Le vernis Martin (Paris, 2014), 15–16; Forray-Carlier, “LesdébutsdesMartin,” in idem and Kopplin (eds.), Vernis Martin, 54, 55, 57; Sedlemayer and Baouer, “Rococo,” 269(therococoas“the illusioniz- ing of art”).

Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/JINH_a_01162 by guest on 28 September 2021 366 | MICHAEL BYCROFT Étienne Bonnot de Condillac. Recently, historians of art and science have made these connections more precise by focusing on the role of shells in painting and in natural-history treatises. Not only were shells a common motif in rococo design, but the principles of variety and symmetry were also common to the classification of shells and the decoration of dining rooms. Moreover, the community of shell collectors overlapped with the community of painters, art dealers, and art collectors. This article extends these insights into three new areas: the experimental sciences (especially chemistry and experimental physics), as opposed to natural history; the decorative arts, as opposed to painting and sculpture; and the activities of individuals who were prominent members of the Paris Academy of Sciences (Dufay and Réaumur), as opposed to those who worked on the mar- gins of the Academy (such as the art dealer Edme-François Gersaint and the writer and collector Antoine-Joseph Dezallier d’Argenville). The net result is a broader and deeper conception of rococo science, one that connects the major stylistic concerns of the decorative arts to the major scientificconcernsoftheAcademy.10 This connection becomes visible when we consider style and substance together, an approach that is not as common as one might expect. Consider two recent (and very good) edited collections that argue for a connection between art and science in early modern Europe—Science in the Age of Baroque and Laboratories of Art.The first volume is about the stylistic affinities between scientists and artists. Its authors identify three paradoxes that applied equally to both groups in the seventeenth century, the age of Newton and Boyle as well as Vermeer and Rubens. The other volume is about

10 For natural objects, see Kimball, Creation of the Rococo,153,161;Whitehead,French Interiors, 56; for painting, Michael Levey, Painting and Sculpture in France, 1700–1789 (New Haven, 1993), 29 (“all his endeavor”), 1 (eighteenth-century French painting), 43 (Watteau); Bazin, Baroque and Rococo, 203 (Chardin’s “naturalism”); for senses, Sedlmayr and Bauer, “Rococo,” 238, 241 (nature deﬁned in the Encyclopédie); Jennifer Dawn Milam, Fragonard’s Playful Paintings: Visual Games in Rococo Art (Manchester, 2006), 156–157 (Condillac); for a summary of recent work about Enlightenment themes in the rococo, Gauvin A. Bailey, The Spiritual Rococo: Decor and Divinity from the Salons of Paris to the Missions of Patagonia (Burlington, 2014), 4–5; for shells, Laing, “Ornamental Engravings,” 114–117; Scott, Rococo Interior, 166–176; Emma Spary, “Scientiﬁc Symmetries,” History of Science, XLII (2004), 1–46; idem, “Rococo Readings of the Book of Nature,” in Marina Frasca-Spada and Nick Jardine (eds.), Books and the Sciences in History (New York, 2000), 255–275; Bettina Dietz, “Mobile Objects: The Space of Shells in Eighteenth- Century France,” British Journal for the History of Science, XXXIX (2006), 363–382; Daniela Bleichmar, “Learning to Look: Visual Expertise across Art and Science in Eighteenth-Century France,” Eighteenth-Century Studies, XLVI (2012), 85–111.

Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/JINH_a_01162 by guest on 28 September 2021 STYLE AND SUBSTANCE IN ROCOCO SCIENCE | 367 the substances that alchemists and artisans had in common and about the tools that they used for making and manipulating these substances, whether in the artisan’s workshop, in the alchemist’slabo- ratory, or (more often) in multifunctional spaces that combined elements of the two. The words porcelain, glass,andgold occur rarely in Science in the Age of Baroque, and never to describe procedures for making those substances. Conversely, the words baroque, rococo,and mannerism do not occur in Laboratories of Art. The former volume does cover the processes of art and science—the process of drawing, for example—but not the process of making substances. The latter volume does cover the products of art and science—especially porcelain, glass, and gold—but not the stylistic features of these products. This disconnect does not diminish the merit of either volume, but it certainly leaves room for studies that merge art and science by merging style and substance.11

SCIENTISTS AND SUBSTANCES The institutional framework for much rococo science was the program of useful research pursued by members of the Royal Academy of Science in Paris. Utility had been a major theme of the Academy since its founding in 1666, but this theme became more formal, and more visible to the read- ing public, during the first few decades of the eighteenth century. Both shifts were reflected in the preface to the first volume of the Academy’s Mémoires (1701), written by Bernard le Bovier de Fon- tenelle, the Academy’s Permanent Secretary. Fontenelle wrote at length about the utility of the sciences, by which he meant the promotion of the experimental method, the dispelling of igno- rance in society at large, and, above all, the improvement of navi- gation, cartography, human health, and “les Arts” (the arts being a capacious category that included industries such as mining and shipbuilding, as well as decorative arts such as goldsmithing, gem cutting, and porcelain making).12

11 Ofer Gal and Raz Chen-Morris (eds.), Sciences in the Age of Baroque (New York, 2012); Sven Dupré (ed.), Laboratories of Art: Alchemy and Art Technology from Antiquity to the 18th Cen- tury (New York, 2014). 12 Robin Briggs, “The Académie Royale des Sciences and the Pursuit of Utility,” Past & Present, 131 (1991), 38–88; Henry Guerlac, “Some French Antecedents of the Chemical Revo- lution,” Chymia, V (1959), 73–112; Alice Stroup, A Company of Scientists: Botany, Patronage, and Community at the Seventeeth-Century Parisian Royal Academy of Sciences (Berkeley, 1990); Bernard le Bovier de Fontenelle, “Preface,” Histoire et Mémoires de l’Académie Royale des Sciences (1699), iii–xi.

Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/JINH_a_01162 by guest on 28 September 2021 368 | MICHAEL BYCROFT The improvement of the arts went hand-in-hand with the inte- gration of science and the state. Around 1700, the chemist Wilhelm Homberg convinced Philippe Charles, the Duke of Orléans, to whom he taught chemistry, that industry could not flourish without natural philosophy. In 1710 or 1711, Réaumur was appointed to lead the Academy’s project of describing the arts and trades practiced in France, and a decade later he published the first treatise on this project, a study of steel and iron. Between 1715 and 1718, Réaumur worked with the Duke of Orléans, now the regent of France, to compile a survey of the mineral and vegetable resources of the kingdom. In 1731, Dufay, one of Réaumur’s protégés, became the first member of the Academy to be appointed to the Bureau du Commerce, an office established in 1700 to regulate and stimulate the French econ- omy. In 1739, Dufay was succeeded at the Bureau by Jean Hellot, his friend and literary executor. These developments reflect the convic- tion, which derived ultimately from Francis Bacon, that natural philosophy and the arts worked best in concert. As Réaumur put it, “The useful, if looked at carefully, always contains something of theoretical interest, and it is rare if the theoretically interesting, when pursued, does not lead to the practically useful.”13 The utilitarian dimension of the Academy’sresearchhasreceived far more attention from historians than its aesthetic dimension, but beauty and utility are difficult to distinguish in the work of the four chemists just mentioned, especially in that of Réaumur and Dufay. As Réaumur wrote in his 1722 treatise regarding iron and steel: “The production of more beautiful work, without sacrifice of quality and at lower cost, is the route to progress which we must endeavor to guide the arts.” Réaumur’s aethestic interests are not obvious in the first half of the treatise, where he outlined a new procedure for convert- ing iron into steel that he considered more efficient, reliable, and economical than existing procedures. But beauty was paramount in the second part of the treatise, where Réaumur described a procedure for making cast iron malleable; the point of the procedure was to make cast iron that could be worked as finely as wrought iron.

13 David Sturdy and Christine Demeulenaere-Douyère, “Introduction,” in L’Enquète du régent, 1716–1718: sciences, techniques, et politique dans la France pré-industrielle (Turnhout, 2008), 14 (Homberg), 16 (Réaumur); Guerlac, “French Antecedents,” 78–80 (Hellot). Réaumur, L’Art de convertir le fer forgé en acier, et l’art d”adoucir le fer fondu (Paris, 1722), 8. Quotation from Cyril S. Smith (ed.) (trans. Anneliese G. Sisco), Réaumur’s Memoires on Steel and Iron (Chicago, 1956) (page reference from the 1722 French edition).

Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/JINH_a_01162 by guest on 28 September 2021 STYLE AND SUBSTANCE IN ROCOCO SCIENCE | 369 Fig.2 Design of a Door-Knocker

SOURCE René Réaumur, L’Art de convertir le fer forgé en acier, et l’art d’adoucir le fer fondu (Paris, 1722), 528 (from plate 16).

Réaumur’s ultimate goal was to manufacture cheap and attractive consumer goods. To this end, he dedicated a chapter in the treatise to an inventory of such goods—from locks to sword hilts to coffee pots—that could (he claimed) be successfully executed in malleable cast iron. His descriptions of these goods reveal an unmistakably rococo aesthetic in which ornement was the key term (see Figure 2). The “ornements” on balconies and banisters, Réaumur enthused, could now be done in iron rather than copper; iron chimney-pieces could now be made “orné” at a much lower price than before; and cast-iron key locks would be made even more “orné” than their wrought-iron predecessors. In Réaumur’s view, progress in the arts meant “making goods that are more desirable and more ornate.”14

14 Réaumur, Art de convertir, 529 (“beautiful work”), 530 (balconies and balustrades), 532 (chimney-pieces), 534 (locks), 547 (in general). The decorative and aesthetic aims of Réaumur’s treatise are ignored in most existing studies—for example, Arthur Birembaut, “Réaumur et l’élaboration des produits ferreux,” Revue d’histoire des sciences et de leurs applications, XI (1958), 151–155; Briggs, “Utility,” 76–77; Guerlac, “French Antecedents,” 89. The exception is Smith, “Introduction,” Réaumur’sMemoiresonSteelandIron.

Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/JINH_a_01162 by guest on 28 September 2021 370 | MICHAEL BYCROFT The ties between Réaumur’s study of steel and iron and the rococo movement thicken when we look beyond his treatise. The study was supported by the Regent, who arranged to import steel from places as far away as Cairo to help Réaumur with his experiments, and who rewarded the scientist for his work with an outsized pen- sion. At the same time, the Regent was a major patron of rococo painters and craftsmen, spending a fortune redecorating the Palais Royal between 1715 and 1723. To put his ideas into practice, Réaumur set up a shop and foundry in a lavish apartment near the Palais Royal. The cast-iron objects that he sold there during the 1720s received a glowing review in the Mercure de France, alongside reviews of the ornamental cut-outs that peaked in popularity during the same decade. The mode of production of those prints resembles that of Réaumur’s cast-iron bannisters and belt buckles. Despite their elaborate appearance, the cut-outs and the buckles could be manufactured in large quantities—the cut-outs by printing press and the buckles with a mould. Neither the press nor the mould were innovative technologies; the novelty lay in using them to make large numbers of cheap copies of expensive luxury goods.15 The production of beautiful imitations was also the aim of Réaumur’s prolonged investigation into porcelain. The only porcelain produced in France at the time was pâte tendre, a substance that was softer than Asian porcelain and less resistant to heat. Réaumur labored for many years to produce “French porcelain that is as beautiful [belle] and as affordable [bon marché] as that from China.” The quality of his porcelain, its beauty, and its decorative possibil- ities were a recurring concern in three papers that Réaumur read to the Academy in 1727, 1729, and 1739. He developed tests for measuring the quality of a porcelain based on its resistance to heat and the ﬁneness of its grains. He implied that the beauty of porcelain was his main motivation for studying the material, and he worked to show that his own creations were comparable in beauty to the Chinese original. He commented on the process of painting

15 For the Regent’s support, see Réaumur, Art de convertir, 259 (Cairo), 10, 11, 171; for the regent’s redecoration, Scott, Rococo Interior,147–152, 185–186; Kimball, Creation of Rococo, 121–130; for Réaumur’s shop, Mary Terrall, Catching Nature in the Act (Chicago, 2014), 45–47; Daniel Bontemps and Catherine Prade, “Un magasin parisien d’ouvrages en fonte de fer ornée au XVIIIe siècle: une réussite méconnue de Réaumur,” Bulletin de la Société de l’histoire de Paris et de l’Ile-de-France, CXVIII (1991), 215–261; for Mercure de France, Laing, “Ornamental Engravings,” 117.

Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/JINH_a_01162 by guest on 28 September 2021 STYLE AND SUBSTANCE IN ROCOCO SCIENCE | 371 and gilding porcelain, and he recommended his porcelain made from glass bottles on the grounds that surface colors could be added easily as part of the heating process. As in his treatise about iron and steel, Réaumur thanked the Regent for supplying the raw materials for his experiments, especially the talcs and flints that he substituted for the two main ingredients (kaolin and petuntse)inChineseporce- lain. Réaumur displayed a similar combination of commercial, aesthetic, and scientific intelligence in his studies of precious stones, fake pearls, silk garments, gold thread, and purple dyes.16 Réaumur was soon joined in these studies by Dufay, a soldier and aristocrat who served the Academy from 1723 to his death in 1739. To historians of chemistry and quality control, Dufay is known as the author of a new set of test procedures for distinguishing fast dyes from fugitive ones. To historians of textiles and global trade, he was the author of an early and influential account of the procedure used by indigenous artisans in India to apply dyes to cotton fab- rics. To his biographers, his involvement in textile dyes in the 1730s was a by-product of the experimental prowess that he had displayed in domains apparently unconnected to the decorative arts, such as electricity and luminescence. New research, however, shows that Dufay had been heavily engaged in the decorative arts even before he entered the Academy in 1723.17

16 For standard accounts of Réaumur’s research into porcelain, see Guerlac, “French Ante- cedents,” 84; Jean Torlais, Un esprit encyclopédique en dehors de L’Encyclopédie: Réaumur, d’après des documents inédits (Paris, 1961), 93–105. Réaumur, “Idée générale des differentes manières de faire la porcelaine; & quelques sont les véritables matiéres de celle de la Chine,” MAS (1727), 202 (“French porcelain”), 187 (quality), 186 (beauty), 199 (regent); idem, “Second Mémoire sur la Porcelaine,” ibid. (1729), 328, 339–340 (quality), 332 (beauty), 201 (painting and gilding), 329 (Regent); idem, “Art de faire une nouvelle espece de Porcelaine,” ibid. (1739), 375–378 (quality and beauty), 379 (colors); idem, “Découverte d’une nouvelle teinture de pourpre,” ibid. (1711), 166–196; idem, “Mémoire sur la matiere qui colore les perles fausses,” ibid. (1716), 229–244; idem, “Examen de la soye des araignées,” ibid. (1710), 386–408; idem, “Expériences et reflexions sur la prodigieuse ductilité de diverses matiéres,” ibid. (1713), 199–220; for Réaumur and precious stones, Bycroft, “Gems and the New Science: Craft, Commerce and Classification in Early Modern Europe,” unpub. ms. (Univ. of Warwick, 2017). 17 For the standard accounts of Dufay’s life and work, see Pierre Brunet, “L’oeuvre scientifique de Charles François du Fay,” Petrus Nonius, III (1940), 77–95; John Heilbron, “Dufay, Charles- François de Cisternay,” in Charles C. Gillispie (ed.), Dictionary of ScientificBiography(New York, 1970–1980), IV, 214–217; Bycroft, “Physics and Natural History in the Eighteenth Century: The Case of Charles Dufay,” unpub. Ph.D. diss. (Univ. of Cambridge, 2013); for chemistry and quality control, Guerlac, “French Antecedents,” 78–80; John J. Beer, “Eighteenth-Century Theories on the Process of Dyeing,” Isis, LI (1960), 23–25; Agusti Nieto-Galan, Colouring Textiles: A History of Natural Dyestuffs in Industrial Europe (London, 2001), 94–95; for textiles and global trade, Felicia

Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/JINH_a_01162 by guest on 28 September 2021 372 | MICHAEL BYCROFT That year marked the publication of Traité des vernis, a French translation of a treatise about Asian varnish that had first appeared in Florence three years earlier. The Italian version, written by the nat- uralist Filippo Buonanni, contained recipes for imitating Asian lacquer with European ingredients. The translation has usually been attributed to the writer and collector Antoine-Joseph Dezallier d’Argenville. A comparison between the text of the treatise and Fontenelle’s éloge of Dufay, as well as the discovery of a draft of the treatise in Dufay’s hand, show beyond doubt that the translator was Dufay rather than Argenville. A close study of the Traité des vernis, especially its eighty-six footnotes, shows that Dufay tested and augmented many of Buonanni’s recipes, and that he read many of the treatises that Buonanni cited, including such artists’ manuals as Abraham Bosse’s etching manual, Traité de manières de graver en taille-douce (1645). Dufay’s footnotes also show that he spoke to painters in Italy about the varnisher’s art, learning, for example, the meaning of the term acqua di rasa and a method for determin- ing the heat of linseed oil. Dufay’s interest in varnish went well beyond the production of the raw material. One of his footnotes was a detailed description of how to apply gold leaf to a varnished surface, most impressively to red varnish. Other footnotes mention varnished objects that Dufay noticed in Rome—streetlamps, locks of watch boxes, etc. Given the analogies between Dufay’s studies of Chinese varnish and Réaumur’s contemporaneous study of Asian porcelain, it is no surprise that Réaumur was the academician most closely involved in guiding Dufay into the Academy in 1723.18 Dufay continued to experiment with decorative materials after entering the Academy. His most substantial project in this area, aside from his later work with textile dyes, was an attempt to intro- duce artificial colors into such hard stones as agate, marble, and carnelian. In doing so, he tailored his recipes to contemporaneous trends in collecting and interior decoration. He dyed agate to re- semble the figured stones that were “entre les mains de toute le monde”

Gottmann, Global Trade, Smuggling, and the Making of Economic Liberalism (New York, 2016), 119–120, and references therein; for experimental prowess, Fontenelle, “Eloge de Du Fay,” Histoire de l’Académie Royale des Sciences (1739), 76. 18 This paragraph is based on Bycroft, “What Difference Does a Translation Make? The Traité des vernis (1723) in the Career of Charles Dufay,” in Sietske Fransen, Niall Hodson, and Karl A. E. Enenkel (eds.), Translating Early Modern Science (New York, 2017), 66–90.

Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/JINH_a_01162 by guest on 28 September 2021 STYLE AND SUBSTANCE IN ROCOCO SCIENCE | 373 and that Argenville would soon illustrate in his best-selling works on the natural history of shells and stones. He explained how to add a white stain to a piece of carnelian, how to add shading to the stain, and how to make lines on the stone that were sufficiently fine to allow the artist to draw miniature portraits. Dufay worked on a larger scale in his study of colored marble, in which he applied his procedures to the manufacture of tabletops and mantlepieces. One of his colored tabletops found its way into the workshop of a Parisian marbler, where it was discovered twenty years later by the connoisseur and archaeologist Anne Claude Philippe, Comte de Caylus.19 Dufay’s description of how to etch fine lines into the surface of marble was a self-conscious response to a new trend in interior decoration: “For several years now,” he wrote, “we have seen tables and chimneys of white marble decorated with very delicate sculptures and that seem to be the result of great labor.” He was probably referring to the transition, well-documented by art historians, from the fireplaces and chimney pieces of the reign of Louis XIV to those of the Regency period and the early reign of Louis XV. In the latter decades of the seventeenth century, mantlepieces tended to be large, high, rectangular, and sparsely decorated. In the early decades of the eighteenth century, they became low, curvaceous, and ornate, and were increasingly made of marble (see Figure 3).20 Dufay was sensitive to these developments in the decorative arts because he was an active participant in the Parisian art world. He valued decoration for its own sake—“il avait beaucoup de goût pour les choses de pur agrément,” as Fontenelle put it—and he developed a taste for antiquities during a ten-month study of Rome’s ruins in 1721/2. Both of these interests are manifest in an obscure thirty-page manuscript entitled “Sur l’origine de la peinture,” now housed in the archives of the Paris Academy of Sciences. In this

19 Dufay, “Mémoire sur la teinture et la dissolution de plusieurs especes de pierres,” Histoire de l’Académie Royale des Sciences (1728), 63 (tables and chimneys), 66 (“entre les mains”); idem, “Second mémoire sur la teinture des pierres,” ibid. (1732), 175–179 (portraits); Argenville, Oryctologie (Paris, 1755), 169–170 (pl. 5), 238–239 (pl. 10); for Dufay’s table, Anne Claude Philippe Comte de Caylus, “Sur un moyen d’incorporer la couleur dans le marbre, et de ﬁxer le trait,” Histoire de l’Académie des Inscriptions et Belle-Lettre (1758), 304. 20 Dufay, “Teinture et dissolution,” 63; Kimball, Rococo Decorative Style,65–69, 118 (rococo ﬁreplaces).

Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/JINH_a_01162 by guest on 28 September 2021 374 | MICHAEL BYCROFT Fig.3 Marble Fireplace Dating from c. 1730–1740

SOURCE John Whitehead, The French Interior in the Eighteenth Century (London, 1993), 110.

work, Dufay traced the history of painting from ancient times to the present, paying particular attention to practical techniques (wax painting, for instance), to periods when the general public acquired a taste (“prit gout”) for painting, and to the virtuosity of connoisseurs who could identify the author of a painting by sight alone (“a la seule inspection”). Dufay praised the “great beauty” of mosaics that he had seen in Rome, noting that a recently excavated painting exhibited a “taste entirely similar to those that we know today.” At the end of the manuscript, he revealed that he had himself unearthed an ancient fresco in Rome, soon to be analysed in the pages of the Académie Royale des Inscriptions et Belles-Lettres.21 The travels of this fresco exemplify Dufay’s connections to major art patrons of the day. After Dufay discovered the object, Armand Gaston de Rohan took it to Paris and gave it to the Regent. As noted above, the Regent was a patron of Réaumur and various

21 Fontenelle, “Eloge,” 75 (ruins), 79 (goût); “Sur l’origine de la peinture,” Dufay dossier, in folder entitled “Donner à l’abbé Nollet,” Archives de l’Académie Royale des Sciences; Claude Gros de Boze, “Sur un morceau de peinture à fresque, apporté de Rome,” Histoire de l’Académie des Inscriptions et Belle-Lettres, III (1718–1725), 446–451.

Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/JINH_a_01162 by guest on 28 September 2021 STYLE AND SUBSTANCE IN ROCOCO SCIENCE | 375 rococo decorators. Rohan was a Cardinal (his main business in Rome was to elect a new pope), a priest to the royal household (he presided over the confirmation of Louis XV in 1722), a member of the Regent’s tight circle of advisors, an art lover, and a boyhood friend of Dufay’s father. He used his time in Rome to secure an important set of paintings for the Regent and to enrich his own collection with portraits of French kings. He employed Louis XIV’s sculptors and architects to renovate his château in Saverne after it was damaged by fire in 1709; a decade later, he undertook extensive work on the Palais Rohan in Strasbourg. Both of these redecorations have been identified retrospectively as exemplars of rococo style. Dufay cared for his dying father at the Saverne residence in 1723, when the re-decoration there was largely complete, and he may have visited the Palais Rohan during the 1730s.22 Dufay was involved with two other key figures who straddled the worlds of art and science in early eighteenth-century Paris— Louis-Henri, Duke of Bourbon, and Edme-François Gersaint. Louis-Henri was a grandson of Louis XIV, first minister of France between 1723 and 1726, and owner of a splendid chateau at Chantilly. Between 1718 and 1722, he redecorated the chateau in a flamboyant style that is now virtually synonymous with the rococo. From that period to the 1730s, he built a collection of natural rarities that Argenville considered one of Europe’s finest. Letters exchanged in the 1730s between Dufay and Sir Hans Sloane, the owner of a vast collection in London that later formed the core of the British Museum, indicate that Dufay helped to fill the duke’s cabinet. Dufay had visited the collections of both the duke and Sloane, advising each of them about which items would (and would not) be suitable to send to the other. He used the duke’s gems in his experiments and supported the duke’sattempts to manufacture painted cotton (and probably to make lacquer) at the duke’s workshops at Chantilly. Gersaint was an art dealer who sold rococo objects, such as Watteau paintings and ornamental engravings, at his boutique on the Pont Neuf. Dufay bought a set of

22 Claude Muller, Le siècle des Rohan: une dynastie de cardinaux en Alsace au XVIIIe siècle (Strasbourg, 2006), 59–62, 87–88; Dufay to Réaumur, May 31, 1723; July 13, 1723, “Lettres de Dufay à Réaumur,” in Correspondance historique et archaelogique, V (1898), 306–309; Catherine Grodecki, “La Résidence de Saverne sous les trois premiers cardinaux de Rohan,” in Alphonse Wollbrett (ed.), Le Château de Saverne (Saverny, 1969), 39–53; Jean-Daniel Ludmann, Le Palais Rohan de Strasbourg (Strasbourg, 1980); Hubula, Baroque and Rococo,167.

Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/JINH_a_01162 by guest on 28 September 2021 376 | MICHAEL BYCROFT shells at Gersaint’s ﬁrst public auction of natural curiosities in 1736. Soon afterward, he wrote to Sloane that Gersaint, “un fort honneste homme, tres connoisseur,” was about to visit London to “établir des cor- respondences pour son commerce.” Dufay greased the wheels of exchange between dealers, collectors, artisans, and entrepreneurs whom we now associate with the rococo movement.23

SUBSTANCES IN SCIENCE Showing that a scientist studied the decorative arts is one thing; showing that the arts shaped his science is another; and showing that the rococo elements of those arts shaped his science is different again. An experiment by Dufay, described in a paper published in 1734, illustrates these distinctions. When Dufay found that a glass tube (when electriﬁed) and a piece of gum copal (when electriﬁed) had opposite effects on the same piece of gold leaf, he concluded that electricity was comprised of two species, thereby anticipating Benjamin Franklin’s distinction between “positive” and “negative” electricity. Two of the materials in the experiment had appeared in Dufay’s translation of the Traité des vernis. Gum copal was one of the ingredients in Buonanni’s main recipe for European varnish, and gold leaf was the subject of one of Dufay’s most elaborate footnotes. This is surely a case of a decorative art shaping a piece of fundamental physics, but it is not an airtight case. First, there is no evidence that the glass tube owed anything to Dufay’s interest in the decorative arts. Second, there is something unsatisfying about the example of gold leaf and gum copal. Copal may have derived from Dufay’sstudyof lacquer, but the properties that made lacquer a rococo substance— its glossiness and its Oriental associations—were unrelated to the

23 For Chantilly and rococo, see Kimball, Decorative Style, 131; for the duke’scabinet, Dezallier, Lithologie et conchyliologie, 210–211; Gersaint, Catalogue raisonné,31;Sloaneto Dufay, Hans Sloane Collection, British Library (hereinafter referred to as “HS”)Ms.4068, May 23, 1737, f. 317; Jun 13, 1737, f. 326; Dufay to Sloane: June 13, 1737, HS Ms. 4055, f. 119; May 24, 1737, HS Ms. 4058, f. 271; Sloane to Dufay, July 25, 1737, HS Ms. 4068, f. 329; Grandjean de Fouchy, “Eloge de Sloane,” 319; Dufay to Sloane, August 18, 1737, HS Ms. 4055, f. 166; Paul Raymond Schwartz, “La Fabrique d’Indiennes du Duc de Bourbon (1692–1740) au Château de Chantilly,” Bulletin de la Société industrielle de Mulhouse, 722 (1966), 17–35; for the duke’s lacquer workshop, Forray-Carlier and Kopplin, Secrets de la laque française, 28; for Gersaint, Guillaume Glorieux, Al’enseigne de Gersaint: Edme-François Gersaint, marchand d’art sur le Pont Notre-Dame, 1694–1750 (Seyssel, 2002), 562, 470, 280–281; Dufay to Sloane, April 15, 1739, HS Ms. 4056, f. 76; Geoffroy to Sloane, April 18, 1739, HS Ms. 4056, f. 79.

Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/JINH_a_01162 by guest on 28 September 2021 STYLE AND SUBSTANCE IN ROCOCO SCIENCE | 377 property—ease of electrification—that made copal an effective material in the experiment. Réaumur’s study of shells provides a more satisfying example, revealing that the rococo properties of a substance had methodological significance for a scientist. Shells appealed to collectors like Argenville because of their “bizarre” and “extraordinary” forms, precisely the properties that interested Réaumur when he set out to explain their mode of formation: “It seems that she [nature] has taken pleasure in varying their shapes, structures, and colours,” he wrote at the beginning of an early paper on the topic. He was especially intrigued by the “varieté reguliere” of garden snails. The background color of their shells was variously white, lemon, yel- low, or some intermediate hue, overlain with stripes that followed the spiral form of the shell and thickened as they neared the open- ing of the shell. The stripes were black on some shells and brown or red on others. Some shells had five or six of these stripes and others only one; sometimes two stripes widened so much that they merged to form a single stripe. Réaumur did not dismiss these varieties as irrelevant or illusory; instead, he tried to explain them using his general theory of shell formation. According to this theory, animals construct their shells by secreting tiny particles of earth through pores in their sieve-like skin. Réaumur posited that the variety of colors in the shells was due to the variety of the shapes of the pores in their skin. Pores of different shapes admitted particles of different shapes, which in turn reflected rays of light of different colors. The match between the colors on the skin of snails, and the colors on their shells, seemed to confirm this hy- pothesis. The “irregularités” of shells were not only explicable but also a source of new evidence for the theory: The match between the shells and the skins was compelling because of, not in spite of, the irregular colors of each.24 Generalizing from the previous two paragraphs, although regularity was the aim of Dufay’s and Réaumur’s research, irregularity was one of their most important means to that end. The conclu- sions of Dufay’s eight ground-breaking papers about electricity refer to “principes invariables” and “loix exactes,” but the body of each paper is filled with “circonstances singulières,”“variétés,”“bizarreries,”

24 Réaumur, “De la formation et de l’accroissement des coquilles des animaux tant terrestes qu’aquatiques, soit de mer soit de riviere,” MAS (1709), 365, 379–382, 384–387.

Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/JINH_a_01162 by guest on 28 September 2021 378 | MICHAEL BYCROFT “merveilles,” and even “prodiges.” In most cases, Dufay’s response to these phenomena was to use them to advance his investigation. He used the contrary behavior of glass tubes and gum copal, a phenom- enon that flew in the face of past experience, to develop the principle that electricities of the same kind repel and electricities of the two different kinds attract. He used the “strange effects” discovered by experimenters to strengthen his principles, turning their strangeness to his advantage by recommending his theory of electricity for “the number of obscure and puzzling facts it clears up.” Far from dismissing irregularities, Dufay used them to dismiss regularities. “One can- not report too scrupulously the singular happenings in these experiments,” he wrote at the end of an especially exasperating series of experiments, “especially when they appear not to agree with the principles one is trying to establish.” Similar statements can be found in Dufay’s papers about magnetism, fire-resistant salamanders, sensitive plants, figured stones, and mock suns—phenomena that (with the exception of fire-resistant salamanders) Dufay accepted as real and studied with enthusiasm even though they were considered bizarre or inexplicable at the time.25 Dufay and Réaumur studied superficial phenomena as eagerly as they studied irregular ones. The stand-out example is Réaumur’s study of the manufacture of fake pearls. As Réaumur explained to the Academy in 1711, a pair of French artisans had recently discovered a way to imitate pearls that was convincing enough to confound even jewelers—indeed these imitations were so decep- tive that the shopkeepers of Paris petitioned the king to ban the new substance in order to protect the value of real pearls and to preserve the distinction between women of low birth (who wore fake pearls) and women of quality (who wore authentic ones). The new pearls were triply superficial: They resembled real pearls but were not so; they were made of hollow glass spheres coated with a thin layer of liquid known as “essence d’Orient”; and this liquid came not from the Orient but from the river Seine, where it dwelt in the scales of the bleak, a fish that was widespread in France and not at all exotic. The milky shimmer of this liquid was the main topic of Réaumur’s second paper about fake pearls, which he read

25 This paragraph is based on Bycroft, “Wonders in the Academy: The Value of Strange Facts in the Experimental Research of Charles Dufay,” Historical Studies in the Natural Sciences, XLIII (2013), 344–353.

Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/JINH_a_01162 by guest on 28 September 2021 STYLE AND SUBSTANCE IN ROCOCO SCIENCE | 379 to the Academy in 1716. On the basis of observations with a microscope, he concluded that the shimmer was due to tiny grains suspended in the liquid. Réaumur then drew a remarkable series of analogies between the shimmer of essence d’Orient, the iridescence of the bellies of live fish, the silvery sheen of insects’ legs, and the brilliant powder that covered the wings of butterflies. These phenomena, he argued, were the collective effect of thousands of tiny particles set against a background of solid color. He backed up this interpretation with analogies to artificial colors such as tapestries made of leather and red varnish, black enamels that become blue or white when pulverized, and diamonds that become transparent when ground.26 Dufay, too, showed an interest in the play of light and color on decorative substances, most obviously in his papers about the luminescence of precious stones. These papers also illustrate the role of decorative materials in another, deeper, form of superficiality for the sciences. Rather than seeking the first causes of things, as seventeenth-century natural philosophers had done, Réaumur and Dufay often had the more modest goal of organizing the facts within a specific domain. To use terms made famous by d’Alembert in the preliminary discourse of the Encyclopédie, they sought “principes” rather than causes in nature, and they favored the “esprit systématique” over the “esprit de système.” Dufay’sstudiesoflight and electricity are instructive because many of the “principes” therein were grounded in Dufay’s large collection of precious stones. Dufay showed (among other things) that many gems glow in the dark after being roasted, rubbed, or heated by the sun or a flame; that all gems attract light bodies after being rubbed then heated; and that gems can be divided into two classes according to the amount of rubbing and heating that is required before attraction occurs.27

26 Réaumur, “De l’art de faire des perles,” PV, May 23, 1711; Shopkeepers, T/1490/18, p. 846r., Archives Nationales; Mercure galant, Aug. 1686, 233–235; Martin Lister, A Journey to Paris in the Year 1698 (London, 1699), 142, 144; Réaumur, “Mémoire sur la matiere qui colore les perles fausses,” MAS (1716), 231–235, 240–243; idem, “Formation des coquilles,” 372–373; idem, “Description de l’art de faire des cuirs dorés,” Histoire de l’Académie Royale des Sciences (1714), 106; idem, “Expériences et reﬂexions sur la prodigieuse ductilité de diverses matiéres,” MAS (1713), 199–220. 27 For the preference for “principes” over “causes,” see Dufay, “Electricité et lumière,” 523; for “principes,”“esprit systématique,” and “esprit de système,” Jean le Rond d’Alembert, Discours préliminaire des éditeurs (Paris, 1751), vi–vii, xxxi.

Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/JINH_a_01162 by guest on 28 September 2021 380 | MICHAEL BYCROFT Dufay experimented on twenty-seven of the thirty-seven species of precious and semi-precious stone recognized by Argenville and other contemporary mineralogists. As is evident from his laboratory notes, Dufay procured these specimens from individuals who lent him precious stones (mainly diamonds) from their collections for his experiments on light and electricity. The collectors included not only members of the social elite (such as the duke of Bourbon) but also people of more modest means, such as the chemist Claude-Joseph Geoffroy. It is no coincidence that Dufay gathered his experimental objects at a time when precious stones— especially small, brilliant-cut diamonds—were a staple of interior decoration and a common accessory among legal professionals, merchants, and even artisans. In Dufay’s hands, brilliants became the stuff of the “esprit systématique.”28 Precious stones also crossed the divide between art and nature. They held clues to the properties of light and electricity, but they were also ripe for imitation. Dufay’s papers reveal the rich connections between art and nature even at a time when natural philosophers no longer ascribed imagination to nature. For Dufay, and for most of his learned contemporaries, the “figures” on rocks and stones that resembled people, landscapes, or human artifacts were the result of pure chance rather than the craftiness of nature. Yet Dufay insisted that scientists had much to learn from figures introduced into stones by artificial means: “That which deceives one can enlighten others, and allow them to probe more deeply into the mysteries of nature.”29 How can deception bring enlightenment? Dufay’s studies of lacquer and decorative stones, and Réaumur’s studies of pearls and porcelain, suggest several answers. First, because imitations derived from the manipulation of natural materials, they could shed light on the behavior of those materials. To color stones artificially was to study the natural properties of the stones so colored and of the acids and pigments used to color them; to study the production of fake pearls was to study the anatomy of the fish with which those pearls were made. Second, high-quality imitations were usually

28 For the popularity of diamonds, see Sedlmayr and Bauer, “Rococo,” 239; T/1490/18, 853v., Archives Nationales; for Dufay’s gem collection and experiments, Bycroft, “Physics and Natural History,” 108–114, 118–125. 29 Dufay, “Teinture et dissolution,” 50.

Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/JINH_a_01162 by guest on 28 September 2021 STYLE AND SUBSTANCE IN ROCOCO SCIENCE | 381 the outcome of a lengthy process of trial and error in which the experimenter tested numerous materials without the benefitof established theory to guide him. This process often led to rules of thumb that grouped different materials according to their behavior in the laboratory—for example, the rule that agates with natural veins are harder to dye than those without them. These two activities—trial-and-error experimentation and the discovery of the rules about the differential behavior of materials—were just as effective in the search for the laws of light and electricity as they were in the manufacture of marble fireplaces or the search for European substitutes for Oriental lacquer and porcelain. A finalanddeeperpointisthatDufayandRéaumurwere open to analogies between natural and artificial substances because they played down the role of imagination in the production of the former. For Dufay, artificially colored stones only appeared to be the result of many intelligent acts of creation. In reality, they were thereliableresultofafewsimpleprocedures:“Most of those [colored stones] whose singularity astonishes us are the fruit of very brief and easy labor.” Dufay boasted that his own procedures for coloring stones could be performed by “the least intelligent artisan.” Similarly, Réaumur sought procedures for making porcelain and cast iron that were as easy as possible to execute. Fontenelle, summarizing Réaumur’s treatise on iron and steel, went so far as to compare metal workers to machines, “automata adjusted for a cer- tain sequence of movements.”30 In the eyes of these scientists, intelligence and ingenuity were necessary for discovering technical procedures but not for execut- ing them. The fact that nature lacked intelligence and ingenuity was therefore no barrier to comparing the procedures of artisans to the workings of nature. Réaumur scorned the idea that a turquoise ring could protect its wearer from harm, but he had no qualms about comparing the natural process of creating the color of turquoise to the artist’s procedure of dissolving ink in water. Nordidhebalkatcomparingthecolorofafish’s belly to that of a tapestry; the genesis of minerals to the production of steel, porcelain, and enamel; and the spinning of silk by spiders to the extrusion of fine gold thread by goldsmiths. Nature was not crafty

30 Dufay, “Teinture et dissolution”, 50. 64; Fontenelle, “Idée de son livre sur le fer et l’acier,” Histoire de l’Académie royale des sciences (1722), 45; Réaumur, “Ductilité prodigieuse,” 206.

Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/JINH_a_01162 by guest on 28 September 2021 382 | MICHAEL BYCROFT for Dufay and Réaumur, but it was craft-like. Nature resembled the sort of craftsmen that Dufay had in mind when he defined “prestige” as “work that is of very easy execution but that seems at first sight to be of great difficulty and duration.” For Dufay and Réaumur, nature was the great prestigitator, continually achieving remarkable ends by simple means.31

The answer to the paradox posed at the start of this paper—why did two cultural movements as different as rococo art and Enlight- enment science flourish in the same time and place?—is that these two movements were not as different as they appear at first sight. Rococo art was characterized by irregularity, superficiality, and imitation; Enlightenment science had the same traits. Dufay and Réaumur aimed to describe nature in terms of simple and uni- versal rules—in terms of regularities—but in doing so, they exploited the varieties and oddities of nature—its irregularities. They sometimes sought their rules behind the surface appearances of things, but they also sought them in the surface of things, whether in the play of light and color or in the patterns that emerged from comparing the surfaces of many different bodies. They denied that nature possessed imagination or ingenuity in the manner of a human craftsman, but they believed that nature resembled a craftsman who used simple and reliable processes to achieve elaborate and bewildering effects. These stylistic affinities between art and science were not merely abstract or formal. They were anchored in a shared set of patrons (such as Philippe II and Cardinal Rohan), collaborators (such as Gersaint), aesthetic terms (such as ornement), and, above all, in a set of decorative substances that included brilliant-cut diamonds, imitation gems, European lacquer and porcelain, enamels, tapestries, dyestuffs, and steel and iron. These substances embodied the rococo style, whether by resembling something

31 For turquoise, see Réaumur, “Sur les Mines de Turquoises du Royaume,” Mémoires de l’Académie royale des sciences (1715), 174–202, 192–193 (ink), 199–200 (protective virtue). Silk and gold thread: Réaumur, “Ductilité prodigieuse.” Minerals compared to porcelain: Réaumur, “Nature et formation,” 257–264. Minerals compared to iron: ibid., 249–251, 262, 268–271; idem, Art de convertir, 338. Porcelain compared to steel, idem, “Nouvelle espèce de porcelaine,” 379–383; Smith, “Porcelain to Plutonism,” 322–323. Minerals compared to enamels: Réaumur, “Descrip- tion d’une mine de fer du pays de Foix; avec quelques reﬂexions sur la manière dont elle a été formée,” mas (1718), 141–142; Dufay, “Teinture des pierres,” 180–181.

Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/JINH_a_01162 by guest on 28 September 2021 STYLE AND SUBSTANCE IN ROCOCO SCIENCE | 383 they were not (imitation gems, European lacquer and porcelain, or cast iron worked like wrought iron), by creating a dazzling effect (the brilliance of diamonds, the sheen of porcelain and lacquer, or the iridescence of tapestries), or by lending themselves to sinuous and asymmetric forms (wrought iron, porcelain, shells, or figured stones). The rococo properties of these substances interested scientists at the Academy, both in their attempts to perfect the decorative arts and in their efforts to understand nature. Scientists and artists shared a style because they shared these substances. It remains to be seen whether this finding applies beyond the French rococo in the period from 1710 to 1740. In that time and place, the bonds between science, style, and substance were the result of three background conditions—the centrality of substances to the arts of the age, the Baconian view of scientific inquiry in which the workshop was an extension of the laboratory, and an aristocratic culture that placed great value on the fine and decorative arts. Whether the findings of this article are valid outside the French rococo depends on the presence of these three conditions. Nonetheless, the example of the French rococo carries a methodological lesson, namely, that interdisciplinary historians need not slight the disciplines that they bring together. Obvious as this prescription may seem, it goes against the grain of much recent historiography of art and science. The notion of style is a common target of historians of art who wish to merge art history with political, social, and cultural history. As suggested earlier, re- visionist histories of the rococo movement, properly understood, reinforce the notion of rococo style rather than discrediting it. In the same vein, this article places the rococo movement in its context, not by dismissing the stylistic notions of irregularity, superficiality, and imitation, but by extending these notions to the experimental sciences. A similar point holds for the historiography of science. The overall trend in the history of science during the last half-century has been to strengthen ties with history and loosen them with science. This trend was well underway in 1981, when Thackray reported that “historians of science appreciate the intellectual chal- lenge of science, but their methods, their questions, and their goals are those of historians.” This trend has persisted into the twenty- first century, as shown by several reviews published in this journal and by recent reflections on the state of the field by Daston and

Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/JINH_a_01162 by guest on 28 September 2021 384 | MICHAEL BYCROFT Jardine. This article goes against the grain, first, by showing the historical importance of interactions between different disciplines within science: The richness of rococo science was largely due to the permeable boundaries between physics, chemistry, and natural history in the Academy.32 A focus on science also makes room for what we may call “mainstream science.” Historians who connected science to the rococo usually focused on people (such as Gersaint and Argenville) and practices (such as connoisseurship and shell collecting) that an earlier generation of historians would have considered incidental to mainstream scientific development. Yet our understanding of rococo science becomes richer, not poorer, when we consider cano- nical disciplines such as physics and chemistry and scientists such as Dufay and Réaumur. Finally, this article owes much to histories of science written by modern scientists (especially Smith) and to those written about recent science (especially twentieth-century physics). These accounts are not part of the official historiography of eighteenth-century science, but they informed this article by emphasizing the importance of materials, as opposed to instruments, in experimental research. The concepts of present-day science, like the concept of style, have much to say to historians who are willing to listen.33

32 Arnold Thackray, “Science, Technology, and Medicine,” Journal of Interdisciplinary History, XII (1981), 314; Robert I. Rotberg and Theodore K. Rabb, “Interdisciplinary History,” ibid., I (1970) 3–4 (history of science “totally transformed in the last few decades”); reviews in ibid., XXXI (2000), 78; XXXVI (2005), 76; XXXVIII (2007), 95; XLI (2010), 142; for recent re- ﬂections, Daston, “Science Studies and the History of Science,” Critical Inquiry,XXXV(2009), 804–811; Nicholas Jardine, “Chalk to Cheese,” Times Literary Supplement, December 16, 2011. 33 A few other articles have also gone against the grain, including several contributions to KostasGavrogluandJurgenRenn(eds.),Positioning the History of Science (Boston, 2007); Hasok Chang, “Putting Science Back into the History of Science,” presidential address, British Society for the History of Science, the 24th International Congress for the History of Science, Technology, and Medicine, University of Manchester, July 22, 2013. See also Sandra Herbert’s praise for Martin Rudwick’s knowledge of present-day paleontology, Journal of Interdisciplinary History, XL (2010), 590. For materials in physics, see Joseph D. Martin, “What’s in a Name Change? Solid State Physics, Condensed Matter Physics, and Materials Science,” Physics in Perspective, XVII (2014), 3–32; idem and Michel Janssen, “Beyond the Crystal Maze: Twentieth- Century Physics from the Vantage Point of Solid-State Physics,” Historical Studies in the Natural Sciences, XLV (2015), 631–640; Cyril S. Smith, “Porcelain and Plutonism,” in Cecil J. Schneer (ed.), Toward a History of Geology: Proceedings of the New Hampshire Conference on the History of Geology (Cambridge, Mass., 1969), 317–338; idem, “Art, Technology, and Science: Notes on Their Historical Interaction,” Technology and Culture, XI (1970), 493–549.

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