• 1 The paper is based on Pautet, 2021. See also Bray, Hilaire-Pérez, 2016. Works in global history hav (...)
• 2 For some debates on technology, China and the great divergence, see Liu, Deng, 2009; Allen, 2010; P (...)
• 3 For impacts of China on European material culture, see Mau, 2007; Gerritsen, McDowall, 2012; Koppli (...)
• 4 For recent works, see for instance: McCabe, 2008; Rochebrune, 2014; Jacobsen, 2013, 2019; Millar, 2 (...)
• 5 Beyond Joseph Needham’s collection on Chinese science and technology, there has been a great deal o (...)
• 6 Alayrac-Fielding (ed.), 2017; Statman, 2023.

1“Technical transfers” are a central topic in the history of international exchanges and quite a commonplace one when one looks at how information on technology can serve as a resource to solve problems in various settings. But in the case of China, techniques have been somewhat absent from the recent historiography of early modern China-Europe exchanges,1 despite the Great Divergence debates2 or the key role that China played in European 18^th-century inventions.3 Yet historians and sinologists have long highlighted Chinese influence on European culture, arts, economics thought or philosophy, but the technical field is less frequently, and widely, studied.4 It is all the more surprising as Chinese techniques have been well studied by a long-standing historiography5 and as China was a central influence on the Enlightenment in Europe.6

• 7 Landry-Deron, 2001; Jami, 2008.
• 8 See for instance Coquery, 2015; Harris, 1998; Maitte, 2009. Techniques were also at the heart of St (...)
• 9 See Raveux, 2015; Hilaire-Pérez, 2002; McClellan, Regourd, 2011. Wu Huiyi has dedicated a specific (...)

2The scarcity of research on that subject is especially notable in the case of early modern France, which had placed great hopes in the connection established with China since the reign of Louis the xiv^th.7 The “Chinese taste” of French elites, the encouragement of industrial espionage or the recruitment of foreign workers by the French royal administration is well documented,8 and a recent historiography of techniques has gradually highlighted the role of global networks on French inventive practices.9 However, the collection of technical information on China – traces of which can be found in 18^th-century French dictionaries and encyclopaedias – remains little known, and its impact as a resource for the French industry to be studied.

• 10 Most of technical information that circulated from China to 18^th century France did not lead to maj (...)

3For that purpose, the article focuses on a case study: the circulation of a Chinese technical knowledge, which led to a rare illustration of the successful transfer of a significant technical improvement in France at the end of the century.10 This case is the history of an emergency. In 1793, the French navy was in a critical situation. At the height of the French Revolutionary Wars, the production of the lanterns used to light warships came to a standstill. Animal horn plates were used on board instead of glass plates in order to reduce the risk of breakage and therefore fire, but horn plates were mainly manufactured in England, and the war cut off the navy’s supply chain. The government asked a renowned scientist – Alexis-Marie de Rochon, known as Abbé Rochon (1741-1817), director of the observatory in the port of Brest – to fix the situation by setting up a manufacturing workshop of horn plates as quickly as possible. His research showed results in a few weeks, thanks to the mobilisation of a surprising resource from China: a forty-year-old academic memoir on the manufacture of Chinese luxury spherical lanterns.

• 11 Rochon gave two lectures at the Institut de France years after and explained the 1793 situation: se (...)
• 12 Rochon, 1812, p. 62. Translation: “couvrir les fanaux de combat et d’entrepont des vaisseaux de l’e (...)
• 13 Rochon, 1798, p. 673. Translation: “depuis l’époque de la guerre entre la république et l’Angleterr (...)

5The context of the war known as the First Coalition (1792-1797) increased the need to produce horn lantern on French national territory. In 1793, Alexis-Marie de Rochon was in Brest to set up a monetary establishment for the Minister of Finance.11 A representative of the Comité de salut public reported to him an alarming situation. André Jeanbon Saint-André (1749-1813), who commanded the officers of the royal army in Brest, told the famous astronomer and member of the Académie des sciences about a major shortage of horns to “cover the battle and steerage lanterns of the ships belonging to the squadron under the orders of Admiral Villaret.”12 Because the war had been going on since February 1793 with Great Britain “marine shops in the main ports had completely run out of lantern horns for making lanterns” (see Fig. 1).13

• 14 Diderot, D’Alembert, 1765, p. 277.
• 15 Dictionnaire de l’Académie française, 1696, p. 249 et p. 630.
• 16 Ibid., p. 630.
• 17 Chaoui-Derieux, Goret, 2018.
• 18 Diderot, 1800, p. 454-455, and Reculin, 2017, p. 30.

6Horn lanterns had been known for a long time in Europe. Based on Pliny the Elder and Plautus writings, Diderot and d’Alembert’s Encyclopédie dates their use back to Antiquity.14 The Dictionnaire de l’Académie française used the terms “lanterne à corne” or “lanterne de corne” to illustrate articles on “corne” and “lanterne” in its 1696 edition15 and defined lanterns as “a kind of utensil made of glass, horn, cloth or some other transparent material, in which the candle is kept so that the wind or rain does not extinguish it.”16 Horn was used in the Middle Ages to make types of lanterns with wooden frames, despite its gradual replacement by glass.17 Although evidence of the use of horn for lighting diminished in the 17^th century, traces of it can be found until the French Revolution. At the 1767 Salon, Denis Diderot (1713-1814) described a drawing by Pierre-Jacques de Loutherbourg (1740-1812) showing a “horn lantern suspended from a rafter of the carriage.”18

• 19 Gay, 1988, p. 55; Plouviez, 2013.
• 20 He wrote several travel records, see for instance Rochon, 1791.

7In the navy, all the lanterns, whatever their type (for the sterns of ships, for signals, battles, bunkers, muted lanterns for the master gunners, etc.), were manufactured in Brest, but based on imported materials. At the time, Amsterdam and Rotterdam were the hubs for many of the materials used by the French navy but horns adapted to the marine lanterns were generally manufactured in England.19 The urgency of the situation led Rochon to come under pressure from Jeanbon Saint-André to find a solution to replace imports from England, by establishing a horn factory in Brest. Rochon was in charge for several reasons: he was an expert scientist working for the Navy (he had been a naval astronomer since 1766 and had already carried out research on lanterns and lighthouses in 1785); he had strong connections with leading scientific networks (as early as 1767, he had been Jean-Dominique Cassini IV’s correspondent at the Académie des sciences); he had been traveling in Europe, North Africa and the Indian Ocean, and had come across many lighting technologies abroad.20 However, the naval astronomer had never set a foot in China.

• 21 See note 11.
• 22 Rochon, 1798, p. 673.

8Yet, according to two memoirs he would read years later at the Institut de France,21 Rochon rediscovered in 1793 a note concerning the manufacture of Chinese lantern horns22 in the documentation he had at his disposal. It was based on second-hand information, as he said it had been written during an ocean voyage he had made twenty years earlier in the Indian Ocean with the famous French administrator Pierre Poivre (1719-1786):

• 24 About Pierre Poivre, see Malleret, 1974; Buttoud, 2016.
• 25 Pautet, 2021, p. 489-502, and Pautet, 2023.
• 26 McClellan, Regourd, 2011, p. 327-329.

9Pierre Poivre was a key figure in the circulation of information between Asia and Europe at the time.24 Born into a family of shopkeepers in Lyon, he had stayed in Canton (Guangzhou) as a missionary in his twenties, before turning into a commercial agent and later a colonial administrator.25 Like many people of his generation, he had been fascinated by Indian and Chinese technologies and had built for decades a strong network with travellers from China from whom he had recorded a great deal of information on Chinese arts, crafts and industry. He was clearly one of the best connoisseurs of Chinese technology in the 18^th century and a key agent of the French geopolitical projection in Asia as royal administrator.26 When he became a member of the Académie des sciences, belles-lettres et arts in Lyon in 1759, Poivre enumerated a list of Chinese technical subjects which he intended to share with the academicians for the improvement of the arts:

• 28 In the 1760’s, he is a regular correspondent of the French Minister Henri-Léonard Bertin on Chinese (...)

10From the 1750’s onwards, Poivre contributed to the rising interest of the government and of the Académie for China.28 Poivre also had an influence on a broader scholarly and academic audience. Rochon was one of them.

• 29 Journal oeconomique, September 1756, p. 92-98.
• 30 Le Chéron d’Incarville, 1755.
• 31 About d’Incarville, see Byrne Curtis, 1997; Métailié, 2001, p. 805; Wang, 2018, p. 110-111; McClell (...)

11However, the note Rochon said he rediscovered in 1793 had not been written by Pierre Poivre himself. According to Rochon, Poivre had led him to the reading of a report that had been sent from China in the middle of the 18^th century to be published in 1755 in the Mémoires de mathématique et de physique, of the Académie royale des sciences, and in a shorter version in 1756 in the Journal Oeconomique.29 The academic memoir was entitled “Mémoire sur la manière singulière dont les Chinois soudent la Corne à lanternes”30 (“On the peculiar manner in which the Chinese weld lantern horn”). It was written by a French missionary who died in 1757, at the age of 50 in Beijing, and whom Poivre never met personally. But, for an inquisitive mind like Poivre’s, the religious man behind the memoir was very familiar because Pierre Le Chéron d’Incarville (1706-1757) was one of the most famous 18^th-century French missionaries in China, and a key intermediary between the French administration and the Imperial Court in Beijing.31

• 34 Rochon, 1812, p. 63. Translation: “les procédés des Chinois n’étoient connus ni de lui [ni] de ses (...)
• 35 Rochon, 1798, p. 674.

14Rochon read with great attention the content of d’Incarville’s extensive memoir, which detailed all the steps carried out by the Chinese workers to manufacture large welded horn plates. As he explained in his lecture at the Institut de France, he found in the Chinese welding technique a great source of ideas to find a way of building a local production of military lanterns, beyond the slight research that had been carried out on horn plates manufacturing in the years before the French Revolution. Rochon compared d’Incarville’s memoir with French academic reports from the 1780’s and was stuck by the total absence of references to Chinese processes they contained. Commenting on a memorandum submitted to the Académie des sciences in 1786 by Henri Ganeau, an ivory worker from Beauvais who had undertaken the manufacture of transparent horn tablets, Rochon wrote that “the Chinese processes were known neither to him nor to his commissioners, which is perhaps worthy of note.”34 He spent weeks trying to adapt the Chinese process to the constraints of the resources available in Brittany, while at the same time seeking to improve the process. Rochon’s attention was entirely focused on the question of how to manufacture transparent horn sheets on an industrial scale in order to start up a quick and large-scale production. Using the Chinese memoir as a basis, he carried out a large number of trials crossing the Chinese technique with European tools and implementing simplifications best suited to his needs, trying lamination tests with a machine used to manufacture tablets for the navy for instance.35

• 36 Standaert, 1991.
• 37 The greatness of Chinese technological culture served as a justification for the great evangelisati (...)
• 38 Berg, 1998; Berg et al., 2015.
• 39 Berg, 2002.

16Inquiries into Chinese industry had grown since the early 17^th century. Since the arrival of Mateo Ricci in China in Beijing in 1601, the largest agrarian empire in the world had only been accessible to a few churchmen authorized to live close to the imperial court.36 Catholic missionaries gradually turned technology into a measure of Chinese greatness during the 17^th century. Letters and books about China praised the Chinese architectural prodigies and its expertise in metallurgy, hydraulic engineering or coal mining.37 During the same period, trade between China and Europe grew significantly. The craze for Asian products became an incentive for the multiplication of local imitations (Chinese-style varnishes or Delft earthenware for instance) that spread in Europe with great success.38 Gradually, it became clear for mercantilists that China had technical resources that could compete with European production. A comparison of the techniques used in China with those of Europe in several common technological fields (textiles, ceramics, gums and varnishes, etc.) could foster the improvement of processes and qualities in domestic productions.39

• 40 Landry-Deron, 2001.
• 41 Lach, Van Kley, 1993, p. 135-144, and p. 168-199; Dermigny, 1964; Van Dyke, 2005.
• 42 Bibliothèque nationale de France, Paris, Naf. 22335, f^o 340-341, “Mélanges sur l’histoire d’Afrique (...)
• 43 Menegon, 2013.
• 44 Wu, 2013.
• 45 From 1716 onwards, the “Enquête du Régent” supervised by the scientist René-Antoine Ferchault de Ré (...)
• 46 Hilaire-Pérez, 2015.
• 47 John Kay’s introduction of the English flying shuttle for spinning cotton in 1747 was one of its ma (...)
• 48 See Montigny’s project in Boissonnade, 1914, p. 63-67. Translation: “faire transporter et amener ic (...)
• 49 Pautet, 2021, p. 170-187.

17Since Louis XIV, French governments had had a great interest in developing diplomatic relationships with China.40 A French catholic mission was supposed to challenge the Portuguese monopole on evangelisation and the rising expansion of British and Dutch East India companies by building a stronger relationship with the Chinese court, as China was still deeply closed to European colonial expansion in Asia.41 French missionaries succeeded in building a residence in Beijing, near to the Forbidden City, thanks to their savoir-faire in medicine, astronomy or craftsmanship. Because of the French authorities’ interest in Chinese techniques, missionaries were asked to answer questionnaires for the Académie des sciences containing questions on agriculture, canals and manufacturing processes.42 Given the turbulent context of the Chinese rites controversy,43 it was only in the 1710’s-1720’s that crucial technical information was sent to France about one of the more speculated Chinese manufacturing technique thanks to information the Jesuit missionary François-Xavier Dentrecolles (1664-1741) collected from Christian workers in the Jiangxi province: porcelain making.44 The publication of his letters in 1717 and 1724 coincided with a revival of technological surveys in France on the behalf of the Académie45 and an increasing emphasis on technology and innovation as the basis for economic prosperity, according to the economic thinking of the time.46 Daniel-Charles Trudaine (1703-1769), Director of Commerce from 1749 onwards, made the improvement of techniques a central focus of the French administration, by ordering transfers of skills from abroad.47 In the 1750s, for instance, Jean-Charles-Philibert Trudaine de Montigny (1733-1777), a relative of Daniel Trudaine, drew up a “Project to improve the factories of France,” in which he proposed the idea of “transporting and bringing to France by the ships of the Compagnie des Indes some twenty Indian workers, some free, others slaves, all educated and well practised in the various parts of the work of silks and cottons, but mainly in the work of silks.”48 After 1720, the collaboration of French missionaries in China – who expected increasing financial support from the government – and the royal administration to collect technical information in China was reinforced.49

• 50 Ibid., p. 187-207.
• 51 Le Chéron d’Incarville, 1760, p. 139. Translation: “M. le Contrôleur général me demande, 1.^o Ce qu’ (...)
• 52 Letter from d’Incarville to Father Fiteau, Beijing, October 13^th 1754, quoted in Dehergne, 1965, p. (...)
• 53 Ibid., p. 293.
• 54 Thuillier, Birembaut, 1966, note 5, p. 363.

18Pierre Le Chéron d’Incarville was the key element of this machine after 1740. The missionary, trained as a botanist and glassmaker, had been approached by Parisian naturalist networks before his departure, and had been gradually asked by the administration to join the worldwide survey system intended by Daniel Trudaine and the Comptroller General of Finances Machault d’Arnouville (1701-1794).50 In one of his memoirs, the missionary reported: “Mr. Comptroller General asks me, 1.^o What can be substituted for Chinese varnish, 2.^o how to apply it and make it hard.”51 He also wrote to one of his colleagues: “I must send a report on cotton, which the Comptroller General has asked me to write. […] I have material for other reports, such as on how to raise silkworms to get more profit from it; idem on dyes.”52 With the support of the ships of the French East India Company, d’Incarville sent memoirs, machines and tools to Paris and Versailles. He wrote a twenty-five-chapter long memoir on cotton cloth factories in China in which he described the tools and the processes employed by the Chinese.53 The brief received by Trudaine was shared with the experts mobilised by the administration, like Jean Hellot, a factory inspector and expert in dying techniques. Hellot who was working for the Vincennes porcelain factory, as well, also consulted a note from d’Incarville on the processes used in the preparation of blue glaze for Chinese porcelain wares.54

• 55 Pautet, 2021, p. 187-207.

19D’Incarville thus provided surveys on paper manufacture, varnishes, cotton, silk or fireworks for years, as a correspondent of the Académie des sciences and of the French authorities.55 If Rochon got access to information about China while he faced his horn manufacturing issue, it was because d’Incarville had been at the heart of a worldwide network of agents working for the government in order to improve the quality of French manufactures in the middle of the 18^th century.

• 56 About Bertin, see Finlay, 2020, or Statman, 2023.
• 57 Dehergne, 1965.
• 58 See Beaurepaire, p. 455-459, and Fabre, 2011.
• 59 Letter from Bertin, Compiègne, June 30^th 1764, Ms 1521, f^o 36, Paris, Bibliothèque de l’Institut de (...)
• 60 Pautet, 2021, p. 295-339.
• 61 Letter from Father Benoist to Bertin, Beijing, November 16^th 1773, quoted in Cordier, 1917, p. 341. (...)

21It is thanks to a minister of Louis XV, Henri Bertin (1720-1792), that a major enterprise of accumulation of Chinese technical knowledge grew after 1760. Bertin was a Secretary of State in charge of mines, manufactures and agriculture, who had a great career in the French administration until the 1780’s.56 In 1764, he met two young Chinese priests, Aloys Ko (1732-1795?) and Étienne Yang (1733-1798?), some of the very few Chinese sent to Europe in the 17^th century to complete their theological training.57 The abolishment of the Society of Jesus in 176258 let Ko and Yang in despair. Bertin agreed to take them under his protection and to send them back to China, on one condition: to turn the two Chinese men who spoke perfect French into intelligence officers to support his agricultural and manufacturing policy. He spared no expense to put them “in a position to give us insights into several areas in which the Chinese seem to excel.”59 With the help of Pierre Poivre or the famous economist Turgot (1727-1781), Bertin organised their training in the observation of industry by visiting over forty manufacturing sites, from large state-owned factories to mining sites and by taking drawing, chemistry and electricity lessons.60 The cost was huge: the government spent around 20,000 livres tournois. to support this project. Contrary to the kingdom’s domestic policy, Bertin ensured the financial, institutional and material support of the ex-Jesuits – the Society of Jesus was officially suppressed in 1773 – until his death, in order to serve “the State by trying to provide it with some knowledge that might be useful to the sciences and the arts.”61

• 62 “Instructions sur le commerce des Européens en Chine,” Microfilm 1, Mi 70-1, Bordeaux, Archives dép (...)
• 63 See for instance, Letter from Perronet to Bertin, December 29^th 1764, Ms 1526, f^o 47, Paris, Biblio (...)

22At the turn of the 1760s and 1770s, Bertin took the lead in an undertaking carried out in the name of “public utility,” to take advantage of the expertise of the Chinese in various sectors. He sent questionnaires on a regular basis on subjects that interested his ministry, like coal mining or porcelain manufactories, with the help of experts. Jean-Rodolphe Perronet (1708-1794), director of the École des ponts et chaussées, sent Bertin a series of “Clarifications that we would like to have on the canals and roads of China.” The Manufacture de Sèvres did the same for porcelain,62 as did Turgot, who was interested in ways to improve the French paper making industry.63

• 64 Letter from Bertin to Ko and Yang, January 18^th 1774, Ms 1522, f^o 53v-54r, Paris, Bibliothèque de l (...)
• 65 Mémoires concernant l’histoire, les sciences, les arts, les mœurs, les usages, &c. des Chinois (177 (...)

23For almost thirty years, Bertin centralised information sent from Beijing on gums, varnishes, metal alloys, greenhouses, borax, vitriol, coal, dyes with books, paintings, drawings, samples, tools and machines that he wanted to share with manufacturers, craftsmen, scientists and amateurs in France. His cabinet in Paris played the role of a repository of objects and machines that could be consulted.64 He also published over 14 years a famous public journal named Mémoires concernant les Chinois in which he displayed most of the letters and reports he had received to make them available to a broader audience.65

• 66 Berg, 2006; Andrade, 2021.
• 67 Charpentier de Cossigny, 1798. His list of techniques was about the manufacture of gunpowder used i (...)

24Bertin died in exile during the French Revolution and thereafter, the French mission in Beijing shrank dramatically. However, the reputation of Chinese technology was still alive in many minds in France, even if it would be challenged by the publication of books from the embassies of Great Britain and Holland in China during the 1790s.66 In 1796, for instance, a French engineer named Charpentier de Cossigny (1736-1809) listed forty-three processes that still needed to be better understood or transposed to Europe in a book in which he dedicated a chapter to Chinese techniques.67

• 68 Davids, 2015.

25As a conclusion, if China happened to be a resource for someone like Rochon in the 1790s, it was not accidental or due to the fact he had been advised by Pierre Poivre. It was because the whole French imperial machine,68 especially during the reigns of Louis XV (1715-1774) and Louis XVI (1774-1792), had turned China into a means of strengthening its economic and industrial power in the competition between European powers. Many people in the royal administration and scientific circles looked for information from China to answer technical problems they faced.

• 69 Encyclopédie méthodique, 1789, p. 756-757.
• 70 Golvers, 2019.

27As a 18^th-century scholar, Rochon had tried to read everything that had been published on horn techniques, but found barely anything. The Encyclopédie did not say much on the subject: it confined itself to evoking the ancient and mythical English origins of the invention of horn lantern manufacture. The Encyclopédie méthodique was more eloquent, but its knowledge was confined to a sub-notice devoted to the welding techniques used in tin smithing in general. Those few paragraphs were based on a paper published in the “Journal économique du mois de septembre 1756.” That paper was d’Incarville’s memoir that had been republished after its first publication in 1755 by the Académie.69 In other words, in the absence of abundant literature on the manufacture of horn lanterns, the writings of the missionary in China had become a reference text on the topic during the second half of the eighteenth century. D’Incarville himself reported in the 1750s that he had found no memoirs or works on the subject when he began his investigations, although he had in Beijing a rather good library containing most of the academic knowledge of his time.70 In the second half of the 18^th century, the only text that could provide Rochon with an extensive and detailed explanation on how to make horn lanterns was d’Incarville’s.

• 71 Hilaire-Pérez et al., 2017.
• 72 Millar, 2007; Schaffer et al., 2009.
• 73 May-bo Ching, 2017.
• 74 For an inventory of Chinese travellers in France and in England, see Pautet, 2021, chapter 3.
• 75 Menegon, 2019.
• 76 For example, the careful examination of a Chinese loom sent to Bertin by experts commissioned by th (...)

28Even in the 18^th century, skills were still mostly learnt inside workshops, and were based on little codification of knowledge, often protected by a culture of secrecy.71 Although the Dictionnaire des arts et métiers sought to improve the way in which techniques were written down, many fields still escaped strict codification. On the other hand, the particular nature of the Chinese migratory context was a powerful incentive to transform the Beijing missionaries into “brokers of knowledge” on the basis of written reports.72 At the time, from a strictly legal point of view, Chinese people were not allowed to leave China or to work for a foreign government.73 There are very few Chinese craftsmen who succeeded in visiting Europe, and yet it was not accepted by Chinese authorities.74 On the other hand, from the 1720s onwards, only missionaries recognised as useful to the imperial court were allowed to remain in China, under the close supervision of the authorities in Beijing.75 Most of the European clerics who passed through China remained there until their death, without returning to Europe, potentially endowed with skills acquired on the other side of the world: they emigrated and never returned, and thus played a smaller part in the transmission of tacit knowledge than in the codification of knowledge observed in China.76

• 77 Bray et al. (eds.), 2007.
• 78 Wu, 2017.

29Under those conditions, the only way to transfer technical knowledge to Europe was to write it down. Sometimes, codification was based on texts already written by Chinese scholars because China had a great tradition of technical literature.77 French Jesuits used their ability to read Chinese in order to translate books and notes found in Beijing libraries.78 They also took advantage of their connections with Chinese literati or converted workers and of their own position in imperial workshops to collect information. D’Incarville had his own strategy. He recruited directly Chinese craftsmen to work with him in order to describe with a high degree of precision every gesture they used.

• 79 Le Chéron d’Incarville, 1755, p. 350. Translation: “J’engage[ai] des ouvriers à venir travailler de (...)
• 80 Idem.
• 81 Le Chéron d’Incarville, 1760.

30D’Incarville is quite forthcoming about the way he happened to learn to build Chinese lanterns with horn. He wrote he had employed several workers in the French residence to teach him the techniques of welding horns. He said: “I hired workmen to come and work for me, so that I would be in a better position to write about this subject.”79 He did so with the funds provided by the Comptroller-General of Finances Philibert Orry (1689-1747) to investigate Chinese technologies for the royal government.80 He did the same with other investigations, like his research into the manufacture and application of Chinese varnishes.81 These workers were frequently depicted in illustrations accompanying his memoirs, which were produced by Chinese artists at his request (see Fig. 3).

• 82 Vérin, 2007; Hilaire-Pérez, 2020.
• 83 Le Chéron d’Incarville, 1755, p. 351.
• 84 Ibid., p. 357. Translation: “pour que M. de Jussieu voit s’il connoît l’arbre qui les produit.”
• 85 Ibid., p. 351. Translation: “quelques feuilles peintes, où seront représentées les différentes faço (...)

31In that sense, d’Incarville was close to the first technologists who started to categorise and classify technologies during the 18^th century.82 D’Incarville supplemented his memoirs with samples, as well as paintings and drawings made at his request to transcribe the operating chains into a visual register or to represent the tools described in the text in order to reduce the distance between the written word and the tacit knowledge reported. His memoir on horn lantern sent to the Académie included samples (“I am sending models”)83: extracts of horns at different stages of production, tools, or plant species because the polishing of the pieces involved the use of “tree leaves, known as nicoukin-yé.” D’Incarville sent extracts of that plant to the Académie “so that M. de Jussieu can see if he knows the tree that produces them,”84 referring to the famous French naturalist and expert Bernard de Jussieu (1699-1777). He also specified that he intended to send “some painted sheets later on, showing the different ways in which horn is used, from pulling it from the heads of goats or sheep to using it in lanterns.”85 These painted sheets reconstructing the production process of lanterns were partly engraved in eleven plates provided at the end of the memoir published in 1755, with comments by d’Incarville.

• 86 Archambault de Beaune, Hilaire-Pérez, Vermeir (eds.), 2017.
• 87 Le Chéron d’Incarville, 1755, p. 355. Translation: “de la même manière à peu près que nos relieurs (...)
• 88 Ibid., p. 352 and p. 353. Translation: “une espèce de petit tranchet que j’enverrai” and “j’enverr (...)

32The Beijing missionary did everything possible to ensure that the technique could be understood in Europe. The manufacturing process was described step-by-step, with a great deal of details in terms of type of tool used, body position of the workers, necessary equipment and gesture to be performed. By dividing the production processes into sequences in his drawings, he summarized the gestures and tools used by Chinese workers with abstraction (“scrapes,” “polishes,” “softens,” “traces,” “heats,” “presses,” etc.). D’Incarville also used analogy to make it easier to understand Chinese techniques.86 The operation of correcting stains by scraping them off and adding a new piece of horn was likened to the action of bookbinders for instance (“in much the same way as our bookbinders put patches on calf bindings, making the edges of the patch & the hole very thin, going as they die”).87 The memoir also listed 17 different instruments used by Chinese workers (sharpeners, scissors, irons, mallets, hammers, pliers, saws, etc.), and at least two of them have been sent to France (“a sort of small trencher that I will send,” “I will send a model of press”88) and reproduced in an illustration published with the memoir (see Fig. 4).

• 89 Monnier, 2012, p. 64-65.

34The establishment of a lantern horn factory on the basis of a memoir describing a Chinese technique constitutes a very rare case of a so-called “transfer of technology” between China and Europe in the 18^th century. However, this notion still needs to be qualified. Rochon did not reproduce the technique read in d’Incarville’s memoir, but was inspired by it to implement his own process adapted to local constraints and techniques. He sent a report to Paris summarising the experiments he had carried out in Brest, which was favourably received by the authorities. A horn production unit based on Rochon’s observations was set up in Paris with the support of Claude Pierre Molard (1759-1837), a member of the Temporary Arts Commission, and some twenty people worked in the Paris workshop in 1793.89

• 91 About Chinese incentive for innovation, see Sigaut, 1989.

35Lantern horns made in Paris in the 1790s and later were different from those produced by the Chinese however: neither the material, nor the tools, nor the shape given to the objects were the same. But in a situation of emergency, d’Incarville’s memoir had served as an incentive to conceive an alternative technique to the manufacture of English suppliers. It acted a stimulus for innovation, more than a source of replication.91