Book Chapter
Reference
Testing microscopes between market and scientific strategies
RATCLIFF, Marc
Abstract
This paper claims that the testing of microscopes during the eighteenth century reveals specific types of interaction between makers and users and links between scientific and economic interests. Basic procedures for the comparison and test of microscopes existed already in the Enlightenment although many historians thought that these were invented during the nineteenth century. The paper discusses three kinds of tests, advertising, the admission of a microscope in the laboratory, and finally the selection test. The advertising test deals with the use of measures to advertise microscopes by makers and reveals the importance and variety of a growing competing market in Europe. Second, the admission test regards the procedure a scholar carried out in his lab when he received a new microscope.
This test concerns the standardisation of scientific instruments for the reproduction of experiments in the lab. Thirdly, scholars, and not makers, performed selection tests to choose the best microscope among several, showing the interconnection between market and scientific interests. These three tests illustrate three kinds of [...]
RATCLIFF, Marc. Testing microscopes between market and scientific strategies. In: D. Generali
& M.J. Ratcliff. From makers to users. Microscopes, Markets, and Scientific Practices in the Seventeenth and Eighteenth Centuries. Firenze : Leo S. Olschki Editore, 2007. p.
135-154
Available at:
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University of Geneva1
TESTING MICROSCOPES BETWEEN MARKET AND SCIENTIFIC STRATEGIES
La publicite´ est l’aˆme du commerce
Abstract– This paper claims that the testing of microscopes during the eight- eenth century reveals specific types of interaction between makers and users and links between scientific and economic interests. Basic procedures for the compar- ison and test of microscopes existed already in the Enlightenment although many historians thought that these were invented during the nineteenth century. The paper discusses three kinds of tests, advertising, the admission of a microscope in the laboratory, and finally the selection test. The advertising test deals with the use of measures to advertise microscopes by makers and reveals the impor- tance and variety of a growing competing market in Europe. Second, the admis- sion test regards the procedure a scholar carried out in his lab when he received a new microscope. This test concerns the standardisation of scientific instruments for the reproduction of experiments in the lab. Thirdly, scholars, and not makers, performed selection tests to choose the best microscope among several, showing the interconnection between market and scientific interests. These three tests illus- trate three kinds of relationships between the producers and consumers of these instruments: 1. shaping users, 2. converting makers’ products into scientific de- vices, and 3. rescuing makers.
1 This research was funded by the Swiss Science Foundation, no. 100011-105719. I am grateful to theBibliothe`que Publique et Universitaire, Geneva, to theAcade´mie des sciencesin Paris, to Marian Fournier and Paolo Brenni for their advices, and to Jutta Schickore for her ad- vices and editing of this paper. Figures 1, 2, 4, 5 and 6 are reproduced courtesy of Bibliothe`que Publique et Universitaire, Geneva; Figure 3 is courtesy Archives de l’Acade´mie des sciences, Paris.
THE MAKING OFUSERS: TESTING ANDADVERTISING MICROSCOPES
In December 1751, the Paris instrument maker Alexis Magny con- ducted a public comparison of his own microscope with other instruments in the presence of King Louis XV.2He reported on it in an article in the Journal e´conomiquewhere he demonstrated the optical and mechanical im- provements brought to his microscope. Scholars and amateurs were invited to compare their microscopes to his.3 A year later, in 1753, the test re- vealed the interest raised by the microscope among several savants, includ- ing the physician Claude-Nicolas Le Cat, and the academicians Antoine Ferchault de Re´aumur and Henry-Louis Duhamel du Monceau. Indeed, Magny published a table comparing the magnifications of several micro- scopes considered «to be the strongest»4 (Fig. 1).
Such a table calls for a first comment: where is ‘polite science’? Indeed, Magny ranked the microscopes not according toe´tiquette, but only accord- ing to their increasing magnifications, even if two of those microscopes be- longed to two kings.5 This test of several microscopes, among the first to be published in a table following those by Henry Baker,6provided a sub- ject for discussion between scholars and makers.
This table certainly helped to advertise the maker’s products. Dis- creetly Magny championed the microscopes by the British makers – he cit- ed Cuff – and claimed that his microscope could reach a magnification of about 1500 diameters.7At that time, the British makers sold more than ten
2 A. MAGNY,Me´moire pre´sente´ a` l’Acade´mie des Sciences, sur le microscope a` trois verres et universel, perfectionne´ dans leurs verres ainsi que dans leurs montures, «Journal Economique», January 1752, pp. 42-57: 56.
3 ID.,Me´moire sur le microscope..., cit., pp. 56-57.
4 ID.,Sur le microscope compose´, ou a` trois verres et universel, «Journal Economique», Au- gust 1753, pp. 46-79: 74.
5 When quoting this paper, M. DAUMAS(Les instruments scientifiques aux XVIIeet XVIIIe sie`cles, Paris, PUF, 1953, p. 350) stated that Magny made microscopes for the King, for Re´au- mur, Duhamel and the King of Poland, for there was a fashion of the microscope at the court.
But except a sentence where Magny (Me´moire sur le microscope..., cit., p. 45) stated he worked for the King, nowhere did he mention that he made the microscopes of the above table. Actually those were not his microscopes, because: 1. he compared them to his own microscope, with a magnifications of 1500 (!); 2. he cited Mr. Caulis and Mr. de Vedie`res for whom he made three microscopes; 3. according to Magny, Re´aumur had a microscope from Cuff. The attribution by Daumas spread later into auction catalogues.
6 H. BAKER,An Account of Mr. Leeuwenhoek’s Microscopes, «Philosophical Transactions», 41(458), 1740, pp. 503-519.
7 A. MAGNY,Me´moire sur le microscope..., cit., p. 50ff.
types of microscopes with advertising through leaflets and trade-cards.8 Magny wanted to compete with them, but he used a different style of ad- vertising. He published his pamphlet in theJournal e´conomique, among ar- ticles on the transport of wood, ship arrivals, agriculture, and prices of goods in Europe. Mainly read by an elite public,9Journal e´conomiquepub- lished monthly economic news and articles with a practical goal and set aside theoretical contributions.
8 See on that M. CRAWFORTH,Evidences from Trade Card for the Scientific Instrument Indus- try, «Annals of Science», 42, 1985, pp. 453-554.
9 S. BOTEIN-J. CENSER-H. RITVO,The Periodical Press in Eighteenth century English and French Society: A Cross-Cultural Approach, «Comparative Studies in History and Society», 23(3), 1981, pp. 464-490: 476-480. See also the suggestive paper from R. DARNTON,An Early Information Society: News and the Media in Eighteenth century Paris, «The American Historical Review», 105(1), 2000, pp. 1-35.
Fig. 1. Magny’s comparison of microscopes.
But how did his contemporaries perceive such a «test» by Magny? An answer to this question requires the understanding of the way scholars per- ceived instrument makers in the eighteenth century, including the role that cultural differences played. In the scholarly French context, a tacit rule urged scholars to avoid quoting makers and created an invisible constraint for microscope makers, contrasting with the resounding advertising by British instrument makers. Table 1 shows the amount of citations of micro- scope makers (from now on MM) by scholars for each country, and their relative ratings (not counting leaflets).
TABLE1.Microscopes makers (MM) cited by scholars per country and language 1700-1800 n.MM/Country Number of citations ofMMfrom
Authors n G E I F H tot TOT % t/T t/n N %N/n
from G 38 55 22 1 2 4 83 750 11.1 2.2 180 20.6
E 20 1 26 3 30 370 8.1 1.5 98 20
I 19 3 34 13 6 2 57 250 22.8 3.2 88 20
F 9 1 1 9 11 530 2.1 1.1 114 8.1
H 3 2 3 3 7 138 5 – 30 10
S 3 1 2 3 87 3.4 – 40 7.5
Tot 95 62 88 18 17 9 191 2125 2.1 560 16.9
% heter. 11 71 – – – –
Explanations of the symbols used:
n Number of scholars per country who quoted one or moreMM
G, E, I, etc. German lands, England, Italy, France, Holland, Sweden tot Sum of the citations ofMM, per country
TOT Sum of the papers citing microscopes, per country
% t/T Ratio ofMMcited per paper citing microscopes, per country t/n Mean of the number of microscopes cited by authors, per country N Number of authors citing the microscope, per country
% heter. Frequency of makers cited by foreign scholars
Hyphens in the ratings columns mean that the amount of data is too small to be useful.
For example, the first line (German lands) reads as follows: 180 Ger- man-speaking authors wrote 750 papers, 38 out of these 180 authors cited 83 MM, among them 55 GermanMM, 22 EnglishMM, 1 ItalianMM, etc. 55 German MM does not mean that these were 55 different makers, because some of them were cited several times. This table shows cultural differ- ences between countries concerning the ways scholars and elite referred to makers. The French had indeed the smaller ratio ofMM cited per 100 papers (2.1), while the Italians (22.8) cited ten times the FrenchMM. Ger- man and English were approximately the same, with more or less 10% of
the papers quoting makers. The table also shows that British makers had developed an international, although very small, market that sold micro- scopes abroad: 11% of German MM were mentioned by non-Germans, while 71% of British MM were cited by non-British (last line).10Still, this 71% represents only 3.5% of all the microscope market in the Conti- nent...11
These cultural differences in citing practitioners must be taken into ac- count to understand the production and visibility of instruments, and to avoid the stereotypes separating British practitioners from French theore- ticians. The fact that scholars quoted many British makers does not mean that the Continent lacked instrument makers, but that the British pursued an international marketing policy that was less developed on the Continent.
If the French elite seldom referred to makers, this does not imply that there were fewer makers in France, but that the various countries were affected by strong differences in the management of marketing and visibility. The British aggressively applied a marketing policy, with a strong «faith in the machine»,12 along with a competing culture of advertisement13 that was not as developed in other countries. For instance, trade-cards did not exist in most countries on the Continent, especially those under catho- lic influence, and above all France, where advertising didnotbelong to the cultural habits of the market prior to the 1780s. While the British makers
10 For more on British makers and advertising, see A.N. DISNEY-C.F. HILL-W.E. WATSON
(eds.),Origin and Development of the Microscope, London, The Royal Microscopical Society, 1928; R.S. CLAY-T.H. COURT,The History of the Microscope Compiled from Original Instruments and Documents, London, Griffin, 1932; G.L’E. TURNER,Scientific Instruments and Experimental Philosophy 1550-1850, Variorum, 1990; J.R. MILLBURN,Adams of Fleet Street, Instrument Makers to King George III, Aldershot, Ashgate, 2000. On German makers and advertising see I. KEIL, Microscopes made in Augsburg(this volume); on Italian microscopes, see S. BEDINI,Seventeenth century Italian Compound Microscopes, «Physis», 5, 1963, pp. 383-422; J. BENNETT,Malpighi and the Microscope, in Marcello Malpighi Anatomist and Physician, edited by Domenico Bertoloni Meli, Firenze, Olschki, 1997, pp. 63-72; M. FAZZARI,Incredibili visioni: Roma e i microscopi alla fine del ’600(this volume), and A. LUALDI,Microscope makers in eigtheenth century northerm Italy(this volume); On Dutch makers, see P. DECLERCQ,Exporting Scientific Instruments around 1700, The Musschenbroek Documents in Marburg, «Tractrix», 3, 1991, pp. 79-120; ID.,At the sign of the Oriental Lamp. The Musschenbroek workshop in Leiden, 1660-1750, Rotterdam, Eras- mus Publishing, 1997; M. FOURNIER,Early microscopes. A Descriptive Catalogue, Leiden, Mu- seum Boerhaave, 2003.
11 2125-370 = 1755; 88-26 = 62; 62/17556100 = 3.5%.
12 L. STEWART,A Meaning for Machines: Modernity, Utility, and the Eighteenth century Brit- ish Public, «The Journal of Modern History», 70(2), 1998, pp. 259-294: 262.
13 See for instance on the British manufactures, M. CRASKE,Plan and Control: Design and the Competitive Spirit in Early and Mid-Eighteenth century England, «Journal of Design History», 12(3), 1999, pp. 187-216.
printed trade-cards to advertise their goods, publishing leaflets as well as loose sheets in London journals and newspapers, their French colleagues, in particular Nicolas Bion, Louis Joblot, Jean-Antoine Nollet, Marc Mi- touflet Thomin, or Claude-Simon Passemant, issued big treatises on mak- ing and using their instruments, thus combining educational and advertis- ing purposes. Only after 1776, when the French Minister Turgot endeavoured, without success, to abolish guilds, the French instrument makers adopted a new culture of advertising, which reproduced many of the British methods.14
It is in this economical context of concealed advertisement that one should understand Magny’s test. Although academicians attended his test, other makers saw it as an advertising campaign. Very clearly the test was just a showcase for selling instruments, thus breaking the corporation rules.
Indeed, contrary to other instrument makers who were forced to remain silent, Magny could afford his advertisement because the Duc de Chaulnes, a wealthy aristocrat and academic scholar greatly interested in technical ad- vances, patronized him. Magny obtained from the King the privilege of making his instruments; he established his workshop inside an abbey and remained undisturbed by the police of corporations.15In France, both the limited marketing culture of instrument makers and the juridical re- strictions from the guilds did not allow masters to advertise their products.
Public advertising was tolerated only for artisans or scholars with a privi- lege granted by the King, provided they would write scholarly treatises and mingle these with education. Both a scholar and an entrepreneur, ab- bot Nollet ran a workshop and wrote treatises of experimental physics where he could advertise his own instruments, including microscopes. This formula led to a successful international business.16
A year later, in 1754, Le Canu, a French maker of optical instruments in Rouen, published a paper against Magny in the same Journal e´conomi-
14 On Turgot’s impact on makers, see M. DAUMAS, Les instruments scientifiques..., cit., pp. 134-136. On reformations of the guilds, see L. VARDI,The Abolition of the Guilds during the French Revolution, «French Historical Studies», 15(4), 1988, pp. 704-717; and on the reac- tions by the guilds, especially by women, see J.G. COFFIN,Gender and the Guild Order: The Gar- ment Trades in Eighteenth century Paris, «The Journal of Economic History», 54(4), 1994, pp. 768-793.
15 M. DAUMAS,Les instruments scientifiques..., cit., p. 350.
16 See on that, J.-F. GAUVIN,Eighteenth century Entrepreneur: Abbot Nollet’s Instrument- Making Trade Seen Through his Correspondence with Etienne-Franc¸ois Dutour and Jean Jallabert,
«Bulletin of the Scientific Instrument Society», 57, 1998, pp. 21-25. See J.-A. NOLLET, Pro- gramme ou ide´e ge´ne´rale d’un cours de physique expe´rimentale, Paris, LeMercier, 1738.
que. A member of the Acade´mie des Sciences, Belles-Lettres et Arts of Rouen, Le Canu defined his target in the title, «An answer to a section of a paper on microscopes, printed in theJournal Economique, in August 1753».17He was unpleasantly surprised by the style adopted by his collea- gue, and took it as a disguised and misleading advertisement. Le Canu re- minded that regular advertising was «for public utility and not only for per- sonal interest».18 He was disturbed by the paper because Magny cited a
«Rouen microscope, compared in front of Le Cat», which in fact was the one made by Le Canu. At this point, he complained:
its magnifying power is said to be 240 times. Although this could seem a high mag- nification, it actually remains far below what I thought I could manage to build.19 Le Canu also seized the opportunity to advertise his instruments. He built instruments on request, with several prices, and took great care to ob- tain a sufficient brightness, a large field, and to keep suitable proportions for each instrument,20his workshop being just large enough to fill the great need of optical instruments. Moreover, in this technical duel, the fight was one-sided, for the body of Magny’s microscope was 7 inches long (+17 cm), against the 4 inches (+10 cm) of Le Canu’s... Thus Le Canu an- nounced a new 7 inch-long «comparative microscope», presented to the Rouen Academy in July 1754. The Academy chose an examination board to assess its magnifying power, and Le Canu published the certificate that confirmed the higher magnification of his microscope.21 If Le Canu stressed the unfair marketing strategy of his rival, he actually did the same, but in a more academic style, for the place for Magny’s comparison was his workshop, while that of Le Canu was held in the presence of experts of an academy.
17 LECANU,En re´ponse a` un article d’un me´moire sur les microscopes, imprime´ dans le Jour- nal e´conomique en Aouˆt 1753, «Journal Economique», 1754, pp. 37-43: 37.
18 ID.,Re´ponse a` un article..., cit., p. 37: he spoke of «l’utilite´ publique et non seulement pour l’inte´reˆt personnel».
19 Ivi, p. 38.
20 Ivi, p. 39.
21 Ivi, p. 42: «M. Le Canu, Opticien, membre de l’Acade´mie, ayant pre´sente´ le 27 juin a`
cette compagnie un microscope de sa fac¸on, et ayant demande´ des commissaires pour en consta- ter la puissance; Elle nomma a` cette intention M. le Bas, Pingre´, Le Cat, etc. Par le rapport que ces messieurs ont de´pose´ dans les registres le 4 Juillet, il demeure constant que le Microscope pre´sente´ a` l’Acade´mie lequel a 7 pouces 2 lignes de hauteur, grossit seize cent soixantes fois le diame`tre de l’objet, et qu’en l’allongeant encore de 9 lignes, il grossit 2200 fois, n’ayant toujours e´gard qu’au diame`tre».
This episode shows how the competition between makers in the public French marketplace took advantage of specific loci – workshops and aca- demies – where scholars and practitioners met. In order to legitimate their advertising, makers interacted with scholars, and borrowed academic stra- tegies that helped to conceal advertising. Magny’s paper was not a simple list of prices, or a trade-card, as in Holland or in London. By contrast with the British marketing style, direct advertising almost did not exist in France. And such a comparative test was a new and good rhetorical sample in the setting of the sophisticated French advertisement strategies.
TRANSFORMING THEMAKER’SGOODS: ADMITTINGMICROSCOPES IN THELAB
Certain scholars, but not makers, used another test for microscopes of which there remain traces in lab notes and correspondences. In February 1766, in Geneva, the professor of physics Horace-Be´ne´dict de Saussure who had experimented on fission in infusoria received a simple microscope from John Cuff. He wrote to Albrecht von Haller in March: «I recently re- ceived a good Microscope from England».22In his lab notes, he wrote:
After I received my simple microscope by Cuff, thanks to Mr Tollot, I com- pared it with my double from Scarlet and I found the latter always better than the former, even when I used the stronger magnification and fitted the tube to trans- form it into a double microscope. I think I shall carry on using the Scarlet, and use the Cuff only for particular observations that call for confirmation. I also found that the small spherules of my old pocket microscope were much stronger and showed an object much more distinct than the smaller lenses by Cuff. Thus, for observations with the simple microscope, one should try to use those lenses along with these by Cuff, and even prefer them to the latter.23
This lab note inscription helped Saussure to remember the specific function of the Cuff. It would be used to verify observations with the Scar- let; and the Cuff lenses were also complementary to those of the pocket microscope, once they were mounted. Therefore the admission of the Cuff in the lab changed its order in reorganizing the rank of the various micro- scopes. Yet, this order was not only to be found in the laboratory but equally
22 Saussure to Haller, 4 March 1766, inThe correspondence of Albrecht von Haller and Ho- race-Be´ne´dict de Saussure, edited by Otto Sonntag, Bern, Huber, 1991, p. 251.
23 Bibliothe`que Publique et Universitaire of Geneva, Ms Saus. 64Agenda des recherches.
in the mind of the scholars. To credit the newly arrived instrument with a specific function, the scholar managed a set of functional representations, which I call aninstrumental system. A new instrument joined an instrumen- tal system already in operation, thanks to a test for admission. In compar- ison with other instruments, the test evaluated its technical features and the kind of image it could produce. A new instrument required an examination so as to be eligible for a suitable place both in the laboratory and in the instrumental system.
The admission test also illustrates the demarcation of scientific activity from both popularisation of science and market production. Indeed, the scholar used it with a view to performing further observations, while mi- croscopes used for amusement neither needed any test or measure of their power, nor called for instrumental systems. The reason is that this test has a symmetrical pattern with respect to the experimental repetition on which so much has been said by historians and sociologists of sciences. The pat- tern of experimental repetition shows several scholars acting as various wit- nesses – and virtual witnesses – in order to establish the uniqueness of a phenomenon.24 In the admission test, there is a symmetrical design, for it supposes a variety of images of the same preparation due to the use of several instruments, synthesised by a single witness. Complementary thus to the experimental repetition of which it reverted the structure, the admis- sion test met the scientific need of controlling the image by switching in- struments and not witnesses.
On the other hand this test also opens up other possibilities. In the let- ter to Haller, Saussure added: «I wanted to have two of them [micro- scopes] in order to verify the most important facts by means of double ob- servations».25The test estimated the particular role each instrument played in the production of good images through the use of double – actually, at least triple-check. Indeed, Saussure considered that his four microscopes (Cuff, Scarlet, pocket, Nollet) balanced each other; they developed afunc- tional complementaritywhere each instrument played a specific role. Scho- lars knew that microscopes were far from being standardised. In order to compensate the various imperfections – chromatic aberration, poor grind- ing, sphericity – and the absence of standardisation that strongly hindered
24 S. SHAPIN-S. SCHAFFER,Leviathan and the Air-Pump, Hobbes, Boyle, and the Experimen- tal Life, Princeton, Princeton University Press, 1985, p. 59.
25 Saussure to Haller, 4 March 1766, inThe correspondence of Haller..., cit., p. 251.
the reproduction of observations, the strategy was to use several micro- scopes and lenses to secure a good image. To balance the lack of standard- isation, scholars did not multiply witnesses but instruments. They adapted the structure of the experimental repetition from the social to the instru- mental level. And indeed, from 1740 on, many of them declared the use of several microscopes and lenses used for their research (see Table 2).
TABLE2.Number of microscopes used by scholars, per country26
England German speaking countries
C.H 1703 3 Gmelin 1745 3 +
Miles 1741 all kinds Springsfeld 1752 2 +
Parsons 1745 3 + Ro¨sel 1755 3 +
Hill 1752 3 Remi 1756 2
Badcock 1746 2 Berguen 1757 3
Ellis 1755 2 + Delius 1766 3
Stiles 1765 2 Ledermu¨ller 1762 4 +
Hewson 1770 2 Ledermu¨ller 1764 2 +
Hewson 1773 2 Wrisberg 1765 2 +
Goeze 1773 3 +
Italy Meidinger 1777 2
Della Torre 1763 10 Koestlin 1780 2
Spallanzani 1765 2 + Gleichen 1781 4
Fontana 1766 2 + Anon. 1782 2
Targioni 1767 6 Goeze 1782 5
Bovi 1769 2 Bloch 1782 3
Roffredi 1769 3 +
Magni 1776 2 France
Mascagni 1783 3 Joblot 1718 2 +
Lupieri 1784 2 Duhamel 1732 2 +
Duhamel 1758 2 +
Geneva Dicquemare 1777 2 +
Bonnet 1745 2 + Mirbel 1801 4-5
Saussure 1762 2 Villars 1804 3
Saussure 1765 3
Vaucher 1798 2 + Holland
Trembley 1744 2 +
Sweden Luchtmans 1758 2
Geer 1749 2 + Lyonet 1762 2
This table shows that many important authors relied on functional complementarity for their microscopical observations, arranging together several instruments to perform a single function. Indeed what matters is
26 The + means the use of magnifying glasses.
not the instrumentper se, but the functions. When instruments were not standardised, a stable image was built on the basis of what was shared by different instruments, while with standardisation, each instrument em- bodied thesamefunction and made possible to expect a comparable repe- tition of the observations. This latterfunctional identity, a match between a function and one instrument opened the way to standardisation and was developed by makers from the 1830s onwards. Before that time, several in- struments frequently helped to build one single image out of several images taken from various microscopes that balanced each other, thus producing a clear image of an invisible body. And scholars acknowledged that the func- tions of simple and double microscopes were different.27
In the eighteenth century, certain scholars also wanted to make people believe that microscopes were standardised and adopted a rhetorical attitude toward functional identity. In 1749, in a well-known engraving, Buffon il- lustrated his research group using only one microscope (see Fig. 2).28 Such an engraving leads one to think that using one microscope for research was the standard. Indeed, in the second half of the century, other scholars – mainly German and British scholars – also claimed to use only one microscope. The advent of optical standardisation in the nineteenth century, of which we know so little, progressively eliminated the functional complementarity from instrumental practices. Since microscopes were standardised, each function corresponded to one instrument (and to one part of an instrument, such as various lenses in a microscope). For instance, around 1804, the Paris bota- nist Brisseau de Mirbel said that he used «four or five different microscopes»
for his investigations on plant physiology.29 Forty years later, in 1846, the French maker Lerebours recalled that since the 1820s scholars used only one microscope, although several parties discussed the issue:
Since that time, scholars and micrographs were divided in three factions: the first were exclusive supporters of simple microscopes, the second found nothing compar- able to the dioptrical horizontal microscope by Amici, and finally the last preferred the vertical microscopes improved with achromatic lens over any other system.30
27 P.VANMUSSCHENBROEK,Essai de physique, Leide, 1739, t. II, pp. 594-597. Trembley to Folkes, 12 April 1743: «Je me sers du Microscope double ou du Simple selon le besoin», Lon- don, Archives of the Royal Society, Ms 250, Fol 3, f. 52v.
28 G. LECLERC DEBUFFON,Histoire naturelle ge´ne´rale et particulie`re avec la description du cabinet du Roy, Paris, Imprimerie royale, 1749, t. 2, pp. 172-173.
29 C.F. MIRBEL,Traite´ d’anatomie et de physiologie ve´ge´tales, Paris, An 10 [1804], p. 50.
30 N.P. LEREBOURS,Instruction pratique sur les microscopes contenant la description des mi- croscopes achromatiques simplifie´s, Paris, Lerebours et Secre´tan, 1846, p. 12.
The period of 1820-30 signalled the extinction of the functional com- plementarity. From the eighteenth to the early nineteenth century, scholars changed their regime of observations. Historians of microscopy who be- lieve that only simple microscopes were useful before 184031think in terms of functional identity. But to understand eighteenth-century instrumental practices we need to think in terms of functional complementarity. It ap- pears that only the latter category is not anachronistic. As a sign of the times when scholars worked in the lab relying on functional complementar- ity, the admission test marked one of the scholarly boundaries of the
31 See B.J. FORD,Single Lens, The Story of the Simple Microscope, New York, Harper &
Row, 1985.
Fig. 2. Buffon’s research group using the microscope.
laboratory. This test manifests another relation between makers and users.
Thanks to it, users couldtransformthe artificial goods produced by makers into scientific instruments.
So on the one hand, certain makers used rhetorical tests to promote their instruments, in line with the quantifying spirit that inspired European scholarship from the middle of the century.32 On the Continent, certain makers used tables of technical measures as a new form of advertising mi- croscopes, as did Passemant, Magny and Le Canu.33Later in the century, many scholars would mention magnifications or publish tables of magnifi- cations in their papers. This attitude aimed at helping other scholars to re- peat their observations and does not really call for interaction with the ma- kers.34On the other hand, certain scholars used the admission test to turn the maker’s product into a scientific instrument, all while neglecting the rhetorical noise. Far from only trusting numbers, their goal was to focus on the production of stable and faithful microscopical images, and most of these tests of instruments remained unpublished. For instance, in 1747 the French academician Michel Adanson compared a simple micro- scope by Wilson to a microscope for opaque objects and to his own double microscope by George (Fig. 3).35He used a micrometric grid to compare the instruments.
RESCUING THE MAKERS: SELECTIVE TESTS OF MICROSCOPES
Yet, scholars used another version of the advertising test to highlight par- ticular microscopes, which they selected thanks to compared technical trials.
In London in 1740, Henry Baker, a close friend of John Cuff, ini- tiated this fashion while comparing microscopes from Leeuwenhoek and a Wilson microscope made by Cuff.36 Thanks to the measurement of the powers of the 26 Leeuwenhoek’s microscopes that were then in possession of the Royal Society, Baker promoted a trend for quantifica-
32 T. FRA¨NGSMYR-J.L. HEILBRON-R.E. RIDER(eds.),The Quantifying Spirit in the 18thCen- tury, Berkeley, University of California Press, 1990.
33 [C.-S. PASSEMANT],Descriptions et usages du microscope, in J.T. NEEDHAM,Nouvelles ob- servations microscopiques, Paris, 1750, pp. 1-28, pp. 22-24.
34 On these scholars, see M.J. RATCLIFF,Europe and the Microscope in the Enlightenment, PhD University College London, 2001, Section 7.3.
35 Archives de l’Acade´mie des Sciences, DB Adanson.
36 H. BAKER,An Account..., cit., pp. 512-513.
tion that would later expand to become a requirement for scientific needs. He computed their magnification, and showed that the best power was 160 diameters (Fig. 4).
In 1723, Martin Folkes had already acknowledged that if Leeuwen- hoek’s microscopes did not magnify as much as other microscopes, their distinctness was nevertheless very good, and indeed Leeuwenhoek pre- ferred «brightness and distinction» to powerful magnification.37Baker’s additional goal was to compare these microscopes to a recent Wilson mi- croscope made by Cuff and belonging to Folkes, now P.R.S, which Cuff also described in a leaflet.38The six powers, from six to one, performed
37 M. FOLKES,Some Account of Mr. Leeuwenhoek’s curious Microscopes, lately presented to the Royal Society, «Philosophical Transactions», 32(380), 1723, pp. 446-453: 451.
38 H. BAKER,An Account..., cit., pp. 512-513; J. CUFF,The Description of a pocket Micro- Fig. 3. Adanson’s test of three microscopes.
the following magnifications: 16-26-44-100-160-400. Baker’s goal was actu- ally to discard both Leeuwenhoek’s microscopes and style of research, and highlight Cuff’s microscopes. Apparently the message was well received, as a 1746 report of Baker’s paper inBibliothe`que raisonne´estated that «the art of using the microscope has much improved since Leeuwenhoek».39
A last test was the selection test developed in the German speaking countries from the 1770s onwards, but not carried out by makers. In 1775, a man named Pelisson, in the Berliner Society of Friends of Nature, published a paper in the journal of the society, in which he compared five microscopes.40The first microscope was a Cuff model made by two Ger-
scope, with the Apparatus thereunto belonging, [London, 1742]. Baker also described it in H. BA- KER,The Microscope Made Easy, London, Dodsley, 1743, pp. 9-13.
39 ANONYMOUS, [Account of Mr. Leeuwenhoek’s Microscopes], «Bibliothe`que raisonne´e», 36, 1746, pp. 324-326: 325.
40 J.P. PELISSON,Vergleichung der bekanntesten und besten Vergro¨ßerungsgla¨ser, nebst kur- Fig. 4. Comparison of 26 of Leeuwenhoek’s microscopes by Baker.
man makers, Ring and Vennebruch in Berlin; there was also a microscope by Adams, another by Hofman with two tubes, and one by Dellebarre, who at this time lived in The Hague. A new device was used in these tests, a copy of Brander’s micrometer, the Augsburg instrument-maker, by Ring from Berlin. Figure 5 shows the results of the comparison.41
Why would one carry out such a test? In fact, the author wanted to reply to a particular question: which was the best microscope to be used
zer Nachricht von einigen im vorigen Jahr angestellten mikroskopischen Versuchen, «Bescha¨ftigung der Berlinischen Gesellschaft Naturforschender Freunden», 1, 1775, pp. 332-350.
41 J.P. PELISSON,Vergleichung..., cit., p. 343.
Fig. 5. Pelisson’s table comparing five microscopes.
by observers, the simple or the double.42Yet, he did not compare simple and double microscopes, but only double microscopes. Other scholars took up that issue. The German scholar and preacher Johann Ephraim Goeze in Quedlinburg had translated two of Charles Bonnet’s works, and was recognised for his naturalistic works on worms. In 1782, he com- pared four German microscopes by Hofman, Ring, Stegmann and Reintha- ler with one by Adams.43 Five years later, another scholar, J.M. Beseke, published a test of five microscopes in a German journal.44 These were two English (Dollond and Cuff) and three German instruments (Hofman, Sturte and Tiedemann). After giving the magnification of each lens for each microscope (Fig. 6), thanks to a Brander micrometer and a device he called a megalometer, he classified all his microscopes.
42 Ivi, p. 333.
43 J.A.E. GOEZE,Versuch einer Naturgeschichte der Eingeweidewu¨rmer thierischer Ko¨rper, Blankenburg, 1782, p. 451.
44 J.M.G. BESEKE,Ueber die Vergleichung einiger zusammengesetzten Mikroskope, «Schrif- ten der Berlinischen Gesellschaft Naturforschender Freunden», 8(2), 1787, pp. 117-124.
Fig. 6. Beseke’s tables comparing the magnification of five microscopes.
The following table 3 shows the optical properties of the five micro- scopes.
TABLE3.Optical properties of the microscopes compared by Beseke
Field Light Colour Outline
Dollond large much bright no distinct
Cuff average much bright no distinct
Hofman A large much bright no much distinct
Hofman B large much bright no poorly dist.
Sturte large much bright no much distinct
Tiedemann very large extr. bright no much distinct
Beseke could thus rank the microscopes according to an average of the various features of each of them, including handling. The Cuff was not so easy to handle, Sturte and Tiedemann both had a good magnification, Tie- demann was less practical than the Hofman, and then came Hofman and Dollond.
What was the common feature of those tests carried out by the Ger- man scholars? They shared technical investigation on several microscopes;
they compared microscopes, used data set on tables, and some of them used these tests to perform microscopical observations. This was quite dif- ferent from an admission test, because they did not discuss functional com- plementarity. They all endeavoured to select the best microscope, taking into account all their features, from optics to mechanics, from handling to prices. And they all compared one or two British microscopes to several German microscopes. Pelisson had compared one Adams to two micro- scopes built by German makers and one by Dellebarre from Holland, Goeze compared one Adams to four German microscopes, and Beseke compared a Dollond and a Cuff to three German microscopes. The issue was not simply to show that German microscopes could stand the compar- ison with the British instruments. In the 1770s-1780s, the German-speak- ing countries strengthened their own advertising policy for instrument making, and indeed, these papers served also for advertising. They all re- called that the price of an Adams or Dollond microscope was much higher than that of an equivalent German device.45
Even if a Dollond microscope could be considered slightly better than a Hofman, its price was three times that of a German microscope, which
45 J.A.E. GOEZE,Versuch einer Naturgeschichte..., cit., p. 451.
was usually more easy to handle.46And an Adams microscope was shown to be no better than many of the instruments made by German makers.
Against the British would-be international advertisement machinery, those selection tests provided a technical answer revealing that British micro- scopes were not optically and practically better than German microscopes at that time; and moreover their prices were much higher. This was cer- tainly a protectionist attitude, linked to economic reasons. The micro- scopes were not advertised by the makers, but by the scholars, and these tests embody the answer to a market competition in reaction to the good reputation of the British devices. Scholars spoke in favour of a market for optical instruments within German-speaking countries, a good ground for an international emerging market with the works by Joseph Fraunhofer.47 Therefore, in addition to the price lists that German makers spread in jour- nals from the 1780s onwards,48users now came to the maker’s rescue, so as to protect an emerging scientific and artisanal community. Such an attempt at democratising the microscope could help to explain the take-off of microscopical studies in the German States at the turn of the nineteenth century.
Nevertheless, to rescue their nationals, scholars had to sign a compro- mise over the lack of standardisation. Indeed, this test took it for granted that all microscopes were standardised and aimed at selectingthebest mi- croscope, almost without taking into account the realm of functional com- plementarity. Highlighting one microscope against others in the absence of standardisation means to ignore or neglect this issue, to embrace a rheto- rical strategy, or to select very good devices. When these scholars rescued their national makers, they adopted a more technical and abstract style of advertising than the previous one, illustrated by leaflets and catalogues of instruments from the seventeenth century makers. As scholars used strate-
46 Ivi, p. 451; J.M.G. BESEKE,Ueber die Vergleichung..., cit., p. 122.
47 On Fraunhofer, see M.W. JACKSON,Spectrum of Belief. Joseph von Fraunhofer and the Craft of Precision Optics, Cambridge MA, London, the MIT Press, 2000.
48 S.G. HOFMAN,Verzeichniß der neuesten optischen Instrumente, «Litteratur und Vo¨lker- kunde», 7, 1785, pp. 374-380; J.-H. TIEDEMANN,Beschreibung der von ihm verfertigten Zusam- mengesetzten Vergro¨ßerungsgla¨ser; Stuttgart, 1785; J.G. STEGMANN,Preis-Verzeichniß der physika- lischen und mathematischen Instrumente, «Journal von und fu¨r Deutschland», 3(1), 1786, pp. 72- 75; F.A. JUNKER,Nachricht von einem brauchbaren und wohlfeilen Sonnen-Mikroskop, «Magazin fu¨r das Neueste aus der Physik und Naturgeschichte», 7(3), 1791, pp. 84-87; W. BURUCKER,Prei- se der Instrumente des Hrn. Burucker, «Technologisches Magazin», 2, 1792, pp. 263-265. On Brander, see I. KEIL,Microscopes made in Augsburg(this volume).
gies taken from the market, the alliance between users and makers took on a new shape.
CONCLUSION
In this paper I examined various sorts of tests of microscopes that have revealed several kinds of interaction linking makers and users. Between re- search of prestige and scholarly quest, between the needs for measure- ments and marketing strategies, it appears that during the Enlightenment scholars as well as makers already used procedures for comparing and test- ing microscopes. There was a clear difference in testing microscopes for scientific reasons and for advertising purposes, within economical contexts variously sensitive to the pressure of the British marketing culture on the Continent. Certainly not all-embracing, this paper has pointed out several kinds of relations between makers and scholars that differ according to both cultural variety – French scholars seldom cited makers – and the ten- sion between market pressure, scientific requests and needs for instrumen- tal standardisation.
