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The production of the m icroscope was also determ ined by its practice and by the p articu lar needs expressed by scholars for features, m orphology and im provem ents. N otably, the shape o f m icroscopes influenced the kind o f p osition taken for observation, the style o f science practiced, and, indirectly, the dem and of

scholars for m icroscopes. It is indeed d ifficult to draw

m orphological and even m ore, p h y sio lo g ical co n clu sio n s about

5 5 See D aum as 1953, 187. M usschenbroek 1739, 18, 42, 585-595; N ollet 1753 I, 50-56; B risson 1781 II, 135-145 included the term “m icroscope” in his D ictio n a ry o f P hysics.

anim alcules from the flickering im ages observed through a hand m icroscope. In this respect, the death o f L eeuw enhoek m arked the end of an era and helped to determ ine the fate of the practices of the m icroscope up to the 1740s. In his w ill L eeuw enhoek had bequeathed 26 o f his m icroscopes to the R oyal Society w hich arrived in E ngland in 1723. As a kind of eulogy read before the Society, M artin Folkes introduced the m icroscopes, each o f w hich had a particular object fixed w ith glue, though several objects had broken off, during the travel. R egisters from the hand o f

L eeuw enhoek were added to the gift that enabled the fellow s “to exam ine m any of those objects, on w hich he had m ade the m ost c o n sid e ra b le d i s c o v e r i e s ” . 5 7 Am ong the objects were blood

globules and desiccated animalcula in semine masculino. The rest was com posed of tiny parts of insects, anim als or plants: eyes of gnats and flies, fibres o f fish and tongues, hairs o f various origins, parts of bones, organs o f spiders, vessels o f plants, and so on. Folkes balanced the qualities o f the m icroscopes w ith the skill of the observer: “H ow ever excellent these glasses m ay be ju d g ’d, Mr. L eeu w en h o ek ’s discoveries are not entirely to be im puted to their go odness” . The judgm ent, experience and assiduity o f the man each played a role, creating a sort of m ythical standard for

m icroscopical investigation: “it can be im agined any other person can do, that neither has the experience, nor has taken the pains this curious author had so long done” . Folkes particularly

rem inded his audience that the m icroscopes sent to the Society were proofs of L eeuw enhoek’s skills in preparing objects. B ut the results of this analysis turned out to be rath er deceptive. Folkes recom m ended his listen ers not to

rashly condem n any o f this g e n tle m a n ’s o b se rv a tio n s, th o ’ even w ith his own glasses, we should not im m ediately be able to verify them ourselves.^ ^

This passage is highly significant and indicates the status the Royal Society granted to L eeuw enhoek’s observations. They h a d to be accepted regardless o f the fact that other scholars w ere unable to rep eat them , even if they had L eeuw enhoek’s m icroscopes in hand. T here could hardly be a better description o f the elitist

m i c r o s c o p e .

As a result it sounded more im pressive that the m an was

reliab le, rath er than that his observations w ere rep ro d u cib le, and thus assim ilable to the general netw ork of scientific data. This is another sign of the absence of integration o f L eeu w en h o ek ’s works w ith the scientific netw ork, resulting in the heroisation o f the man h im self as a kind of reliable curiosity: “There can be no reason to d istru st his accuracy in those others [discoveries] w hich have not yet been so frequently or carefully e x a m i n ’ d ” . ^ 9 i f m any scholars

before and after L eeuw enhoek acknow ledged that his m ethod for m aking and using m icroscopes were unknow n, the solution that Folkes proposed —to accept, despite any rep etitio n , his

o bservations because the m an was reliab le— only served to shelve the problem . It is certain that L eeuw enhoek co ntributed to the form ulation o f im portant skills. Still his attitude im peded these skills to be turned into standards, both for m aking m icroscopes and for its use. W itnesses for this fact are not lacking: “I had not” , rep o rted A rchibald A dam s in 1710,

an o p p o rtu n ity o f ex am in in g M r L e e u w e n h o e k ’s g lasse s p a rtic u la rly , w hich is a favour he allow s to none.^®

^ ^ T hese quotations, Folkes 1723, 452. 5 9 Folkes 1723, 453.

L eibniz equally begged Leeuw enhoek to divulge the secret o f his m icroscopes, as w ell as his m ethod o f observation to scholars. No trad itio n o f these skills could thus be transm itted, conserved and im proved up by the contem porary and subsequent generations of s c h o l a r s . I n a sense, this was a waste of time: “W e are under very g reat disadvantages for w ant of the experience he had” ,62 said F olkes before the Society. The decrease in m icroscopical

publications in B ritain in the period 1700 to 1730, as well as the low num ber o f quotations o f Leeuw enhoek in the first p art o f the century should probably be linked to his resistan ce to publicising his know -how and know ledge o f the m icroscope. C ontrasting w ith the pathetic appeal from Folkes to “pursue those en q u iries” ,63 the studies on m icroscopical topics like blood, anim alcula or the anatom y o f tissues, ceased in B ritain betw een 1723 and 1740. E x cep t for rath er episodic rem em brances as opposed to references given by Sloane or others,64 the L eeuw enhoek “legacy” in E ngland was buried by the tim e of, and probably long before, the scien tist’s death. In B ritain the years 1723-1725 saw the last breath of

s e v e n te e n th -c e n tu ry m ic ro sc o p ic a l resea rch . L e e u w e n h o e k ’s

posthum ous papers w ere published in 1723, and F o lk e s’ paper was actually closer to a funerary address or an apology than an eulogy. O ther scholars who used the m icroscope had sim ilarly th eir works p u b lish ed before 1725. Jam es Jurin (1684-1750), one o f the rare people who had im proved the techniques o f w eighting and

m easuring blood corpuscles in the late 1710s, did not reply to the

61 In this m eaning, w hich I believe to be the historical one, there is n o e x istin g L eeuw enhoek legacy, unless we w ant to co n sider a w ill to be w ritten fo r p eople not yet born...

6 2 Folkes 1723, 452. 6 3 Folkes 1723, 453. 6 4 Sloane 1733, 100.

criticism s raised in 1722 by the Italian scholar Pietro A ntonio M ichelotti on the separation of bodily f l u i d s . T h e works by Patrick B lair on vegetable physiology and the com pilation of

n a t u r a l i a that included m icroscopical works by R ichard B radley (1688-1732) had also been published in 1720 and 1721,

resp ec tiv e ly . M oreover, the m icroscope by C u lp ep er (1660-1738), said to have been prom oted in 1725,^6 did not actually produce p articu larly obvious echoes, and no one ventured to speak of anim alcules any more. Even with Stephen H ales w hose 1727

Vegetable Staticks was also very quiet on the subject of

m icroscopes, it is not before the m id-1730s that new perspectives on using the m icroscope appeared.

B oth sim ple and com pound m icroscopes p resen ted certain problem s related to the vibration, venue o f light, fine adjustm ent screw , and to fitting the objects. At high m agnifications, the very sm all distance betw een the specim ens to be observed and the objective or lens caused problem s in lighting the object, and both W ilson and C ulpeper’s m icroscopes did not allow the alive setting o f parts o f taller creatures. For instance still in D ecem ber 1761 A lbrecht von H aller, who could not observe parts o f a full egg being disturbed w ith the tripod o f his C ulpeper m icroscope, asked C harles B onnet for other s o l u t i o n s . N e w m icroscopes invented since the m iddle of the thirties, and by C uff later, solved these two p roblem s. B ut here astronom ical research in flu en ced the 1740s developm ent o f m icroscopy. A telescope using m irrors had been invented in the 1610s by Father Zucchi, a Jesuit from Parm a, and

^ ^ M ichelotti 1721. For a biography o f Jurin, see R usnock 1996, 8-22. C ulpeper’s leaflet does not give a date. See C&C 1932, 108-115. 67 Sonntag 1983, 250-251.

later, in 1672, N ew ton designed his catoptric m icroscope, believing th at the optical lim itations o f the lenses could not been overcom e. In 1728 the F rench instrum ent m aker, Jacques L em aire, presented a new catoptric telescope to the A ca d ém ie des sciences. This kind o f project was taken up and applied to the m icroscope, because R obert B arker, in 1736, and Robert Sm ith in 1738, claim ed to have im proved the catoptric m icroscope, u sing tw o m irrors. N ew to n ’s reflectiv e m icroscope needed only one m etal m irror, w hile those o f B arker and Sm ith had two.^^ Both fitted a large concave m irror in which an ocular with two lenses had been set in the m iddle, the light, therefore, being reflected in a second sm aller m irror {Fig.

L ).^9 In B ark er’s, the distance betw een the object and the m irror was betw een nine and 24 inches, leaving enough space for m anipulation, changes in light and larger objects. B arker first subm itted the principles o f the catoptric m icroscope to the R oyal Society in 1736, but the instrum ent was ju d g ed to be not very e f f i c i e n t . A second m odel released in 1740 was m uch better, and this m icroscope continued to be sold for som e y e a r s . 7 1 It had three advantages over the com m on m icroscope: first, the object could be exposed to any degree of light and not be perturbed by the sm all distance of the objective to the object as was the case for the refractin g m icroscope. Second, the object did not need to be

transparent. Even opaque objects could be highly m agnified. T hird, this technique allow ed the m agnification o f sm all details o f whole creatures, and allow ed one to observe the circu latio n o f the blood.

^ ^ B arker 1736a, pl.; B arker 1736b, 432; An. 1740, 165. 6 9 B arker 1736b, 433-434; Sm ith 1767, 124.

7 0 In 1736, the m icroscope was but “an essay of a construction, to w hich one should com e back to im prove it” (An. 1740, 166). L ater, an im proved m icroscope was presented (An. 1740, 168).

7 i It was used at least until 1745 (Parsons 1745, 260-261) and probably by N eedham in 1750.

en

y.My^Ji

F ig, L B arker's 1736 catoptric m icroscope or double reflecting m icroscope (left), and (right) B arker’s 1740 im proved catoptric m icroscope (B arker 1736a; B arker 1740, 170).

and any kind o f m otion in a live anim al 7^ A m ong the different steps in the history o f increasing freedom o f form and function of the m icroscope, the catoptric m icroscope gave way to the

possibility o f experim enting on live beings and im proved the flexibility in light use.

Two new m icroscopes were also invented in the late 1730s. In 1738, during the E nglish leg of his grand tour o f Europe, the G erm an MD Johann N athaniel L ieberkhun (1711-1756)

dem onstrated the concave m irror w hich carries his nam e, and two new m icroscopes, the solar m icroscope and the sim ple m icroscope for opaque objects before certain craftsm en and o th er m em bers of the R oyal S o c i e t y . A few years later im proved versions of these m icroscopes w ere being sold by C uff and by other B ritish

m anufacturers. A long w ith the cato p tric m icroscope w hich signaled the revival o f the m arket for m icroscopes, the two new m odels brought to E ngland by L ieberkhun allow ed the instrum ent m aker to sell a m inim um o f five different types o f m icroscopes in the early 1740s. As a consequence the m icroscope acquired better visibility in the titles o f leaflets and in certain m icroscopical

research. A period of fifteen to tw enty years had therefore been necessary to clear away the outdated context of dealing w ith and p ro d u cin g the m icro sco p e.

7 2 B arker 1736b, 434-435; An. 1740, 165. 7 3 C&C 1932, 189.

3.4 Henry Baker and new strategies for an emerging