DE GRAAF AND THE ROYAL SOCIETY 41 
certain most ingenious person here, named Leewenhoeck,' 
has devised microscopes which far surpass those which 
we have hitherto seen, manufactured by Eustachio Divini 
and others. The enclosed letter from him, wherein he 
describes certain things which he has observed more 
accurately than previous authors, will afford you a sample 
of his work: and if it please you, and you would test the 
skill of this most diligent man and give him encourage- 
ment, then pray send him a letter containing your 
suggestions, and proposing to him more difficult problems 
of the same kind. 
The enclosed specimen of Leeuwenhoek’s work consisted 
of various rather crude observations on Mould; on the sting 
and mouth-parts and eye of the Bee; and on the Louse. It 
was published in English in the Philosophical Transactions * 
with some comments by Oldenburg, who wound up by 
remarking (somewhat sardonically, I fear) “So far this 
observer: who doubtless will proceed in making and imparting 
more Observations, the better to evince the goodness of these 
his Glasses’”—a prophecy which was actually fulfilled more 
amply during the next fifty years than anybody could then 
have thought possible. Yet the Fellows evidently liked the 
observations, and Oldenburg was instructed to communicate 
with their author. To his letter Leeuwenhoek sent the 
following characteristic answer from “‘ Delff in Hollant”:* 
(1671, p. 97) remarks “We have now finisht a sharp and bloody War, which 
nevertheless leaves not the least rancor (that I know) in the heart of any 
English man; and the reason of it is, because we have generally an affection 
for these our neighbors [the Dutch], esteeming them an industrious and 
sober people’’. 
* So spelled in original. 
2 Letter 1. See Phil. Trans. (1673), Vol. VIII, No. 94, p. 6037. The 
original MS. has not been preserved by the Society, and is presumably no 
longer extant. 
® Translated from Letter 2 (15 August 1673). MS.Roy.Soc. The original 
is in Dutch. Cf. Plate X. The drawings were engraved and published in 
Phil. Trans. (1673), Vol. VIII, No. 97, but their originals are lost. The 
part of this letter here translated has not been published previously, but 
some extracts from the remainder were printed—in English, in two parts— 
in Phil. Trans. (1674), Vol. IX, No. 102, pp. 21-25. 
