LEEUWENHOEK’S MICROSCOPES ol’ 
view'd unless spread upon Glass, he first fitted them on a 
little Plate of Talk, or excessively thin-blown Glass, 
which he afterwards glewed to the Needle, in the same 
Manner as his other Objects. 
The Glasses are all exceedingly clear, and shew the 
Object very bright and distinct, which must be owing to 
the great Care this Gentleman took, in the Choice of his 
Glass,’ his Exactness in giving it the true Figure; and 
afterwards, amongst many, reserving such only for his 
Use, as he, upon Tryal, found to be most excellent. 
Their Powers of magnifying are different, as different Sorts 
of Objects may require; and, as on the one Hand, being 
all ground Glasses, none of them are so small, and conse- 
quently magnify to so great a Degree, as some of those 
Drops, frequently us’d in other Microscopes; yet, on the 
other, the Distinctness of these very much exceeds what 
I have met with in the Glasses of that Sort. 
Folkes gives no figures and no further information of 
material importance, though he makes the interesting state- 
ment that Leeuwenhoek had previously presented to Queen 
Mary, when she visited him at Delft, ““A Couple of his 
Microscopes, which, as I have been inform’d by one who 
had them a considerable Time in his Hands, were of the 
same Sort as these, and did not any ways differ from one of 
the 13 Cases contain’d in the Drawers of this Cabinet.” ® 
ss —  —  —— — —  — — —— 
‘This is a very shrewd remark. Undoubtedly L. knew a great deal 
about glass, and he was an expert glass-blower—as his recorded experiments 
prove. He learnt the art by watching a professional at the fair in Delft, 
and then practising by himself at home. 
* Mary II of England, wife of William III of Orange. She died in 
1694. Folkes calls her “the late Queen Mary,” and clearly did not mean 
her sister and successor, Queen Anne (died 1714). Halbertsma (1843, p.14) 
appears to have confused these two Queens when he says that L. was 
visited by “ Anna Maria.” 
* Folkes (1724), pp.450-1. Nothing else is now known about these 
instruments, which have long since vanished—like those presented to the 
Royal Society. 
