(’ 479 ) - 
li Mkrofcofkd OhferVations upon the Configuration 
of Diamonds : In a Letter from Mr. Antony 
Van Leeuwenhoek, F. % S. 
Honourable Gentlemen, 
I Take the Liberty of troubling you again with thefc 
my following Obfervations, which I have had Iain by - 
me thefe three YeSrs, within which time I caufed them to 
be delineated'by my Painter, and engraven upon a Cop- 
per-Plate^ the Draught ot which I here fend You. 
I have been often ask’d, whether I could difcover any 
thing particular^ the Configuration of Diamonds^ where- 
upon fbme Years ago, Itookafraall polifh’d Diamond^ 
and broke it to Pieces with a Pair of Pincers^ but having, 
obferved nothing mote in the broken Particles thereof, 
than in thofe of Common GJafs, I laid afide all Thoughts 
of it for that time; , t r 
■ Some Months ago it came into my Head, that I ihoud 
have . made my Remarks not upon polilh d, but ruff Dia- 
Whereupon I procur'd a few fmall ruff Diamonds from 
a Jeweller, fome of which I placed'before a Microfcope,. 
and obferved one of them more particularly 5 concerning 
which I concluded, that all thofe Streaks or Fibres which 
I faw in it, were nothing more than the feveral Coagula, 
tions or Augmentations it had receiv’d from time to time, 
and that in a very (hort fpace, . 
