C *4*5 ) 
VI. Tart of a Letter written to Signior Antonio 
Magliabechi, by Mr Anthony Van Leeuwen- 
hoek, F. R. S. concerning the Tarticles of Silver 
diffolVed in Aqua Fortis, Zsrc. 
Delft, March 12. 1705. 
I Take the liberty to acquaint you, Honoured Sir, that 
I communicated to you fome Months ago my Opi- 
nion concerning Diamonds ; the fum of which was, 
that they do not grow bigger by lying in the Earth, but 
that their magnitude and figure is affumed at once, and 
at the very time of the coagulation or coalefcence of the 
Particles which compofe them. 
I was the more confirmed in this my foregoing Opi- 
nion, by putting Silver (which I have done feveral times) 
into a Glafs Tube, that was about the thicknefs of my 
Finger, and length of my Hand $ upon which Silver 1 
poured as much Aqua Fortir,os was fufficient to diffolve it. 
I put this Glafs Tube, which was a third part filled 
with Aqua Fortis impregnated with Silver, into a Pot 
filled with Sand, and placed it aimoft Horizontally, and 
fo as that it might not ftir any way, in hopes that [ 
might the better obferve, (after a few Days,) the coagu- 
lating Particles, fubfiding to the bottom, all along the 
length of the Tube. 
Having view'd this Glafs Tube with a Microfcope, I 
obferved divers fmall long Particles coagulated, which I 
judged to be Particles of Salt Petre $ for as I turn’d the 
Tube a little before my Eyes, and as gently as I could, i 
put thofe Particles into a little Motion, and thereby at 
once difcover’d three (idee of them, which I imagined to 
14 Z be 
