( IJi ) 
eluded that they were of an - Hexangniaf Figure, and 
conlequently that they were Salt-peter Particles. 
From thefe Obiervations, T confidoi'M with tiry felf, 
whether all thofe Salt Particles, in which, I fa id before, 
I had difeover’d fo many diflerent Figures, , were not 
Originally of the fame Shape with thofe very flender 
Salt Particles that I difeover’d vvhen I dillolved the Cor- 
ral in the Aquafortis^ notwithflanding they were a thou- 
fond times fmaller than they appeared thro’ theJVIicro*- 
fcope ; and the difference of their Figures may perhaps 
be only occafion’d by the Acceflion or Coagulation of 
other Particles, wliich in one place may be greater or 
lefs than in another; and accordingly the Figure and 
Size of them are determined by their nearnefs or diftance 
from one another. 
Afrer this I broke off twb little Pieces of Red Corral 
from a fmall Shell 1 had lying by me, and which is de^ 
feribed in a preceding Letter, by Fig. 4. Letter A ; and 
placed that likewife upon a piece of Wood-coal, which 
I made red' hot by blowing on it the Flame of a Wax^ 
Candle ; and in that condition threw it into a little clean 
Rain-water, and prcfently obferved the Corral to be 
diffolvcd into a fine White Matter, and foon after the 
Matter overfpread with a Scum; which from time to 
time encreafe'd in thicknefs ; and about two hours after, 
amongfl the infinite Number of exceeding fmall Salt 
Particles, I fa w feme of a larger fize coagulated, agree- 
ing with the aforementioned Salt Particles ; in fhort, one 
wou’d imagine, that the Salt Particles that were fepa-- 
rated from that little piece of Corral,- and which were 
coagulated in and upon the Water, did aitogether make 
a greater Body than even all the Parts of the Corral it 
felf would amount to. 
Now having been informed, that a certain Phyfician 
or Surgeon feffeemed by fome Perfons, but of fmall Re- . 
• with others who have Skill in Phyfick; did make 
ufe, 
