C 3 
yi. An Experiment concerning the nitrous Par- 
ticles in the Air 5 ly the fame Hand, 
I Took a fmall Gally-pot, fuch as the Apothe- 
caries in the North of England make ufe of, 
where I was when I made this Experiment, and 
ground the Top of it very fmooth and true, and 
adapted thereto a Cover of blue Slate, which 1 had 
likewife ground with much Care. Into this Gally- 
pot I put equal Quantities of Nitre and Flour of 
Sulphur, about a Drachm of each. I then fixed on the 
Cover, putting it into a new Digefter 5 but the Height 
which I raifed the Heat to, and how long I continued 
it, I do not exadlly remember, but believe it was 
three or four Seconds. When I opened it the Day 
following, I perceived fomething had tranfpired be- 
twixt the Top of the Gally-pot and the Cover j the 
top Edges of the Gally-pot, where the Glazing was 
ground off, being difcolour'd, though the Nitre and 
Sulphur were very little diminifhed as to their Weight ; 
only they were melted into one Lump, which I took 
out of the Gally-pot. 
And having fet the empty Gally-pot upon a Shelf, 
upon looking at it the next Day, I found long hoary 
Hairs, very bright and brittle, all around the ground 
Edges of the Pot, very fpecious to behold. After I 
had admired them a while, I gathered them, and, 
rafting them, found them to be pure Nitre. I 
then fet the Pot upon the Shelf again, and in three 
or four Days, ftill finding there were frefh Shoots 
made, as large and fpecious as at the firft, I gathered 
them a fecond and third time j fo that I fuppofe the 
Pot 
