( 153 ) 



a bundle (3f arrows tied together, with their ends pointing dif- 

 terent ways. 



Belides the foregoing obfervations, I faw, at the firll firing or 

 explofion of the Gunpowder, a very thin moillure in the upper 

 part of the glafs, which feemed to confill of globules of different 

 fizes ; which moill fubftance, I was well perfuaded, did for the 

 moft part proceed from the faltpetre, and which I fliall therefore 

 call oil of faltpetre, though it might perhaps be mixed with fome 

 of the oil of fulphur. In order more fully to fatisfy myfelf in this 

 refped, I put into one of the glafles fome refined faltpetre, leaving 

 a fmall opening at the top of the glafs, that it might not burft in 

 the experiment, and then applied fo ftrong a heat to it that the 

 faltpetre boiled very much ; my only view in this was, to examine 

 the vapour or moifture which arofe from the faltpetre, and to 

 which I have given the name of oil ; and I perceived, in the upper 

 part of the glafs, a large quantity of tranfparent and very fluid 

 matter, which, upon infpeftion, could be denominated no other 

 than oil. At another time, I faw this fubftance or oil fo colleAed 

 or run together, that it appeared like drops of water fpread irregu^ 

 larly upon the glafs. 



Not content with the preceding obfervations, I provided fome 

 other veflels of very thin glafs, in order to purfue my obfervations 

 with more dillinftnefs, and to fee if I could not get a view of the 

 changing of the faltpetre particles from globular to hexagonal 

 figures, to which intent, immediately as the Gunpowder in the 

 gtafs was fired, I brought the glafs before the view of the microl- 

 cope, and then I faw; the globular particles of faltpetre chtinge 

 their figure to hexagonal, and this was performed infiantaneously, 

 or as quick as a flafli of lightning to the eye, not in one or a few 

 of the particles, but all of them, as I may fay, in a moment ; and 

 though at the bottom of the glafs, where the greatell number of 

 particles fubfided after their firll motion ceafed, I faw an immenfe 

 number of fmall pai'ticles lying to which 1 could not afiign any 



Vol. II. U 



