1^0 On a iiezv fulminating Mercury. 



both from this initance and from the fecond experiment made 

 with the gun, in Seftion V, that any piece of ordnance might 

 bedeftroyed by employing a quantity of the mercurial powder 

 equal in weight to one-half of the fervice charge of gunpow- 

 der ; and, from the feventh and lad experiment, we may alfo 

 conclude that it would be poflibie fy to proportion the charge 

 of mercurial powder to the fize of different cannons, as to 

 burft them without difperling any fplinters. But the great 

 danger attending the ufe of fulminating mercury, on account 

 of the facility with which it explodes, will ptobably prevent 

 its beuiff employed for that purpofe. 



In addition to the other Angular properties of the fulmi- 

 nating mercury, it may be obferved, that two ounces inflamed 

 in the open air, feem to produce a report much louder than 

 when the fame quantity is exploded in a gun capable of re- 

 lifting its aftion, Mr. Cruickfliank, who made fome of the 

 powder by my procefs, remarked that it would not inflame 

 gunpowder. In confequence of which, we fpread a mixture 

 of coarfe and fine grained gunpowder upon a parcel of the 

 mercurial powder ; and, after the inflammation of the latter, 

 we colleAed moft, if not all, of the grains of gunpowder. 

 Can this extraordinary fact be explained by the rapidity of 

 the combuftion of fulminating mercury? or is it to be fup- 

 pofed, (as gunpowder will not explode at the temperature at 

 which mercury is thrown into vapour,) that fufficient caloric 

 is not extricated during this combuftion ? 



From the late opportunity I have had of converfing with 

 Mr. Crujckfhank, I find that he has made many accurate 

 experiments on gunpowder; and he has permitted me to 

 flate, " that the matter which remains after the explofion of 

 guripowder, confifts of potafh united with a fmall proportion 

 of carbonic acid, fulphat of potafli, a very fmall quantity of 

 fnlphuret of potafh, and unqonfumed charcoal. That lOO 

 «.-rains of good gunpowder yield about ^^ grains of this refi- 

 4uum, of which three are charcoal. That it is extremely 

 deliquefcent, and when expofed to the air, foon abforbs 

 moifture fufficient to difTolve a part of the alkali ; in confe- 

 quence of which, the charcoal becomes expofed, and the 

 whole affumcs a bl^ck, or very dark colour." Mr. Cruick- 



fhanl; 



