EfftBs of ikt ntw fulminating Mat cwy on ArlilUry-^ (3c. 253 



Experiment 6. A fea grenade, 3.5 inches diameter, charged like the fliell intthe laft ex- 

 periment, was burft into numerous fragments, by 5 of an ounce avoirdupois of the mercu- 

 rial powder. The fragments were projefled with but little force, and only to the diftance 

 of eight or ten yards. The charge of gunpowder required for grenades of this fize, is 3 

 ounces. 



Experiment 7. A fea grenade, of the fame diameter as the laft mentioned, and charged 

 in the like manner, with § of an ounce avoirdupois, or 57^ grains, of the mercurial pow- 

 der, was fpjit into two equal pieces, which were not thrown ten inches afunder. 



The report in the four laft experiments was very (liarp, but not loud in proportion.^ 



It feems, from the manner in which the fwivel was burft, in the fourth experiment, tftat' 

 a fmallet charge would have been fufficient for the purpofe. We may therefore infer, both . 

 from this inftance and from the fecond experiment made with the gun, in Seftion v, that 

 any piece of ordnance might be deftroyed, by employing a quantity of the mercurial pow- 

 der equal in weight to one half of the fervice charge of gunpowder; and,, from the feventh 

 and laft experiment, we may alfo conclude, that it would be poflible fo to proportion the 

 charge of mercurial powder to the fize of difF^rent cannons, as to burft them without dif- 

 perfmg any fplinters. But the great danger attending the ufe of fulminating mercury, on 

 account of the facility with which it explodes, will probably prevent its being employed 

 for that purpofe. 



In addition to the other Angular properties of the fulminating mercury, it may be ob- 

 ferved, 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 rcfifting itsaflion. Mr. 

 Cruickftiank, who made fome of the p'owder, 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 collefted moft, if not all, of the grains of gunpowder.. Can this extraor- 

 dinary fafl be explained by the rapidity of the combuftion of fulminating mercury .' or is- it 

 to be fuppofed, (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. Cruickftiank, I find that he 

 has made many accurate experiments on gunpowder ;, and he has permitted me to ftate,. 

 " that the matter which remains after the explofion of gunpowder, confifts of pot-afh 

 " united with a fmall proportion of carbonic acid, fulphate of potafti, a very fmall quan- 

 " tity of fulphuret of pot-afli, and unconfumed charcoal. That 100 grains of good gun- 

 " powder yield about 53 grains of this refiduum, of which three are charcoal. Thatit is 

 " extremely deliquefcent, and, when expofed to the air, foon abforbs moifture fufficient 

 '♦ to diflblve a part of the alkali; in cohfequence of which, the charcoal becomes expofed, 

 •' and the whole aflumes a black or very dark colour." Mr. Cruickftiank likewife informs 

 me, that after the combuftion of good gunpowder wnder mercury, no water is ever 

 perceptible. 



3. Referettcti, 



