On a new fulminating Mercury. i2'/ 



nt mercury, yielded, at the end of the operation, about three 

 grains of a gray precipitate, which fuhninated with extreme 

 violence. Mr. Cruickfliank had the goodnefs to repeat the 

 experiment : he dilTolved 40 grains of iilver in two ounces of 

 the ftrongeft nitrous acid diluted with an fequal quantity of 

 water, and obtained (by means of two ounces of alcohol) 

 60 grains of a very white powder, which fulminated like the 

 gray precipitate above defcribed. It probably combines with 

 the fame principles as the merciirv, and of courfe differs from 

 Mr. Berthollet's fulminating filver, alluded to in page 230. 

 I obferve that a white precipitate is always produced in the 

 firft inftance, and that it may be preferved, by adding water, 

 as foon as it is formed ; oiherwife, when the mother liquor 

 is abundant, it often becomes gray, and is re-diliolved. 



P. S. Since the preceding pages were written, 1 have been 

 permitted, by the Right Honourable Lofd Howe, Lieutenant 

 General of the Ordnance, to make the following trials of the 

 mercurial powder, at Woolwich, in conjunftion with Colonel 

 Blomefield and Mr. Cruickfhank*. 



Experiment I. From the manner in which the fcrew of 

 the gun-breech, mentioned in Se6lion V. had afted on the 

 barrel, it was imagined, that by burfting an iron cafe, exaftly' 

 fitted to the bore of a cannon, its fudden enlargement might 

 make many flaws, and fplit the piece, without difperfing any 

 fplinters. In conformity to this opinion, a cafh iron cafe was 

 conftru6led, with a cylindrical chamber, of equal length and 

 diameter, calculated to hold 3^th ounces troy of the mercu- 

 rial powder. The cafe, being firmly fcrewed together, was 

 charged through its vent-hole, and introduced into a twelve- 

 pounder carronade, the bore of which it exaftly fitted. The 

 pow^der was then inflamed, with proper precautions. The 

 gun remained entire, but the cafe divided : the portion form- 

 ing the upper furface of the chamber was expelled in outj 

 mafs; that adjoining the breech, which confiituted the reft 

 of the chamber, was cracked in every direction, and in part 

 crumbled j yet it was fo wedged into fome indentations 



* It is with pleafure I take this opportunity of acknowledging the civil 

 attention I received from the different officers. 



which 



