Chap. 34.] Fulminating Silver. 221 



the action of nitrous acid, which diflblves the fiiver 

 and leaves the gold, and the above method is ufcd ro 

 obtain the filver from the acid. 



To make the famous fulminating filver, which is fo 

 truly formidable in its effects, a fmall quantity of filver 

 is difiblved in pale nitrous acid (or aqua fortis) from 

 which it is precipitated by lime water. The calx or 

 precipitate is to be dried by expofure to the air for 

 three days. Tiie inventor, M. Bertholet, fyppofes 

 the action of light to have alfo fome influence in the 

 fuccefs of the experiment*. The dried calx is then 

 agitated in a folution of the cauitic volatile alkali, 

 when it arTumes the form of a black powder, which is 

 Jeft to dry in the open air. The fulminating filver 

 then confifts of an union of the calx of filver with vo- 

 latile alkalj. 



The effects of this preparation are tremendous, and 

 infinitely exceed thofe of gunpowder, fulminating pow- 

 der } or fulminating gold. It explodes with the flighteft 

 agitation or friction. The falling of a few atoms of 

 it from a moderate height produces a violent detona- 

 tion, and a drop of water falling upon it has the fame 

 effect. When it is once fully prepared, it muft not 

 be touched or moved into any other vefiel, but mull 

 remain in that in which it was dried j and to make the 

 experiment with tolerable fafety, not more than a grain 

 of filver mould be employed in the procefs. The 

 caufe of thefe explofions has been already intimated in 

 the chapter on ignition, and will be further illuftrated 

 in treating of fulminating gold. 



Though the nitrous acid difiblves filver with greater 

 eafe, it has not fo ftrong an attraction for it as the mu- 

 riatjc or vitriolic acids. Either of thefe, dropped 



* Journal de Phyfique for June 1788, p. 474. 



