234 Fulminating Gqld. [Book VI* 



variety of Jubilances, but its appearances are very va- 

 rious, according to the nature of the matter employed. 

 Lime and magnefia precipitate gold in the form of a 

 yellowiih powder, and the fixed alkalies have the fame 

 effect. Volatile alkali produces a more quick and 

 copious precipitation, and forms the remarkable com- 

 pound, known by the name of aurum fulminans, the 

 nature of which has been already intimated in a note 

 under the head of ignition. I mall in this place, how- 

 ever, add a few obfervations, which may tend ftill fur- 

 ther to illuftrate its nature. In the firft place, it ap- 

 pears that the fulminating gold is a compound of 

 about three parts of that metal with one of volatile 

 alkali. Secondly, Fulminating gold, expofed to fuch 

 a heat as is fumcient to feparate the volatile alkali^ 

 without letting fire to the compound, lofes its fulmi- 

 nating property. The fame effect is produced by fub- 

 mitung it to the action of concentrated vitriolic acid, 

 melted lulphnr, asther, or any fubftance capable of 

 abftracting the Volatile alkali by fuperior affinity. 

 Thirdly, When a few grains of fulminating gold arc 

 detonated in copper tubes, the extremity of which is 

 plunged beneath the mercury of the pneumato- chemi- 

 cal apparatus, azote is diiengaged, a few drops of water 

 are produced, and the gold is reftored to its metallic 

 appearance. M. Berthollet, the inventor of this ex- 

 periment, concludes, that the volatile alkali is decom- 

 pofed, and that while one of its component parts, hy- 

 drogen, unites with the oxygen of the calx of goldj 

 and forms water, its other component part, azote, eP 

 capes in the form of gas. The readinefs with which 

 fulminating gold explodes feems to depend on the 

 tendency which the hydrogen of the alkali has to unite 

 with the oxygen of the metallic calx, which tendency 

 the wsak attraction of the gold for the oxygen on the 



one 



