^4*^ Experiments in Galvanic EleiJricify. 



" 6. That when the gafes, obtained by gold or platinu 

 wires, are colle6led together and exploded over mercury, 

 the whole nearly difappears and forms water, with pro- 

 bably a little nitrous acid, for there was always a thick 

 white vapour perceived for fome time after the explofion. 

 The refiduarygas in this cafe appeared to be azot." 



Acid folutions of metals having been decompofed, Mr. 

 Cruickfhank tried their fclution in alkalies. Pure ammonia 

 ^vasadded to a dilute folution of nitrat of filver, till the mixture 

 ifmelled ftrongly of the former. Being put into a tube in the 

 ufual way, with filver wires, and the communication made, a 

 'rapid produftion of gas took place from the filver end, but 

 hardly any from the zinc. Grayifh fiafhes of metallic filver 

 w6re feparated from the filver wire, and on the zinc wire a 

 dark gray fubftance was depofited, which, on afterwards 

 ■endeavouring to fcrape it oif with the finger, exploded, 

 though fiiill moift. The wire was corroded and full of holes. 

 The fulminating filver of BerthoUet had in faft been pro- 

 duced in this experiment. 



When pure ammonia was introduced into the tube 

 in place of the folution of the nitrat of filver, the re- 

 fult was the fame — the filver wire from the zinc being 

 corroded, &c. was taken up by the alkali, and afterwards 

 depofited in its metallic form by the other wire. To the firll 

 adhered fome of the fulminating filver, and a portion was 

 alfo depofited from the fluid, after ftanding fome time. 



From pure ammonia, with copper wires, a quantity of 

 Very pure metal was precipitated — from an ammoniacal fo- 

 lution of copper the fame pure metallic precipitate. From 

 thefe experiments Mr. Cruickfhank remarks, that it appears 

 that the Galvanic influence might be employed with fuccefs 

 in the analvfis of minerals. 



Pure ammonia being introduced into a bottle, and in- 

 verted over the fame fluid, with a cork and two wires, as 

 before defcribed, (the wire conhefted with the zinc being 

 platina and the other filver), a rapid decompofition of the 

 alkali was effected. Two ounce meafures of gas being col- 

 IcAed and examined, was found to confift of 15 parts of 

 hydrogen gas, 13 of azotic, and two nearly of oxvgen gas. 



The 



