208 ARSINEATKD HIDROCEN CAS. 



Ammoniate of copper, on being mingled with it, acquired 

 a greenidi colour. Hydrofulphuret of ammonia inftantly oc- 

 cafioned a copious yellow precipitate. 



Water impregnated with fulphurafed hidrogen gas, occa- 

 fioned a fimilar effect. From the refults of thefe tefts it be- 

 comes obvious, that the acid confifted of fulphuric, ful- 

 phureous and arfenic acid. In order to be certain in this 

 refpe6t, I mingled a few drops of liquid arfenic acid with a 

 mixture of fulphuric and fulphureous acid, neutralized the 

 fluid with ammonia, and fubmitted it to the fame tefts. The 

 theory. refults of this mixture were analogous to the /ormer. The 



decompotition of the arfeniated hidrogen gas, is probably 

 analagous to the decompofition of this gas, by means of 

 oxiginized muriatic acid ga.«, .The fulphuric acid firft gives up 

 part of its oxigen to the hidrogen of the arfeniated gas, and 

 occafions the feparation of the arfenic ; which, at the ex- 

 pence of the remaining portion of oxigen of the fulphuric 

 acid, becomes afterwards oxigenized, and conftitutes the 

 arfenic acid. 



Its habitudes Habitudes of arfeniated Hydrogen Gas to Metallic Solutions. 



folutions. 1 caufed a current of arfeniated hidrogen gas, to pafs through 



Ammoniate of ^ foJution of ammoniate of copper. , A metallic pellicle ap- 

 peared on the furface of the fluid, which fuflTered no other 

 change. 



Muriate of tin. Into a botlle filled with arfeniated hidrogen gas, I dropped 

 a folution of muriate of tin. On agitating the folution, it ac- 

 quired a brown colour, a partial diminution of the gas en- 

 fued, but the folution of tin was not converted into an oxi- 

 dized muriate of tin, which would have been the cafe, if 

 the arfenic exifted in the gas in an oxidized ftate. 



Nitrate of lead. Nitrate of lead, on being brought into contaft with ar- 

 feniated hidrogen gas, became turbid, and depofited a preci- 

 pitate, which was arfeniate of lead. 



Nitrate of filver. Nitrate of filver fubmitted to the action of the ga?, became 

 inftantly of an intenfe black, and a pellicle of metallic filver 

 coUefled on the furface of the fluid. The refidue of the gas, 

 which had been made to a6t on the oxide of filver for fome 

 tin.e, had all the properties of pure hidrogen. 



A good teft. This experiment fiiows, that nitrate of filver might be em- 



ployed for detecting the prefence of arfeniated hidrogen ; for 



