ARSHNIATED HJDROGEN GAS. 205 



Kiitted, a divifion of hidrogen muft take place, in the follow- 

 ing manner; one part of it rnuft unite with the oxigen of the 

 oxiginized muriatic acid gas, to produce water; another part 

 mufl fall down with the arfenic; and another portion remains 

 combined with caloric, in the form of hidrogen gas. 



Hydrothian acid gas * and arfeniated hidrogen do not zSt Sulphurated and 

 upon each other. To a mixture of equal parts of hydrothian^'"^^"'^^^'^^''*"- 

 acid gas, and arfeniated hidrogen gas, I added gradually <^x- Oxiginized mu. 

 iginized muriatic acid g'.i; a diminution of volume inftantly '"'^'''^ ""='«* S" 

 look place, accompanied with liberation of heat, and a depo- 

 filion of yellow fulphurized arfenic (orpiment). On adding 

 an additional quantity of gas, the precipitate acquired a beau- 

 tiful orange red colour, and on continuing the addition of ox- 

 iginized muriatic acid gas, white clouds were produced, the 

 precipitate detached itfelf from the fides of the vefTel, and 

 were gradually converted into a pulverulent fubftance of a yel- 

 lowilh white colour. 



The refults of thefe experiments are obvious, and might Teft of arfen<» 

 , have been expeded a priori. But they may ferve as a teft to*^^'* hidrogen. 

 difcover the prefence of arfeniated hidrogen, when contained 

 in other gafes. 



I mingled one cubic inch of arfeniated hidrogen with ten of Nitrogen mixe4 

 nitrogen, and one of hydrothian acid (fulphurated hidrogen ^"^ "• 

 gas;) on adding to this mixture a fmall quantity of oxiginized 

 muriatic acid gas, yellow fulphurized arfenic was inftantly de- 

 pofited. It is not improbable, that arfenic is likewife foluble 

 in other gafes, and in this cafe the hydrothian acid (liquid ful- 

 phurated hidrogen,) in conjunction with oxiginized muriatic 

 acid, would prove a ufeful re-agent for difcovering the prefence 

 of it. 



A lighted taper immerfed in a vial filled with arfeniated hi- Extinguiftes a 

 drogen, is inftantly extinguiflied; at the fame time that the {,^j i^^^^" J' 

 gas burns at the orifice of the vial with a lambent white flame, 

 diffufing a difagreeable odour, and much white fumes, which 

 are arfenious acid. If the gas be inflamed in a phial with a 

 fmall orifice, the flame defcends gradually down to the bottom 

 of the phial, which becomes lined with a coat of cryflallized 

 metallic arfenic. In this cafe therefore the hidrogen alone 

 burns. 



* The name given by the Germans to fulphurated hidrogen gas, on 

 account of its pofiefEng the pioperties of an acid. 



If 



