ON ANTIMONIURETTED HYDROGEN, ETC. 
217 
ART. XXXIV. — COMPARATIVE EXAMINATION OF ANTI- 
MONIURETTED AND ARSENIURETTED HYDROGEN, AND 
UPON THE NEW MODES OF REDUCING THE SULPHU- 
RET OF ARSENIC. By J. F. Simon.* 
The interesting discovery of antimoniuretted hydrogen, 
made at the same time by MM. Thompson and Pratt, renders 
very uncertain the method of Marsh for the discovery of 
arsenic. 
I prepared these two gases by adding to a mixture of very 
pure zinc and diluted sulphuric acid, a solution of arsenious 
acid and of tartar emetic. The following are the characters 
which I recognised: 
1. Antimoniuretted hydrogen, heated in a glass tube, is 
decomposed like arseniuretted hydrogen, and gives a metallic 
coating, but which is more silver white than that of arsenic. 
In very thin films, the antimony appears of a deep gray, and 
the arsenic of a deep brown. The flame of the two gases in 
combustion is identical. 
2. Neither gas is absorbed by water. 
3. Solutions of potassa, ammonia, and nitric acid, have no 
action upon them. 
4. A solution of chlorine decomposes antimoniuretted hy- 
drogen, and, at the commencement, retains nearly all the 
antimony in solution, but at the end of some time deposits it 
in white flocculi, and the solution becomes very acid. A 
similar reaction takes place with arseniuretted hydrogen, with 
this difference, that with this latter gas no precipitate is 
formed, the arsenic remaining in solution in the state of arse- 
nious acid. 
5. A solution of iodine in alcohol decomposes both gases, 
and, at the end of a certain time, becomes totally discolored. 
With the antimoniuretted hydrogen, it forms brown flocculi, 
and none of the antimony remains in the solution. With 
* Ann. de Pog., t. 42, p, 563, 
