382 



SCIENTIFIC NEMl. 



Mistake of 

 Fourcroy. 



Partly reduced 

 to n liquid by 

 cold. 



Its properties. 



Effects on 

 feluod. 



Action with 

 regents. 



Absorbed by 

 water only 

 when contain- 

 ing air. 



J. fleets t>f com- 

 bustion with' 

 different pro- 



gas evolved, when the tin of the shops is dissolved in mu- 

 riatic acid, is not a compound of tin and hidrogen, as 

 Fourcroy conjectures in his Chemical System, Vol. VI, 

 p. 43, (English Ed.) but of arsenic and hidrogen. When 

 arsenicated hidrogen gas is formed in the manner directed 

 above, a very pure oximuriate of tin is obtained. 



Though the arsenicated hidrogen gas retains its aeriform 

 state under every known degree of atmospheric tempera- 

 ture and pressure, prof. S. condensed it so far as to reduce 

 it in part to a liquid, by immersing it in a mixture of snow 

 and muriate of lime, in which several pounds of quicksilver 

 had been frozen in the course of a few minutes. 



The smell of this gas, he says, is not alliaceous, as has 

 been said, though in the highest degree fetid and nau- 

 seating. Warm blooded animals, particularly birds, were 

 killed in a few minutes in an atmosphere containing one 

 tenth of this gas : but frogs and insects lived in it two or 

 three hours. Blood fresh drawn from a vein became black 

 after standing a few minutes in contact with it ; and in six 

 or eight hours a layer of reduced arsenic was visible on its 

 surface. The rise of the fluid in the jar likewise proved, 

 that absorption had taken place : but no such change ap- 

 peared in blood exposed to pure hidrogen gas. Neither 

 sirup of violets, infusion of litmus or turmeric, nor paper 

 stained with them, had its colour in the least altered by the 

 gas. Infusion of galls, and alkaline sulphurets or hidro-' 

 snlphurets, have no observable action on it. It is not ab- 

 sorbed by alkalis ; and scarcely in any perceptible degree 

 by distilled water, particularly if freed from air as much as 

 possible by long ebullition. If however the water contain 

 atmospheric air, or if the arsenicated hidrogen gas be 

 mixed with atmospheric air, not only absorption but de- 

 composition takes place, part of the hidrogen and of the 

 arsenic combining with oxigen so as to form water and 

 brown oxide of arsenic, and part appearing in the form of 

 pure hidrogen gas and metallic arsenic. Hence it is, that, 

 as Proust observed, ajar in which this gas is kept over 

 water will acquire a coating of arsenic and its oxide. 



The arsenicated MdVogen gas burns in contact with at- 

 mospheric air, and a thin coat of arseuious acid and brown 



oxide 



