Intelligence and Miscellaneous Articles. 483 



tion was set aside, and the gas disengaged from the apparatus was 

 passed through a fresh solution, which became immediately turbid, 

 and gave in a few minutes a very evident precipitate ; when the ap- 

 paratus was uncorked, M. Filhol was surprised on finding that the 

 gas disengaged had the odour of hydrosulphuric acid : the operation 

 was discontinued till the next morning, and the current of gas was 

 then passed into a third solution of nitrate of silver, which became 

 immediately turbid ; in a few minutes nearly the whole of the silver 

 was precipitated, the gas emitting a strong smell of hydrosulphuric 

 acid. 



The author states he always employed very dilute sulphuric acid, 

 in order to avoid the production of hydrosulphuric acid pointed out 

 by MM. Fordos and Gelis. 



The black precipitates obtained, evidently contained sulphuret of 

 silver, but it was possible that arseniuretted hydrogen might also be 

 disengaged, independently of the hydrosulphuric acid ; to ascertain 

 this hydrochloric acid was added to each solution, the chloride of 

 silver was separated by filtration, and the filtered liquids were treated 

 with hydrosulphuric acid ; in all of them a yellow precipitate was 

 formed, which was found to be sulphuret of arsenic. 



M. Filhol is of opinion that from these experiments he may con- 

 clude that the natural sulphurets of arsenic are not absolutely unacted 

 upon in Marsh's apparatus, as hitherto supposed ; that they are very 

 slowly decomposed, and that the quantity of arsenic brought over by 

 the hydrogen is too small to produce arsenical spots ; that it requires 

 a long time to ascertain its presence in the metallic solutions which 

 have retained it ; that nascent hydrogen acts on both elements of 

 these sulphurets, and always contains traces of hydrosulphuric acid 

 and arseniuretted hydrogen. 



The author observes that M. Chevallier's experiments on the natu- 

 ral sulphurets of arsenic are nowise in opposition to the preceding 

 facts, since the washings of the sulphurets in the experiments of 

 M. Chevallier contained traces of arsenious acid, which M. Filhol's 

 did not ; and he thinks the slowness of the action on the sulphurets 

 of arsenic will account for their having been supposed to be not 

 acted upon at all. 



From the experiments detailed the author is of opinion, that 

 though he has not succeeded in rigorously demonstrating the pre- 

 sence of arsenic in the cases alluded to, he has shown that it may 

 exist in the state of sulphuret in the deposits of certain natural 

 chalybeate waters, and that it ought to be searched for in those which 

 contain sulphates ; the same remark applies to the searches for arsenic 

 in the earth of cemeteries. — Journ. de Chim. Me"d., Octobre 1848. 



ANALYSES OF DIFFERENT VARIETIES OF EPIDOTE. 

 BY M. HERMANN. 



The author has subjected to analysis a great number of the varie- 

 ties of epidote, such as zoisites, pistazites, orthites, &c, found in part 

 in the Ural. 



Zoisites — Grey zoisite from Falltigel in the Tyrol ; density, 3"28. 

 Imbedded in granite. 



