230 Scientific Notices— Chemistry : [Sept. 



ing cast iron in dilute sulphuric acid, and digesting the residue 

 in very strong alcohol : the solution was filtered while hot, and 

 the alcohol was distilled off with a very gentle heat. Thus ob- 

 tained, the oil was clear and transparent, had a slight lemon- 

 yellow colour, and an acrid taste. It appeared to hold a mid- 

 dle rank between the fat and volatile oils. He remarked the 

 formation of a similar oil during the solution of tin in muriatic 

 acid. — (Journal des Mines, No. cxix. p. 392.) 



Doebereiner ascertained more recently that hydrogen gas 

 may be rendered completely inodorous, by being kept in con- 

 tact for some time with newly ignited charcoal — (Schw. Journ. 

 iii. 377) — and Mr. Donovan, that the same object may be ef- 

 fected by passing the gas successively through lime water, ni- 

 tric acid, solution of green vitriol, and water. Neither of them 

 alludes to an oil as occasioning the peculiar odour : the latter, 

 indeed, ascribed it wholly to sulphuretted and phosphuretted 

 hydrogen. — (Phil. Mag. xlviii. 138.) 



Before concluding, we may observe, that although this olea- 

 ginous principle is probably formed invariably during the solu- 

 tion of the sub-carburets of iron, and also of other metals, 

 such as manganese, nickel, &c. which combine with small 

 quantities of carbon, there are besides other circumstances 

 under which the hydrogen evolved during the solution of metals 

 will possess a peculiar odour. This will take place whenever 

 the metals contain traces of phosphorus, sulphur, selenium, 

 tellurium or arsenic. The solution of those varieties of iron, 

 so common in France, which contain phosphorus, is always ac- 

 companied with the odour of phosphuretted hydrogen. Most 

 of the tin which occurs in commerce, even those refined spe- 

 cimens sold under the name of grained tin, occasion the evo- 

 lution of a considerable quantity of sulphuretted hydrogen gas 

 when dissolved in muriatic acid. We think it not improbable 

 that the doubtful compound described by Kastner and others, 

 under the name of stanniuretted hydrogen gas, is nothing else 

 than arseniuretted hydrogen ; which, of course, must make its 

 appearance whenever the tin happens to be contaminated with 

 arsenic. This would account for the prejudicial vapours which 

 are occasionally emitted during the solution of tin in muriatic 

 acid, and which are so much complained of by those who pre- 

 pare solutions of muriate of tin on a large scale, for the use of 

 the dyer and calico printer. 



3. Selenium, an Attendant of Sulphur. 

 Pleischl (in Schweigger's Neues Journ. ix. 348,) expresses his 

 opinion that selenium is not an uncommon attendant of sulphur : 

 we are inclined to think, from the observations of Berzelius, 

 Stromeyer, Gmelin, Wa'hler, Lewenau, Sec. that the fact is 

 already pretty satisfactorily established. 



