238 Intelligence and Miscellaneous Articles. 
drogen ; whilst the sulphur, at the moment of its simultaneous separa- 
tion, acts the same part as the sulphur of the sulphuretted hydrogen ; 
it combines with the deoxidized radical to form a metallic sulphuret. 
The author cites some examples in support of his process: if toa 
solution ofa neutral arseniate one of hyposulphite of soda be added 
in excess, the mixture may be heated to ebullition without producing 
any sensible change ; but if hydrochloric acid be then added, the 
arsenic is immediately precipitated in the state of sulphuret. The 
decomposition is more slow at common temperatures; but by ob- 
serving certain rules and precautions it may be rendered perfect. By 
means of this reagent results are obtained in a few minutes which 
would have required at least a day with a current of sulphuretted 
hydrogen. The decomposition of the salts of antimony and copper 
by hyposulphite of soda and hydrochloric acid, is neither less easy 
nor complete. 
The application of the hyposulphite of soda, potash or ammonia 
to the quantitative separation of metals appears to be subject to cer- 
tain principles, which may be thus stated: some metallic oxides dis- 
solve readily on an alkaline hyposulphite, when a little excess of 
alkali has been added to it; other metallic oxides are insoluble in 
it; a great number of double salts are formed, which have not 
hitherto been examined. It is thus, for example, that chloride of 
platina and potassium dissolves very readily, when gently heated, in 
hyposulphite of soda; at a boiling heat there are produced much 
sulphuret of platina and free sulphuric acid; if the hyposulphite of 
soda be in excess, and hydrochloric acid be added to it, the platina 
is completely precipitated by heat. 
It appears that the metals, which form soluble sulphur salts, are 
those which the hyposulphite of soda dissolves readily, and the dis- 
solving action exerted by hydrosulphate of ammonia partially decom- 
posed by the sulphuret of antimony, arsenic, &c., and which is in- 
comparably more energetic than that of pure hydrosulphate of am- 
monia, may be attributed rather to the hyposulphite of ammonia 
which exists in it, than to a higher degree of sulphuration. 
It may be added generally, that the metals which sulphuretted 
hydrogen is capable of precipitating from their solutions in an acid, . 
may also be precipitated by the hyposulphites. There are, however, 
some peculiar exceptions, as cadmium and bismuth for example, 
which will admit of the separation of some metals of this group from 
each other. In the third place, those metals which sulphuretted 
hydrogen does not precipitate from solution in acids, are not pre- 
cipitated by hyposulphurous acid. 
As to the acidifiable metals, it is with regard to them that the re- 
ducing power of hyposulphurous acid acts with the greatest energy : 
but the experiments of the author have been hitherto confined to 
antimony and arsenic; he proposes however to continue his re- 
searches.—Journal de Pharmacie, Novembre 1842. 
