352 
DR. DALTON ON THE CONSTITUTION OF THE ATMOSPHERE. 
and that when a sulphuret is dissolved in water, no sulphate is ever formed, as is 
commonly imagined, but sulphites and sulphuretted sulphites. Some proofs are after- 
wards given*. Vauquelin, in the 6th volume of the Annales de Chimie et de Phy- 
sique, 1817, presents us with a laboured series of experiments on the alkaline sul- 
phurets, the chief object of which is to ascertain the state of the alkali in the sulphuret, 
whether it is that of a metal or of an oxide. After many experiments on the sul- 
phurets of potash, soda, and lime in the dry way, and one on sulphuret of lime in 
the humid way, the author sums up, and notwithstanding his leaning to the opinion 
that the alkalies exist in sulphurets in the state of metals , he is obliged at last to ac- 
knowledge “ that it is probable, but not yet demonstrated , that in all the sulphurets 
formed by means of the alkaline oxides by a red heat, these last lose their oxygen, 
and are united to sulphur in the metallic state, as is the case with the other metals.” 
Gay-Lussac, in the sequel of the same volume, page 322, in a memoir, animadverts 
on the before-cited paragraph ; and allowing that sulphuric acid is formed when a 
sulphuret of potash made by a red heat is dissolved in water, he contends, according 
to a suggestion of Berthollet, that the acid is formed in the instant of solution from 
the reciprocal action of the sulphuret and the water, rather than from the oxygen of 
the potash and sulphur. This opinion is countenanced by several combinations of a 
similar nature, which he has adduced, and which are worth the attention of chemists. 
Without adverting at present to my own experiments, I may observe that Sir John 
Herschel, in an essay in the first volume of the Edinburgh Philosophical Journal, 
1819, was the first writer who published an atomic view of the class of salts called 
sulphuretted sulphites, or hyposulphites, that accorded with what 1 had long enter- 
tained and demonstrated by reiterated and decisive experiments •f-. In the above- 
mentioned essay he showed clearly that the hyposulphurous acid is composed of two 
atoms of sulphur and two of oxygen, which united to one atom of base, as potash or 
lime, compose an atom of a hyposulphite. The formation of those of lime, potash, 
soda, barytes, and some metallic oxides is more particularly explained. A saturated 
solution of hyposulphite of lime at 50° he found to be L30 specific gravity^. 
In the 14th volume of the Annales de Chimie et de Physique, Gay-Lussac has given 
the principal results of Herschel’ s essays on the hyposulphurous acid with some judi- 
cious remarks, but he leaves the subject as one requiring further investigation. 
In 1822 Berzelius published a memoir on the alkaline sulphurets. The results of 
his experiments seemed to him confirmatory of the previous notion of Vauquelin. 
Those experiments were on the sulphurets of potash and lime made in the dry way ; 
he made only one on lime, which agreed very well with the theory ; but this very 
* See also vol. lxxxv. p. 199. 
t See New System of Chemical Philosophy, vol. ii. Preface, and p. 105. 
X Dr. Thomson, in a paper on the compounds of chromium in the Transactions of the Royal Society for 1826, 
disputes the accuracy of this constitution of hyposulphurous acid. I have never had any doubt concerning it 
since 1815. 
