ON THE OXIDES OF SULPHUR. 
243 
ART. XLIX.— ON CERTAIN FACTS RELATIVE TO THE 
OXIDES OF SULPHUR By M. Persoz. 
In a thesis, sustained seven years since before the Faculty 
of the Sciences of Paris, M. Persoz said that certain compounds, 
and especially sulphuric acid, were comparable to cyanogen, 
and might like it exercise the functions of simple bodies in 
uniting with oxygen, sulphur, chlorine, bromine or iodine ; 
under this view, sulphuric acid cannot be considered as a 
compound of sulphur and oxygen, but rather as composed of 
two volumes of sulphurous acid, and one of oxygen, and he 
was naturally induced to place the sulphurous acid, as a 
new radical, in contact, successively with different simple 
bodies, with which it might unite to produce compounds 
analogous to the binary combinations of simple bodies. M. 
Persoz had applied himself to the study of these combinations 
when the publication of M. Langlois on hyposulphurous acid 
constrained him prematurely to make known the results 
which he had obtained. 
M. Vauquelin, by acting with 8 grammes of sulphur, upon 
10 grammes of carbonate of potassa, and ascertaining the 
sulphur in each product, which he procured, could find only 
7.183 grammes. This singular observation having caused 
M. Persoz to suspect that Vauquelin had been led into error 
by the formation of an unknown compound, he repeated 
the experiments, by fusing at a red heat, 80 gr. of sulphur 
with 100 L gr. of carbonate of potassa, dry and pure. The 
matter, when cold, pulverized and subjected to alcohol of 40° 
left a pulverulent residuum, analogous in appearance to sul- 
phate of potassa. He examined the residuum, and found 
that when heated in a small tube, it gave off sulphur, and 
that treated with nitric acid, at a moderate temperature, it 
decomposed this acid and deposited sulphur ; he recognised 
at last that this salt was formed by hyposulphurous acid, and 
according to his system he denominated it sulpho-sulphuric 
