Mr. Davy’s Researches on 
256 
bably connected with the production of water. Though the 
pure oxides of sulphur and phosphorus have never been 
obtained, yet from the doctrine of definite proportions, these 
bodies ought, under certain circumstances, to be formed. 
And I am inclined to believe, that they sometimes exist in 
minute quantities, in common phosphorus and sulphur, and 
with hydrogene, give to them their variable properties. 
The colours of different specimens of phosphorus, as well as 
of sulphur, differ considerably ; the red colour of phosphorus 
as it is commonly prepared, is probably owing to a slight 
mixture of oxide. Common roll sulphur is of a very pale 
yellow, the Sicilian sulphur of an orange colour, and the sul- 
phur distilled from iron pyrites in vacuo, which arose in the 
last period of the process, of a pale yellowish green colour. 
All the late experiments that I have made, as well as my 
former researches, induce me to suspect a notable proportion 
of oxygene in Sicilian sulphur, which is probably owing to 
the presence of oxide of sulphur, which may give rise to sul- 
phuric acid in distillation, or to sulphuric acid itself. 
Conceiving that if definite proportions of oxygene and hy- 
drogene existed in sulphur and phosphorus, they ought to be 
manifested in the agency of oxymuriatic acid gas, on these 
bodies, I made some experiments on the results of these 
operations. In the first trial, on the combination of sulphur 
with oxymuriatic acid gas, I employed 5 grains of roll sulphur, 
and admitted the gas into the exhausted retort, from a vessel 
in which it had been in contact with warm water : in this 
case more than a half a cubical inch of oxygene gas, and 
nearly two cubical inches of muriatic acid gas, were produced. 
•Suspecting in this instance, that aqueous vapour had been 
