Sulphur and Phosphorus. 255 
portion of sulphur, and 2 of oxygene ; and these estimations 
do not differ from each other materially. 
I have made several experiments on the combustion of 
phosphorus in oxygene gas. From the most accurate, I am 
inclined to conclude that 25 of phosphorus absorb in combus- 
tion about 34, of oxygene in weight ; and considering phos- 
phoric acid as composed of 3 proportions of oxygene and 1 of 
phosphorus, the number representing phosphorus will be 
about 16.5, which is not very remote from the number that 
may be deduced from the composition of phosphoret of 
potassium. 
The numbers which represent the proportions in which 
sulphur and phosphorus unite with other bodies, are such, as 
do not exclude the existence of combined portions of oxygene 
and hydrogene in their constitution ; but it may be questioned, 
whether the opinion which I formed, that the inflammable 
gas disengaged from them by electricity, is necessary to the 
peculiar form in which these bodies exist, is not erroneous. 
Phosphorus, as I have stated in the last Bakerian lecture, is 
capable of forming a solid hydruret : and a part of the sulphur 
distilled from iron pyrites, is usually of a soft consistence, and 
emits the smell of sulphuretted hydrogene, and probably con- 
tains that body. It is not unlikely, that in all cases, phosphorus 
and sulphur contain small quantities of the hydrurets of phos- 
phorus and sulphur ; and the production of a minute portion 
of sulphuric acid in the slow combustion of sulphur, is pro- 
hydrogene at 35 grains, the 100 cubical inches, which was not far from the mean, 
between the estimations of Mr. Kir wan and Mr. Thenard, According to this 
last experiment, sulphuretted hydrogene is composed of 1 proportion of hydrogene, 
represented by 1, and 1 of sulphur represented by 13.4. 
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