of Phosphorus and Sulphur, &c. 409 
was sublimed in the gas over mercury, the volume was like- 
wise doubled ; a compound of phosphorus and sulphur was 
formed, and the elastic fluid produced had all the characters 
of sulphuretted hydrogene. 
It appears from these experiments, that the peculiar gas 
consists of 4.5 of hydrogene in weight to 32.5 phosphorus ; 
and its composition being known, it is easy to determine the 
composition of the hydrophosphorous acid, and likewise the 
quantity of oxygene required by a given quantity of phospho- 
rous acid to be converted into phosphoric acid ; for, for every 
volume of gas disengaged, a volume of oxygene must have 
been fixed in the phosphoric acid. 
And calculating for 174 grains, 30 parts of oxygene must 
be fixed in the 1 50 parts of phosphoric acid, and 20 parts of 
phosphorus disengaged in combination with 4 parts of hydro- 
gene ; and on the idea of representing the proportions in 
which bodies combine by numbers, if hydrogene be considered 
as unity and water as composed of two proportions of hydro- 
gene, 2, and one of oxygene 15,* phosphorus will be repre- 
sented by 20. 
When the compounds of chlorine and phosphorus are acted 
on by a small quantity of water, muriatic acid gas is disengaged 
with violent ebullition, the water is decomposed, and it is evi- 
dent that for every volume of hydrogene disengaged in com- 
bination with the chlorine, half a volume of oxygene must be 
combined with the phosphorus ; and the products of the mu- 
* Supposing 100 cubical inches of the gas to weigh 27 grains. — 27 4.5 the 
weight of 200 cubical inches of hydrogene — 22.5 grains. 
f This mode of estimation is the same as that I have adopted on a former occasion, 
except that the number representing oxygene is doubled to avoid a fractional part. 
