452 New Experiments on some of 
I have mentioned in the paper to which I have referred, in 
the beginning of this communication, that the hydrophospho- 
rous acid is decomposed by heat; and that phosphoric acid, and 
perphosphuretted hydrogen are the results. In examining the 
nature of the phosphoric acid formed, I find that it contains 
water, so that it is a hydrated phosphoric acid. In carefully 
conducting the experiment, I find likewise, that a small propor- 
tion of water is given off with the perphosphuretted gas. I shall 
give the results of an experiment: 17°5 grains of hydrophos- 
phorous acid were decomposed by heat in a small glass retort 
carefully weighed; 6°5 cubical inches of elastic fluid were gene- 
rated, and the loss of the retort was four grains. ‘Now, if it be 
assumed that the hydrate of phosphoric acid * remaining equalled 
13-5 grains, and that it contained, according to the law of de- 
finite proportions, 1-88 of water, and that the bi-phosphuretted 
gas weighed 1°937, and consisted of 1°6446 phosphorus, and 
2924 hydrogen; then the oxygen in the phosphorous acid will 
be to the phosphorus as 44 to 66, which is as near a result as 
can be expected. 
For 4 proportions of phosphorous 
acid are .. .. «. «. 300 or the double 150 
Bnd LOVE Waren ke lee ya LEU or _ 85 
which together amountto .. 470 or 239 
- which form 3 proportions of phosphoric acid 315 or 157+5 
with 3 of water toformthe hydrate ..  .. 91 or 25°5 
366 183-0 
4 of water decomposed, of which the hydrogen 
is 8, to form with 45 of phosphorus phos- 
phuretted hydrogen .. 0 6. 2.0 0. oe 8 or! 265 
2 of ‘water given OP ero Oe we pe, Gehan MAS 
LATE Sata te ie AR A Neh eh ge i STE ie 
I have no doubt that the acid which I used formerly was drier 
than the acid employed in this experiment, which will account 
for the difference of the result. Supposing a hydrophosphorous 
acid could be procured, containing only the quantity of water 
sufficient to convert it into dry phosphoric acid, it would consist, 
as I have stated in my former paper on phosphorus, of four pro- 
portions of water, and four proportions of phosphorous acid. 
I have adopted throughout the whole of these calculations, 
the supposition that the hydrogen in water is to the oxygen as 
2to 15: and consequently I have taken the number represent- 
ing oxygen as 15, which is extremely convenient, as the mul- 
tiples are simple, 80, 45, 60, &c. Taking the proportion of 
* I proved it to be a hydrate by heating it with magnesia, when abun- 
dance of water was given off from it. 
phosphoric 
