33 2 Sir H. Davy’s new experiments on some 
loss of weight to be owing to perphosphuretted hydrogen 
given off, and this gas to be composed of 22. 5 of phosphorus 
to 4 of hydrogen, or of 5.29 hydrogen to 29.76 phosphorus, 
and the 25.5 of acid phosphate remaining composed of 14.47 
baryta nearly, and 11.03 phosphoric acid, adding the 29.76 of 
phosphorus to the 4.72 in the phosphoric acid, and subtracting 
39, the quantity of oxygen required to form water with the 
3.24 of hydrogen, the hypophosphorous acid maybe conceived 
to be composed of 7.69 phosphorus, and 2.54, which denotes 
rather less than half the oxygen in phosphorous acid : i. e. 
as 7.43 to 1.5, an approximation nearer than could have been 
expected. 
Assuming the composition of the phosphuretted gas to be 
what is stated in the preceding page, which agrees very 
nearly with an experiment which I formerly made, the first 
experiment on the quantity of gas disengaged would give a 
proportion of oxygen rather less than that which has been 
just calculated upon; but it must be remembered, that a certain 
quantity of common phosphuretted hydrogen is produced, 
which containing less hydrogen in a given volume, would 
sufficiently explain the difference of result. 
M. Dulong has advanced an ingenious opinion, that the 
hypophosphorous acid may be considered as a triple compound 
of hydrogen, oxygen, and phosphorus. There is another view 
which may be taken of its composition, namely , that it may be a 
compound of phosphoric acid and perphosphuretted hydrogen. 
Phosphuretted hydrogen, as may be deduced from some ex- 
periments of M. Dulong, has the properties of a very weak 
alkali ; and when expelled from the neutral hypophospliites, 
they become acid. This view agrees very well with the equi- 
