of the combinations of phosphorus* 331 
and the quantity of phosphorus in phosphuretted hydrogen 
known ; it is very easy, from an accurate experiment on the 
decomposition of the hypophosphite of baryta, to learn the 
composition of hypophosphorous acid. 
I made two experiments on this subject ; in one, 50 grains 
of dry hypophosphite of barytes were used, and the distilla- 
tion conducted in a small glass tube. About 23.25 cubical 
inches of gas were produced. The loss of weight of the 
apparatus could not be ascertained, as unluckily a little of the 
phosphate was lost ; a small portion of phosphorus was de- 
posited in the upper part of the tube, from the decomposition 
of a minute quantity of the bi-phosphuretted gas ; but this 
could not have equalled the of a grain, as the tube only 
lost T 4 - by being heated to whiteness. 
In the second experiment, 29 grains of the hypophosphite 
were used, and the loss of weight only ascertained, which 
was 3.5 grains. To be able to form any opinion as to the 
composition of the hypophosphorous acid, it was necessary 
to ascertain the composition of the phosphate of baryta pro- 
duced in these experiments; which was easily done by 
precipitating a given quantity of the hypophosphite of 
barytes by sulphate of soda in solution. 15 grains of hypo- 
phosphite of barytes, in an experiment very carefully made, 
afforded 11.3 of sulphate of barytes. Now, supposing this 
sulphate of barytes to contain 7.4 of baryta, the hypophosphite 
would consist of 7.4 of baryta, and 7.6 of hypophosphorous 
acid; and 13.1 of the acid phosphate of baryta, formed from 
its decomposition, would contain 5.7 phosphoric acid, and 7.4 
baryta. And in the experiment in which 29 grains of hypo- 
phosphite of baryta were decomposed, supposing the whole 
mdcccxviii. X x 
