1817.) during the Year 1816. 35 
He obtained hypophosphorous acid, which is a discovery of his 
own, in the following manner. When phosphuret of barytes, of 
strontian, or of lime, is put into water, phosphureted hydrogen gas 
is disengaged, as is well known. The oxygen of the water decom- 
posed unites to the phosphorus, and forms two acids, the hypophos- 
phorous and the phosphoric, both of which unite to the base. The 
phosphate formed is insoluble in water, but the hypophosphite is 
very soluble. He treated phosphuret of barytes in this manner ; 
and by filtrating the liquid, separated the phosphate of barytes. ‘The 
liquid contained in solution hypophosphite of barytes. The barytes 
was precipitated by means of sulphuric acid, and nothing remained 
after filtration but the hypophosphorous acid united to water. This 
acid possesses the following properties. It has a sour taste, and does 
not crystallize. [t may be concentrated by evaporation ; and ‘in 
that case we obtain a viscid liquid. When the heat is carried fur- 
ther, phosphureted hydrogen is driven off, a little phosphorus sub- 
limes, and pure phosphoric acid remains behind. It absorbs oxygen 
slowly from the atmosphere. All the hypophosphites are very 
soluble in water, Those of barytes and strontian crystallize with 
difficulty. Those of potash, soda, and ammonia, are very soluble 
in alcohol. Hypophosphite of potash is much more deliquescent 
than muriate of lime. According to the analysis of Dulong, this 
acid is composed of 
Phosphorus ........ Dat OWA DY Be Ser OD 
Mey sen ows wsiae, SE emer a icaeg:, oad: 
But he suspects that it is a triple compound, and that it contains 
hydrogen. 
Phosphorous acid was discovered by Davy. He obtained it by 
dissolving proto-chloride of phosphorus in water, and distilling off 
the muriatic acid. The phosphites have not hitherto been examined. 
They are less soluble than the hypophosphites ; but the phosphite 
of potash is deliquescent and incrystallizable, and insoluble in 
alcohol. The phosphite of soda and of ammonia are likewise very 
soluble in water. The former crystallizes in rhomboids approaching 
nearly to the cube, Those of barytes, strontian, and lime, erystal- 
lize by spontaneous evaporation ; but when their solutions are con- 
centrated by heat, small pearly crystals precipitate, similar to ace- 
tate of mercury. These crystals are subphosphites, insoluble in 
water. Superphosphites difficultly crystallizable remain in solution 
in the liquid. According to the analysis of Dulong, this acid is 
composed of 
PUUPHOREG! o siels, 5 oes 6p Aoigiederte yt a eee 
OREROU: diss pe.ctvie.s¥.0 intuladan seatee Leaee 
Phosphatic acid is obtained when phosphorus is allowed to burn 
slowly in the open air. M. Dulong considers it as a combination 
of phosphorous and phosphoric acids. According to him, it is 
always constant in its proportions. He considers it as composed of 
c ” 
