TABLE _of the Combinations of Phosphorous and Phosphoric Acids, with the Salifiable Bases, in the Order of Affinity._
_Names of the_ _Names of the Neutral Salts formed by_ _Bases._ _Phosphorous Acid,_ _Phosphoric Acid._
Phosphites of(B) Phosphats of(C) Lime lime lime. Barytes barytes barytes. Magnesia magnesia magnesia. Potash potash potash. Soda soda soda. Ammoniac ammoniac ammoniac. Argill argill argill. Oxyds of(A) zinc zinc zinc. iron iron iron. manganese manganese manganese. cobalt cobalt cobalt. nickel nickel nickel. lead lead lead. tin tin tin. copper copper copper. bismuth bismuth bismuth. antimony antimony antimony. arsenic arsenic arsenic. mercury mercury mercury. silver silver silver. gold gold gold. platina platina platina.
[Note A: The existence of metallic phosphites supposes that metals are susceptible of solution in phosphoric acid at different degrees of oxygenation, which is not yet ascertained.--A.]
[Note B: All the phosphites were unknown till lately, and consequently have not hitherto received names.--A.]
[Note C: The greater part of the phosphats were only discovered of late, and have not yet been named.--A.]
SECT. XVI.--_Observations upon Phosphorous and Phosphoric Acids, and their Combinations._
Under the article Phosphorus, Part II. Sect. X. we have already given a history of the discovery of that singular substance, with some observations upon the mode of its existence in vegetable and animal bodies. The best method of obtaining this acid in a state of purity is by burning well purified phosphorus under bell-glasses, moistened on the inside with distilled water; during combustion it absorbs twice and a half its weight of oxygen; so that 100 parts of phosphoric acid is composed of 28-1/2 parts of phosphorus united to 71-1/2 parts of oxygen. This acid may be obtained concrete, in form of white flakes, which greedily attract the moisture of the air, by burning phosphorus in a dry glass over mercury.
To obtain phosphorous acid, which is phosphorus less oxygenated than in the state of phosphoric acid, the phosphorus must be burnt by a very slow spontaneous combustion over a glass-funnel leading into a crystal phial; after a few days, the phosphorus is found oxygenated, and the phosphorous acid, in proportion as it forms, has attracted moisture from the air, and dropped into the phial. The phosphorous acid is readily changed into phosphoric acid by exposure for a long time to the free air; it absorbs oxygen from the air, and becomes fully oxygenated.