According to Dulong, when the earthy phosphurets are decomposed by water, phosphuretted hydrogen and subphosphorous acid are formed. I believe this determination is right; for I find at most only ⅓ of the above proportion of phosphorus in the phosphuretted hydrogen yielded by 10 grains of the phosphuret of lime; the remaining ⅔ seem to rest in the liquid in combination with the oxygen and lime; that is, 1 atom of hydrogen combines with 1 of phosphorus, and 1 of oxygen with 2 of phosphorus. Notwithstanding this, the phosphoric acid produced from the residue by means of oxymuriate of lime, does not in general correspond to the above quantity. Perhaps this loss may be owing to the phosphorus carried over in mechanical suspension by the gas. M. Dulong observes, that even the earthy subphosphites are very soluble; this did not appear to me to be the case with that of lime: 10 grains of phosphate of lime, that had been exposed for 20 minutes to the air, were put into a gas bottle filled with 400 grains of water; this was kept at nearly the boiling heat for an hour, when 725 grain measures of gas were produced, and some phosphorus was carried over with it into the receiving bottle and bason of water. The gas being analysed, was found to consist of 62 per cent. phosphuretted hydrogen, 33 hydrogen and 5 common air. The 400 grains of water in the gas bottle treated with oxymuriate of lime, and then with lime water, scarcely gave any appreciable quantity of phosphate of lime. The insoluble residue when dried yielded 9 grains. This dissolved in muriatic acid left a fraction of a grain of dirty yellow powder, which indicated some phosphorus; and the muriate of lime indicated about 6 grains of lime. _5. Phosphuret of barytes._