Into 800 grains of phosphuretted hydrogen water containing 20 grain measures of gas, were put by degrees, 22 grain measures of muriate of palladium (sp. gr. 1.01) containing .12 acid and .14 oxide, corresponding to .12+ metal; mutual saturation was produced, and a finely distinct black powder precipitated, leaving the water clear and colourless, which was found by lime water to contain .12 parts of a grain of muriatic acid. The black powder collected and dried, corresponded as nearly as could be determined in weight to the ingredients. Now 20 measures of gas would weigh .025 of a grain, of which .0025 would be hydrogen and .0225 phosphorus; whence we have .12+ metal joined to .0225 phosphorus or 50 to 9 nearly, indicating one atom of each. Hence 100 palladium would take 18 or 19 phosphorus. 12. _Phosphuret of copper._ M. Pelletier combined copper and phosphorus by the same means as the preceding compounds. One hundred grains of copper united by heat with 15 of phosphorus; the fused mass when cooled was white and very hard. As part of the copper gets oxidized during the process he thinks it probable, with M. Sage, that copper may acquire 20 per cent. of phosphorus. In the 3d VOL. of Memoirs of the Society of Arcueil, page 432, M. Dulong converts fine copper wire into phosphuret by heating it to a low red, and passing the vapour of phosphorus over it in hydrogen gas. In the sequel he observes that 10 grammes of phosphuret of copper contained 1.97 of phosphorus; that is, the copper was to the phosphorus as 8.03 ∶ 1.97, or as 100 ∶ 24.5. This exceeds much Pelletier’s result, and is, I think, too high. For, he found that the above phosphuret converted into phosphate of copper by nitric acid yielded 14.44 grammes. Now supposing the atom of phosphorus to weigh 9⅓, that of phosphoric acid 23⅓, and that of the black oxide of copper 70, we have an atom of phosphate of copper = 93⅓: and if 93⅓ ∶ 9⅓ ∷ 14.44 ∶ 1.444, for the phosphorus in 10 grammes; and hence the copper would be 8.556: this would give 100 copper to 17 phosphorus nearly, which would accord well with Pelletier’s determination, and very nearly agree with the theoretic result of 100 copper to 16⅔ phosphorus. Both Raymond and Thomson remark that phosphuretted hydrogen water produces a black or dark brown precipitate in sulphate of copper. I have not found any precipitate from any of the salts of copper by the same means. But if the blue hydrate be first precipitated by lime water, and then the phosphuretted hydrogen water admitted, the hydrate is immediately converted into a dark olive, which in all probability is a phosphuret of copper. From some experiments I am inclined to believe that this compound is the deutophosphuret, or two atoms of phosphorus to one of copper; and hence the copper is to the phosphorus as 100 ∶ 33⅓. 13. _Phosphuret of iron._