Chemical Science. 177 



sensibly the same result if an excess of phosphuretted hydrogen gas 

 were employed. Heated in the same way with very dry chloride of 

 mercury, for 100 parts of the gas there were obtained 300 parts of 

 muriatic acid gas, entirely soluble in water. The protophos- 

 phuretted hydrogen gas heated with great excess of pure oxygen, 

 easily inflames and burns with an extremely vivid and almost in- 

 supportable light ; so that it may be concluded, that all the phos- 

 phorus is changed into phosphoric acid ; finally the residue, after 

 many experiments, when collected together, did not discolour the 

 red manganesiate of potassa. 25*25 measures of phosphuretted 

 hydrogen, gradually burnt with 190 measures of oxygen, left a 

 remainder of 139*5 measures of gas. In another experiment, 27 

 measures of phosphuretted hydrogen were decomposed by 160*75 

 measures of oxygen; there remained 101*75 of oxygen. These ex- 

 periments evidently shew that 100 volumes of protophosphuretted 

 hydrogen gas, to be completely decomposed, require 200 volumes 

 of oxygen. All this proves that non-inflammable phosphuretted 

 hydrogen gas contains once and a half its volume of hyrodgen, and 

 the half of its volume of phosphorus vapour, a result which agrees 

 with that of M. Dumas. 



ii. Phosphuretted Hydrogen. 

 The gas examined was obtained from the decomposition of phos- 

 phuret of lime by water. It is very easily dissolved in sulphate of 

 copper; but 100 parts have constantly left from 13*5 to 14*5 of 

 insoluble gas. By heating it in a graduated bell-glass, it deposits 

 phosphorus without changing its volume ; but it ceases to burn in 

 air, although it retains the property of dissolving in sulphate of 

 copper. It decomposes very easily even at the ordinary tempera- 

 ture of the air, and sometimes at the very moment of its formation, 

 so that there is no certainty of having it pure. Heated in a curved 

 bell-glass with metallic copper, it increases its volume one half, like 

 the preceding gas. This gas, mixed with three times its volume of 

 carbonic acid, burns perfectly well in oxygen, and in air, and with- 

 out leaving the least trace of phosphorus. In oxygen in great ex- 

 cess, it burns with a vivid and brilliant light almost like phosphorus ; 

 but in air, the light is much less brilliant, and in the end it becomes 

 pale and bluish. In this last case, it is probable that there is 

 formed a mixture of phosphoric and of phosphatic acid ; but with 

 oxygen in very great excess, the result is pure phosphoric acid. 



Given quantities of phosphuretted hydrogen gas have been several 

 times decomposed in oxygen in the manner stated ; but the results of 

 these different experiments do not agree very well with each other. 

 100 volumes of pure phosphoretted hy- 

 drogen have combined with . . 204 of oxygen. 



100 270 



100 226 



100 240 



100 230 



100 232 



JULY— SEPT., 1829. N 



