PHOSPHURETS. 443 



2> Hydro-phosphoric gas. Davy ; bi-hydroguret of phosphorus. 

 Thomson. 



(a.) Obtained by heating solid phosphorous acid away from air ; 

 the hydrogen of the water of crystallization unites with a part of the 

 phosphorus to form this gas, and the oxygen with another part to 

 form phosphoric acid. 



(b.) JL distinct gas, not spontaneously inflammable ; smell fetid, 

 but less so than that of the phospburetted hydrogen. 



c.) JLt 300 Fahr. it detonates violently with oxygen gas. 

 ) Explodes in chlorine with a white flame. 



Water absorbs j- of its volume. 



/.) Sp. gr. .87* more than twelve times as much as that of hy- 

 drogen gas. 



(g.) Potassium heated in it becomes a phosphuret, and the volume 

 of the gas is doubled. 



(A.) Sulphur in the same manner produces sulphuretted hydro- 

 gen gas, equal to twice the original volume. 



(i.) 3 volumes of this gas condense 5 of oxygen, 1 volume re- 

 quires 2 of oxygen for its complete combustion, 1 for each of its 

 constituent principles, forming phosphoric acid ; and with 1 J vol. 

 oxygen, phosphorous acid. 



(j.) 1 volume of this gas absorbs 4 of chlorine. 



Remarks. Mr. Dalton says that there is only one variety of the 

 phosphuretted hydrogen, that the others quoted are merely mixtures 

 of this with common hydrogen, and that they may be separated by 

 chloride of lime, which absorbs the former. He says that phosphu- 

 retted hydrogen requires 2 volumes of oxygen for saturation, and 8 

 volumes of water for its solution, f &c. 



It is inconsistent with the design of this work to discuss the views 

 of different writers on the subject of these compounds, particularly 

 the elaborate researches of M. Dumas. { A full abstract of them is 

 given by Dr. Ure, in his Dictionary, 2d Ed. p. 658, and the views 

 of Prof. Rose are briefly stated by Dr. Turner, 2d Ed. of his 

 Chemistry, p. 355. It is sufficient for the general student to know 

 that there are either several varieties of phosphuretted hydrogen, or 

 that the gas which has been so long known by that name, is mixed 

 in different proportions with common hydrogen gas, which as al- 

 ready stated, is the opinion of Mr. Dalton. 



* Davy. .9653 Thomson. Theory would give it at .9721 ; twice the sp. gr. of 

 hydrogen, = 0.1388,+ sp. gr. of phosphorus vapor, 8333. .9721. Henry. Mr. 

 Dumas states it as 1.214. 



t Thomson's Annals, Vol. XI, p. 7. 



i Ann. dc Chirn. et de Phys. Vol. XXXI, p. 158-. 



