Mr Grawam on Phosphuretted Hydrogen. 105 
and has not yet been formed directly. Its existence is only sur- 
mised from the parallelism which appears to be established be- 
tween nitrogen and phosphorus, and between their compounds ; 
phosphuretted hydrogen itself corresponding with ammonia, phos- 
phoric, and phosphorous acids, with nitric and hyponitrous acids. 
The peroxide of chlorine of Davy and Stadion C corresponds 
with nitrous acid, and with our hypothetical oxide of phosphorus, 
which we may speak of as the peroxide of phosphorus. 
The peroxide of phosphorus would appear to resemble the 
peroxide of chlorine, in being acted on more slowly by mercury 
and by alkalies, than is the case with nitrous acid. It is to be 
admitted, however, that I did not succeed in producing an in- 
flammable phosphuretted hydrogen, by the agency of peroxide of 
chlorine—that there is no chlorous phosphuretted hydrogen. 
The reason is, that peroxide of chlorine is incompatible with 
phosphuretted hydrogen, reacting upon that gas the instant of 
mixture. 
As to the mode in which nitrous acid vapour, in a proportion 
so minute, contributes to the accendibility of phosphuretted hy- 
drogen, I have been able to form no distinct idea. The most 
likely conjecture is, that the nitrous acid, or resulting hyponi- 
trous acid, combines with some product of the oxygenation of 
phosphuretted hydrogen, and thereby disposes or promotes the 
occurrence of that change. The oxygenation of pure hydrogen 
itself, under the influence of a clean plate of platinum, is not 
promoted in a sensible degree by any nitrous impregnation. Sul- 
phurous acid and muriatic acid gases, and vapour of acetic acid, 
appeared to contribute nothing to the accendibility of phosphu- 
retted hydrogen. 
It appears, then, that the two phosphuretted hydrogens are 
not isomeric bodies, but that the peculiarities of the spontaneous- 
ly inflammable species depend upon the presence of adventitious 
matter : 
VOL. XIII. PART I. ‘o 
