Mr Graham on Phosphuretted Hydrogen. 89 



alike, and yet possessing different properties, if established, would 

 afford a firm basis for this doctrine. 



It was the importance of the theoretical results which might 

 be looked for, that induced me to attempt to continue the inves- 

 tigation beyond the point to which it had been carried by Rose. 



Holding the general doctrine of Isomerism as problematical, 

 my inquiries were directed to the discovery, in one or other of 

 the gases, of some adventitious matter, to the presence of which 

 the peculiarities of the species might be attributed. 



It is to be understood that the spontaneously inflammable gas 

 made use of in my experiments, was prepared by the well-known 

 process of heating phosphorus, lime and water together. This 

 gas is spoken of as " the self-accendible gas," or as " the gas 

 from phosphuret of lime." The other gas, which is not sponta- 

 neously inflammable, was prepared by heating hydrated phospho- 

 rous acid, or by allowing the preceding species, contained in low 

 receivers, to stand over water for twenty-four hours. It is de- 

 scribed as " the non-accendible gas," " the gas from phosphorous 

 acid." The ascendibility of the gas was judged of by allowing it 

 to escape in bubbles into the air from the receiver containing it, 

 either over water or mercury. The experiments were all made 

 when the temperature of the atmosphere was between 60° and 

 70° Fahrenheit. 



1 . In the process by which the self-accendible gas is procured, 

 free phosphorus distils over, of which a trace, in the state of va- 

 pour, may well be supposed to remain in the gas for some time. 

 Hence the idea has generally presented itself, that the free and 

 highly accendible phosphorus present may be the cause of the 

 spontaneous inflammability of the gas. Dr Dal ton, who all along 

 maintained the opinion, which has finally been established by 

 Rose, that the two gases are of the same composition, was in the 

 habit of referring the spontaneous inflammability of the one spe- 

 cies to this cause. The speedy loss of the property in question, 

 in the case of gas confined over water, seemed to favour this view. 



VOL. XIII. PART I. M 



