106 -Mr Granam on Phosphuretted Hydrogen. 
That the vapour of some acid of nitrogen, which, in the pre- 
sent state of our knowledge of that class of compounds, seems to 
be the nitrous acid, is capable of rendering phosphuretted hydro- 
gen spontaneously inflammable, when present to the extent of 
one ten-thousandth part of the volume of the gas: 
That the last gas has a general resemblance to phosphuretted 
hydrogen, as obtained in the spontaneously inflammable state by 
ordinary processes, which, it is probable, owes its ready accendi- 
bility to the presence of an equally minute trace of a volatile 
compound of phosphorus and oxygen, analogous to nitrous acid, 
