NOTES ON THE THEORY OF DISSOCIATION OF GASES. 217 
expression of the dissociation taking place, we ought to extend 
similar reasoning to the cases examined by Regnault. In other 
words, we cught to admit that gases formed with condensation may 
undergo a measurable dissociation, though it may not be appreci- 
take the case of a gas like nitrous oxide, for instance, Regnault’s 
ear as ee oe by Berthelot and Orgier, point either 
small dissociation into the elements oxygen and nitrogen, or 
ate a resolution of NO, molecules into N 2 molecules—or both 
dissociable gases examined by Berthelot and Orgier, ‘and gases 
whose dissociation like that of hydrogen or oxygen is too small 
to be appreciable. 
Mr. . RussEvt, in proposing a vote of thanks to Professor 
Threlfall, said: That the Professor had taken up a subject which 
is of the utmost importance to all scientific men, quite as much to 
) 
to take a view other than that favoured by neem ‘Threlfall as to 
the rate of expansion of the gases referred to. We know very 
little of the condition of the gases we find 3 nature. It had 
occurred to him as feasible that gases are subject to such variations 
of their component parts as are known in regard to matter; as 
sulphur which possesses different conditions according to the state 
in which it is at the time-being 
Professor THRELFALL, in reply, stated that he yeeros that the 
more correct way to proceed would be first to obtain reliable 
information as to gases, and afterwards apply the knowledge thus 
gained to solids and not vice vers 
[One Diagram. ] 
