TRANSACTIONS 



OF THE 



ROYAL IRISH ACADEMY 



I. Upon a new Method of investigating the Specific Heats of the Gases. 

 By James Apjohn, M.D., M.R.I.A., Professor of Chemistry in the Royal 

 College of Surgeons, Ireland. 



Read 16th March, 1837. 



There is scarcely a problem within the range of experimental physics, 

 which, in modern times, has attracted so much attention as that which has 

 for its object the determination of the specific heats of what are sometimes, 

 though improperly, called the permanently elastic fluids. It is a problem, also, 

 encompassed by so many difficulties, that the best results hitherto obtained are 

 usually considered but as approximations ; and the simple law to which the more 

 recent results would appear to point, that under equal volumes all gases have the 

 same specific heat, is, it is scarcely necessary to remark, far from being universally 

 admitted. The methods of investigation heretofore pursued have been of a 

 direct nature, or have consisted in the estimation of the respective amounts of 

 caloric evolved by equal weights, or equal volumes of the different gases in cool- 

 ing through the same range of temperature — the results in the latter case being 

 divided by the specific gravities, in order to pass to the relative capacities of equal 



*■ VOL. XVIII, ■ B 



