147 
Ordinary Meeting, March 21st, 1871. 
E. W. Binney, F.R.S., F.G.S., President, in the Chair. 
Mr. John Hopkinson, D.Sc., was elected an Ordinary 
Member of the Society. 
“ On the Mechanical Equivalence of Heat,” by the Rev. 
H. Highton, M.A. 
The following is an abstract of the arguments as given in 
the paper and brought out in the subsequent discussion. 
1. The author apologised for having mentioned other 
names in connection with great discoveries which were 
undoubtedly due primarily to Dr. J oule, and spoke of the 
very great value of Dr. J oule’s experiments, even when he 
did not agree with the deductions drawn from them. 
2. The subject is of extreme importance both for the 
interpretation of physical phenomena and for determining 
what limits are assigned by the stern laws of Nature to the 
exercise of man’s mechanical and scientific skill. 
3. No doubt Dr. Joule has ascertained the heat ordinarily 
derived from the destruction of energy, by means of friction 
with various substances ; but it has been assumed, in defi- 
ance of facts, that the numerical relations which connect 
heat and energy in the case of friction hold good when 
energy and heat produce or destroy each other by any 
other means. 
4. In the case of friction itself, energy is not transformed 
simply into heat, but partly into heat and partly into an- 
other kind of energy, which is involved in the expansion of 
the solids or liquids acted on. 
Pbocis^dxk(»s — Lit. <fe Phil. Soc. — Yol. X. — No. 13. — Session 1870-71. 
