PllOCEEDINGS. 



Seven hundred and thirty- second Meeting. 



May 25, 1880. — Annual Meeting. 



The Vice-President in the chair. 



The Treasurer and Librarian presented their annual reports. 

 Professor Lovering presented the following report from the 

 Rumford Committee : — 



" The mechanical theory of heat, which treats of heat as heing, not 

 a peculiar kind of matter called caloric, but as being some form or 

 forms of molecular motion, has made necessary and possible a new 

 branch of mechanics, under the name of thermo-dynamics. This 

 theory has not only introduced new ideas into science, but has de- 

 manded the application, if not the invention, of special mathematical 

 equations. Clausius has devoted thirty years to the development of 

 thermo-dynamics, and at the end of his ninth memoir he expresses, in 

 two brief sentences, the fundamental laws of the universe which corre- 

 spond to the two fundamental theorems of the mechanical theory of 

 heat: 1. The energy of the universe is constant; 2. The entropy of 

 the universe tends towards a maximum. 



" Professor J. Willard Gibbs, in his discussion of the ' Equilibrium 

 of Heterogeneous Substances,' derives his criteria of equilibrium and 

 stability from these two theorems of Clausius, and places the two gen- 

 eralizations of Clausius in regard to energy and entropy at the head 

 of his first publication. Having derived from his criteria some lead- 

 ing equations, and having defined his sense of 'homogeneous' and its 

 opposite, he applies these equations : — 



" 1. To the internal stability of homogeneous fluids. 



" 2. To heterogeneous masses, under the influence of gravity or 



