275 



PROCEEDINGS 



OF THE 



ROYAL SOCIETY OF EDINBURGH. 



VOL. II. 1850. No. 37. 



Monday, Ath February 1850. 

 The Hon. Lord MURRAY in the Chair. 



The following Communications were read : — 



1. Abstract of a Paper on the Hypothesis of Molecular Vor- 

 tices, and its Application to the Mechanical Theory of 

 Heat. By William John Macquorn Rankine, Civil 

 Engineer, F.R.S.E., F.R.S.S.A., &c. 



The object of this paper is to shew how the laws of the phenomena 

 of Elasticity and Expansion, as connected with heat, may be re- 

 duced to mechanical principles by means of an hypothesis called that 

 of Molecular Vortices. 



The author ascribes the first distinct statement of an hypothesis 

 of this kind to Sir Humphrey Davy, and refers to Mr Joule as hav- 

 ing supported it ; but he states that its consequences, to the best of 

 his knowledge, have not hitherto been developed by means of the 

 principles of Analytical Mechanics. 



The author has endeavoured to do this) so far as the present state 

 of experimental knowledge enables him, introducing such modifica- 

 tions into the hypothesis as are necessary in order to connect it with 

 the undulatory theory of radiation. His researches were commenced 

 in 1842, but were laid aside for nearly seven years from the want 

 of experimental data, which, however, have at length been to a great 

 extent supplied, so far as gaseous bodies are concerned, by the ex- 



VOL. H. 2 B 



