455 



May 7, 1857. 

 IN BURLINGTON HOUSE. 



The LORD WROTTESLEY, President, in the Chair. 



The following list of Candidates recommended by the Council 

 for election into the Society was read, in accordance with the 

 Statutes : 



Lionel Smith Beale, Esq. 



George Boole, Esq. 



George Bowdler Buckton, Esq. 



Thomas Davidson, Esq. 



George Grote, Esq. 



Rowland Hill, Esq. 



The Rev. Thomas Kirkman. 



John Marshall, Esq. 

 Andrew Smith, M.D. 

 Robert Angus Smith, Esq. 

 Charles Piazzi Smyth, Esq. 

 Henry Clifton Sorby, Esq. 

 John Welsh, Esq. 

 Joseph Whitworth, Esq. 



William Marcet, M.D. 



The following communications were read : 



I. " On the Plasticity of Ice, as manifested in Glaciers." By 

 JAMES THOMSON, A.M., C.E. Belfast. Communicated by 

 Professor W. THOMSON, F.R.S. Received April 1, 1857. 



The object of this communication is to lay before the Royal So- 

 ciety a theory which I have to propose for explaining the plasticity 

 of ice at the freezing point, which is shown by observations by Pro- 

 fessor James Forbes, and which is the principle of his Theory of 

 Glaciers. 



This speculation occurred to me mainly in or about the year 1848. 

 I was led to it from a previous theoretical deduction at which I had 

 arrived, namely, that the freezing point of water, or the melting 

 point of ice, must vary with the pressure to which the water or the 



