Proceedings at the Meetings 215 



The following Communications were made to the Society : 



1. The Mass Spectra of the Chemical Elements. By F. W. Aston, 

 M.A., Trinity College. 



2. An examination of Searle's method for determining the viscosity 

 of very viscous liquids. By Kurt Molin. (Communicated by Dr 

 G. F. C. Searle.) 



3. Note on the Diophantine equation t^ ^ x^ -\- y^ + z^ = 0. By 

 H. W. EiCHMOND, M.A., King's College. 



4. Mathematical notes: (1) On the stability of rotating liquid ellip- 

 soids; (2) on the general theory of the stability of rotating masses of 

 liquid; (3) on the stability of periodic motions in general dynamics; 

 (4) on the invariance of the equations of electrodynamics in the Maxwell 

 and in the Einstein forms ; (5) on a j^roperty of focal conies and of bi- 

 circular quartics; (6) on the Hart circle of a spherical triangle; (7) on 

 a proof of the theorem of a double six of lines by projection from 

 four dimensions; (8) on a set of transformations of rectangular axes; 

 (9) on transformations with an absolute quadric; (10) on the reduction 

 of homographv to movement in three dimensions. By Professor 

 H. F. Baker. ^ 



February 23, 1920. 



In the Botany School. 



Mr C. T. R. Wilson, President, in the Chair. 



The following were elected Fellows of the Society : 



E. Cunningham, M.A., St John's College. 



M. C. Vyvyan, B.A., Gonville and Caius College. 



The following Communication was made : 



The Origin of the Vegetation of the Land. By Professor Seward. 



Mr Lister exhibited and described a large collection of butterflies. 



Many exhibits of botanical interest were shewn. 



March 8, 1920. 



In the Cavendish Laboratory, 



Mr C. T. R. Wilson, President, in the Chair. 



The following was elected a Fellow of the Society: 



Terry Thomas, M.A., St John's College. 



The following Communications were made to the Society: 



1. Further notes on the food plants of the Common Earwig {Forficula 

 auricularia). By H. H. Brindley, M.A., St John's College. 



