.1. 



PROCEEDINGS 



OF THE 



CAMBRIDGE PHILOSOPHICAL 

 SOCIETY 



VOL. XX. PART II. 



[Michaelmas Term 1920.] 



CAMBRIDGE 



AT THE UNIVERSITY PRESS 



AND SOLD BY 

 DEIGHTON, BELL & CO., LIMITED, 

 AND BOWES & BOWES, CAMBBIDGE. 



CAMBRIDGE UNIVERSITY PRESS, 



C. F. CLAY, MANAGER 



FETTER LANE, LONDON, E.G. 4 



1921 



Price Five Shillings Net 



January 1921. 



