PHILOSOPHICAL 



TRANSACTIONS 



OF THE 



ROYAL SOCIETY OF LONDON. 



SERIES A. 



CONTAINING PAPERS OF A MATHEMATICAL OR PHYSICAL CHARACTER. 



VOL. 211. 



LONDON : 



PRINTED BY HARRISON AND SONS, ST. MARTIN'S LANE, W.C., 



Jrhitfrs in rbinatg to fis 



MARCH, 1912 



