PHILOSOPHICAL 



TRANSACTIONS 



OF THE 



ROYAL SOCIETY OF LONDON. 



t* 



SERIES A. 



CONTAINING PAPERS OF A MATHEMATICAL OR PHYSICAL CHARACTER. 



VOL. 213. 



LONDON: 



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



|)rijrtfrs in rbinarg lo $is 



FEBRUARY, 1914. 





