PHILOSOPHICAL TRANSACTIONS 
OF THE 
ROYAL SOCIETY OE LONDON 
Series A, Vol. 218 . TITLE, Ac. 
^ vSH 
' ' . * 
1 V 
TITLE, CONTENTS, INDEX, 
A, YOL. 218. 
Printed and Published for the ROYAL SOCIETY by 
HARRISON AND SONS, 44-47, ST. MARTIN’S LANE, LONDON, W.C. 
Printer £ in ©rttuiarg to Sts iHajestp. 
1919. 
&C. 
A 569. 
Price Sixpence. 
2L7.19 
