PHILOSOPHICAL TRANSACTIONS 
OF THE 
ROYAL SOCIETY OF LONDON. 
Series A, Vol. 222. Pp. 45-56. 
THE PROBLEM OE FINITE FOCAL DEPTH 
REVEALED BY SEISMOMETERS. 
||y - . c- • . .y ■ 
BY 
GEORGE W. WALKER, A.R.C.Sc., M.A., F.R.S., 
FORMERLY FELLOW OF TRINITY COLLEGE, CAMBRIDGE. 
Printed and Published for the ROYAL SOCIETY by 
HARRISON AND SONS, Ltd., 44-47, ST. MARTIN’S LANE, LONDON, W.C. 2. 
Printers in ©rtriuarn ta 5)is jHajestp. 
1921. 
Price One Shilling and Sixpence. 
A 595. 
5.8.31 
