This book is copyright in all countries which
are signatories in the Berne Convention
First Edition 1948
Second Edition 1950
Reprinted (with corrections) 1953
Third Edition 1956
Fourth Edition 1960
MACMILLAN AND COMPANY LIMITED
London Bombay Calcutta Madras Melbourne
THE MACMILLAN COMPANY OF CANADA LIMITED
Toronto
ST MARTIN'S PRESS INC
New York
PRINTED IN GREAT BRITAIN
