PERGAMON PRESS INC. 



122 East 55th Street, New York 22, N. Y. 



1404 New York Avenue N.W., 



Washington 5, D.C. 



PERGAMON PRESS LTD. 



Headington Hill Hall, Oxford 

 4 & 5 Fitzroy Square, London W.l. 



PERGAMON PRESS S.A.R.L. 

 24 Rue des Ecoles, Paris V^ 



PERGAMON PRESS G.m.b.H. 

 Kaiserstrasse 75, Frankfurt am Main 



Copyright 



© 



1961 



Pergamon Press Ltd 



Library of Congress Card Number 61-14246 



Set in Imprint 11 on 12 point and printed in Great Britain at 

 THE ALDEN PRESS. OXFORD 



