FOREWORD 
This book represents a compilation of the lectures presented at the Institute 
on Underwater Acoustics held at the Department of Physics of The Imperial 
College of Science and Technology of The University of London between July 31 
and August 11, 1961. The institute was conducted by the Continuing Education 
Services of The Pennsylvania State University under a grant from the Scientific 
Affairs Division of the North Atlantic Treaty Organization. 
At the institute, eighteen papers were presented by seventeen outstanding 
scientists in the field of Underwater Acoustics. In addition, eighty-five scientists, 
representing eleven nations, attended the institute and participated in the dis- 
cussions following the presentation of each paper. Since each of the lecturers 
is an authority in his field, these proceedings, which include the bibliographies 
supplied by the lecturers, should provide a valuable source of information for 
workers in the field of Underwater Acoustics. The discussions following the 
lectures, where available, have been included to make these proceedings more 
meaningful to the reader. 
Dr. R. W. B. Stephens of The Imperial College, Co-Chairman of the institute, 
assisted in the preparation of the program and made all arrangements for the 
lecturers and participants. The contribution of Dr. Stephens in the formulation 
of the program and in arranging for the housing of both the lecturers and the 
participants was an important factor in the success of the institute. 
I wish to thank all of the speakers for their efforts in preparing the lectures 
as well as for preparing manuscripts in a form suitable for publication. I am 
grateful to the staff of the Department of Physics of The Imperial College and 
to the staff of Continuing Education Services at The Pennsylvania State Uni- 
versity for their assistance in carrying out the program. I am also indebted to 
Dr. Merritt A. Williamson, Dean of the College of Engineering and Architecture, 
and Dr. John C. Johnson, Director of the Ordnance Research Laboratory, at The 
Pennsylvania State University for their support and interest. 
Vernon M. Albers 
Chairman 
