appreciation for the cooperation and help provided by Mr. 
Knauss, Mr. Gordon Lil, and Mr. Rowe. 
At the Beach Erosion Board, the entire organization has 
followed the progress of this paper with great interest. The 
help and cooperation of Colonel Gessler, Dr. Martin A. Mason, 
ir. R. O. Eaton, Mr. Joseph Caldwell, Mr. Jay V. Hall, and Mr. 
Thorndyke Saville, Jr. are deeply appreciated. 
At Woods Hole Oceanographic Institution, Admiral E. H. Smith 
has helped by providing the staff for the auto-correlation analy- 
sis of a wave record. Mrs. Mary Hunt directed the work involved. 
Theoretical discussions with Columbus Iselin have suggested 
many future refinements. 
At Scripps Institution of Oceanography, I wish to thank 
Professor R. S. Arthur and Professor W. H. Munk for the many 
stimulating conferences on wave forecasting we have had and for 
their continued correspondence on various points of wave theory. 
The set of lecture notes prepared at Scripys is an excellent 
supplemented source on wave theory. 
Professor John W. Tukey of Princeton University is one person 
to whom very special thanks are due. Without his help, suggestions, 
and previous works, this book could never have been written. The 
author was bogged down at the end of Chapter 6 when Professor 
Tukey suggested the mechanism of the filters employed in Chapter 
7 for the more realistic wave systems studied in that chapter. 
The tremendous importance of the methods which he has developed 
- 322 - 
