for modern geophysical observations, these "old fashioned" simple 

 "observations by eye" may perhaps appear too primitive today. Most 

 of them were proposed and have already been used in the past century. 

 But a great deal of our empirical knowledge on waves today is based 

 on such direct observations, and up to date these simple observations 

 by eye have proved very useful when taken carefully and utilized 

 critically. There are descriptions of these methods in several 

 textbooks on waves (V. Cornish [4], 0. Kriimnel [5]> H. Thorade [6]) 

 and more recently they are briefly discussed in H. 0. Pub. No. 602 

 by H. B. Bigelow and W. T. Edmondson [7]. 



The time intervals between succeeding crests of waves at a fixed 

 locality* can be estimated from shipboard with a fair degree of ac- 

 curacy by observing the rise and fall of the water, observing for 

 example, foam patches, seaweed or other bodies drifting Just beneath 

 the sea surface. This method was shown to be very useful by V. 

 Cornish. But in taking such measurements, it is necessary to observe 

 a large number of single vertical oscillations under the given con- 

 ditions, because the single values of periods and heights of succeed- 

 ing waves differ over a large range. Furthermore, it should be warned 

 against simply averaging these widely scattered observations. There 

 is much confusion in our empirical knowledge of the relation between 

 wind and waves due to the fact that one has considered only some in- 

 dividual observations under certain conditions, or that one has sub- 

 marized the meastirements by taking "average values" over a large 

 range of variation. 



In the fall of 1950 and the winter of 1950-5l> while crossing 



*This quantity will be referred to hereafter as "wave period." 



10 



