t-15sec 



t-18sec 



.t- 21 sec 



Fig, 9. Profiles of wave patterris, showing the variations 

 of dominant waves with space and time at a wind 

 velocity of 19 in/sec. 



X = 1000 m with the crests a-,, ^21 b,. After a time interval of 



12 seconds the height of the wave b, has decreased while the small 



elevation in the trough of the "double-wave" between points B and 



C has grown up to C2» forming a long stretched crest. During the 



same time another wave ap? grows up at the rear edge of the "group." 



33 



