In height anfl length, and from time to time a wave comes that Is 

 considerably higher than the common run, or Its time Interval from 

 the preceding crest to the following crest observed at a fixed local- 

 ity Is much longer than the time Intervals of the waves before and 

 after this particular wave. These longer or higher waves disappear 

 on their track after some undulations, changing their pattern con- 

 tinuously. If It were possible to observe these conspicuous waves 

 long enough from a high point It would seem that they are replaced 

 by others not so conspicuous, while waves with uncommon heights and 

 lengths are growing up at another place. Thus waves with a height 

 of 3.0 to 3.5 m were observed on the "Heldberg" when the usual 

 height was about 1.5 to 2,5 m (wind velocity 5-6 Beaufort). During 

 the storm In the eastern North Atlantic on 27 Janiiary, 1951, at 

 20 m/sec wind velocity from time to time the wave height attained 

 12-13 m while the average of the common run was about 9 m. On 13 

 January, 1951 > at noon, still larger variations occurred at 14-15 m/sec 

 wind velocity. On the average, the common run was about 4 m In 

 height, while some Individual waves attained a height of 7 m or 

 more. In the evening of this day, the wind increased to about 8 

 Bft. with squalls to 10 Bft. and the wave height of single waves arose 

 to 10-11 m while the average was about 8 m (see Fig. 6). 

 The curve In figure 6 represents the relation 



H = 0.215 ^ tV^-^^^sI V (4a) 



with T s T, . Formula (4a) Is given by the empirical relationship 



H « 0.2l5A.-e'^-^^^P 



23 



