AND OTHER WATER WAVES 113 



the wind was therefore 6 s.m.p.h. swifter than 

 the waves at their swiftest. 



In the Mediterranean and other semi -enclosed 

 seas, even where the water is deep, the length 

 and speed of the waves are much less. Conse- 

 quently the effective velocity of the wind, which 

 maintains the eddy on the lee of the travelling 

 ridges, is much greater. 



In all the above cases, which are typical, the 

 velocity of the storm -wave is a few miles per hour 

 less than the velocity of the wind as averaged 

 over a period of from 4 to 100 hours. 



The period of the swells which break upon our 

 shores after storms shows that they travel when 

 in deep water at much greater speeds than do the 

 highest waves of storms. Thus the calculated 

 speed of the unbroken series of 139 waves which 

 I observed at Branksome Chine on December 29, 



1898, was 66.5 statute miles per hour, and that 

 of twelve successive waves observed on February i, 



1899, was ?8 -5 statute miles per hour. Other 

 observations recorded at the same locality, of which 

 particulars have already been given, show that 

 velocities of between 68 and 78 statute miles per 

 hour are normal, though not frequent, for break- 

 ing swells coming to our shores from the west after 

 storms in the Atlantic. 



