AND OTHER WATER WAVES 27 



extent upon the strength of the wind, but even in 

 a whole gale (October 6, 1901) the little breakers 

 on the shelving lee shore followed one another at 

 intervals of only i second. 1 The wave-length was 

 not measured, but appeared to be about 3 feet. 

 The whole of this effect was soon produced, being 

 a matter of minutes ; the height of the waves 

 quickly diminished when the wind lulled, and could 

 be seen to increase instantaneously when squalls 

 occurred, the height increasing by a considerable 

 fraction during a squall lasting four minutes. 



If we take the greatest length of waves observed 

 in the Round Pond on the day referred to as 3 feet, 

 and adopt the simple mean of the shortest ( i inch) 

 and the longest (36 inch) wave as the average 

 wave-length for the pond during a gale, we find 

 that there is then a series of 436 consecutive waves, 

 of which the longest is 1-2 2 3rd of the length of the 

 series, or of the length of fetch of the wind, or of 

 the length of run of the waves. 



On the Serpentine Water in Hyde Park, a much 

 larger pond, the shape of which, however, is not 

 favourable to the development of waves, I measured 

 those produced in a strong SW. breeze, going out 



1 The calculated length of a i -second wave in deep water is 

 5 feet. The velocity of the wind in London was 50 statute 

 miles per hour. 



