AND OTHER WATER WAVES 29 



S. by W. from the upper. When the wind blew up 

 the lake with the force of half a gale I found that 

 the waves near the upper end succeeded each other 

 at intervals of 2 seconds, corresponding to a wave- 

 length in deep water of 20 feet. At a later date 

 Mr. Hamil, a seaman of experience, and captain 

 of the steam gondola which plies on the lake, sent 

 me the following observations which he made upon 

 the larger waves produced in a whole gale of wind. 

 On September 3, 1902, at 8 a.m., there was a 

 light wind blowing up the lake, i.e., from the soutji. 

 At 10 a.m. it rose to a gale, the wind shifting to a 

 little W. of S. Mr. Hamil timed the waves at 

 Yew dale Beck, near the upper end of the lake, 

 with the following results : 



Waves passing point of observation. Waves breaking 



on beach. 

 10.30 a.m. ... 27 per minute 



10.32 a.m. ... ... 24 per minute 



u.oa.m. ... 23 



n.2a.m. ... ... 22 



11.30 a.m. ... 21 



11.32 a.m. ... ... 20 



12.0 a.m. ... 21 



12.2 a.m. ... 20 



Thus the period appeared to be constant after 

 1 1.30 a.m. i.e., an hour and a half after the gale 

 commenced. The length of wave in deep water 

 corresponding to the observed period of 3 seconds 



