SNOW-WAVES AND SNOW-RIPPLES 207 



wind exceeded that of the waves an eddy with 

 horizontal axis was maintained on the lee of 

 each, and the ridges were rapidly increased in 

 height. 



Second Case. — During a voyage from Southamp- 

 ton to Colon and back in 1 9 1 2 I carefully observed 

 the sea when the following wind blew obliquely 

 across the swell. I was much struck with the 

 extreme slowness with which new waves grew and 

 the small effect of the wind upon the height of the 

 swell. When the swell and the waves which cross 

 it do not differ much in height there are no wind- 

 eddies with long horizontal axes, but on the con- 

 trary, the eddies are cut up into small lengths 

 and have their axes tilted. In this form they can 

 have little effect in raising waves, and, as far 

 as the circulation of the air is in the horizontal 

 plane, it tends to create whirlpool motion instead 

 of waves. 



•When wind begins to blow upon the plane sur- 

 face of an enclosed sheet of water, its wave-making 

 action is at first slow but afterwards proceeds 

 quickly. The rapidity with which short but angry 

 waves are formed upon lakes is a matter of common 

 report. Whether this is appreciably increased by 

 the amount of disturbance reflected from the shore 

 I do not know, but the rapid growth of waves is, 



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