AND OTHER WATER WAVES 133 



each one of uniform height, with a lateral extension 

 many times greater than the distance from crest to 

 crest. 



In 1907 I made the following observations on 

 the want of regularity of waves created by the Trade 

 winds. On January 8th, en route from Colon to 

 Kingston, Jamaica, in a strong NE. Trade wind, 

 I estimated the height of the principal waves at 

 15 feet. Their apparent length was about 200 

 feet. I noted at the time that this strong breeze 

 had continued, to my knowledge, for eight days, 

 and that for some days past there had been no 

 increase either in the size of the waves or in their 

 regularity, indicating, therefore, not only that the 

 maximum size is soon attained (as M. Bertin l has 

 pointed out), but also that there is no continuous 

 approximation towards regularity. The captain of 

 the vessel (S.S. Jamaican) stated that on such a 

 day as this the wind would not vary more than 

 one point of the compass in the course of a four- 

 hour watch, and this is reckoned a very steady 

 wind. But one point of the compass is 1 1 J degrees 

 of arc, which is a very appreciable angle. If one 

 watches the arrow of a sensitive weathercock in a 

 strong breeze, in our own country, it will be seen 



1 Memoir on the " Experimental Study of Waves," Inst. of 

 Naval Architects, 1873. 



