CHAPTER I 



Introduction Waves on ponds Waves on lakes Coniston 

 Water Lake of Geneva Lake Superior Waves in semi- 

 enclosed seas Western Mediterranean China Sea. 



Introduction 



MEASUREMENTS of waves at sea by means of the 

 eye are not susceptible of great accuracy ; but the 

 irregularity of the waves themselves is so con- 

 siderable, especially in their most important condi- 

 tion, which is during storms, that it is more useful 

 to measure many waves somewhat roughly than 

 to obtain (even if it be possible) the precise 

 measurement of a few. The advantage of the mere 

 number of observations does not, however, apply 

 when we pass from rough measurements by careful 

 observers to mere guessing at the dimensions of 

 waves as seen from on board ship . Measurements of 

 the height of waves, for instance, taken in the usual 

 way by finding the height above the ship's water- 

 line from which a neighbouring wave-crest just 

 intercepts the horizon, are believed to be accurate 



