ANALYSIS OF A WAVE. 441 



apparently free and fetterless billows, which 

 have supplied poets with the most beautiful 

 similes of liberty and unrestrained action, can 

 move but in obedience to certain laws which 

 control and direct them. To us nothing in 

 nature appears so unshackled; in. reality not a 

 wave heaves but is under the influence of laws 

 which prescribe its movement, velocity, and 

 form. Is it not so in life ? The movements of 

 an hour, the fresh-rising events which appear 

 to us the most fortuitous things in the world 

 these all have their time, their form, and pres- 

 sure, and place appointed, in the hands of Him 

 in whom we live, and move, and have our being. 

 The following parts are recognised in a wave : 



Its highest part is called the crest, w in the dia- 

 gram. From w to a, is called the front ; from 

 w to w, the back ; from w to h, the height ; and 

 from w to , the amplitude ; a is called the 

 origin, and w the end of the wave. The arrow 

 x x shows the direction of the movement of the 

 wave. 



Wave-like movements in the waters of the 

 ocean arise from two causes the attraction 



