CHAPTER I. 



ON THE NATURAL COURSE OF AN INVESTIGATION OF 

 THE CAUSES OF THE MOVEMENTS OF THE OCEAN. 



Besides the waves, which rise wherever the surface 

 of the water is ruffled by the wind, two apparently 

 distinct kinds of movement are observable in the 

 ocean : the one a streaming onwards of parts of the 

 ocean through itself, which is taking place more or 

 less in all parts of it, and forms the ocean currents ; 

 the other, a movement by which its level is con- 

 stantly changing — rising in one part as it falls in 

 another. This latter forms the tides, and is an 

 alternate piling up and subsiding of the water, and 

 not a current except where the coast line offers such 

 obstruction as to cause a rush of water. 



The first impulse of practical inquirers regarding 

 the causes of ocean currents seems to have been to 

 attribute them to the winds, as ocular demonstration 

 of their action is evident to anyone who watches the 

 ocean waves which are rolled along by every breeze. 

 This apparent action of the winds, together with the 

 general accordance of many of the broad features of 



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