Geology 



and to some extent also navigation, they are the ones 

 usually indicated by the term " ocean currents." Any 

 good atlas will contain a map showing the distribution 

 and direction of these currents, but it is of considerable 

 interest to inquire into their causes, and for this purpose 

 it may be well to study in some detail the currents of 

 one ocean, say, the Atlantic. 



It will be seen from the sketch map Fig. 3 that there is 

 a broad westerly-flowing current in the neighbourhood of 

 the equator. This is really two currents the Northern 



FM. INDIAN OCEAN RED S E.A 



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1000 

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 I60QI 



80* GO* 



70- -* 7O- 





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1200 

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S N 



FIG. 2. Diagram to illustrate the Temperatures of the Indian Ocean and 



the Red Sea. 



Equatorial and the Southern Equatorial separated from 

 one another by a smaller and somewhat variable easterly- 

 flowing current, variously known as the Counter and the 

 Guinea Current. 



For the purpose of investigating the main cause of 

 the currents of the Atlantic, we may consider the 

 Equatorial as one great broad westerly-flowing stream 

 which, when it reaches the South American continent in 

 the neighbourhood of Pernambuco, divides into two, one 

 passing to the north-west along the coast of Brazil, past 



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