OCEAN CURRENTS 149 



5. Currents in the land-locked Atlantic seas. 

 i. THE EQUATORIAL CURRENTS. There are two main 

 equatorial currents 



(a) The Northern Equatorial Current, corresponding to the 

 north-east trade wind. 



(b) The Southern Equatorial Current, corresponding to 

 the south-cast trade wind. 



The Northern Equatorial Current was first described by 

 Findlay (1853). It is a variable current, since it covers different 

 areas of the ocean at different times of the year. Between 20 

 and 25 W. L. its southern boundary varies from 6 N. L. in 

 March and May to 12 N. L. in September. The current charts 

 for the Atlantic Ocean show a variation of from 5 to 30 sea- 

 miles per day. Under the land on the African coast the drift 

 is weaker, off the West Indian Islands stronger, than the 

 average. The greatest velocity is in the period from December 

 to June, when over 40 sea-miles is recorded. 



The Southern Equatorial Current is met with from the 

 eastward of 30 W. L. and to the south to 15 S. L. as a strong 

 permanent stream. Our current charts show it in February 

 and March as far west as the island of San Thome. In the 

 mqridian of Greenwich the northern edge of this stream is 

 about i or ij N. L. ; in 10 W. L. it is 3 to 4 N. L., and 

 continues in this position to 30 W. L. 



The Equatorial Current divides at Cape San Roque, one 

 part (the Brazil Current) running south along the coast of 

 South America, the other running north-west. This north- 

 westerly branch unites near the Amazon estuary with a branch 

 of the Northern Equatorial Current, and then again with the 

 main Northern Equatorial Current, all three ultimately con- 

 tinuing as the Guayana Current. This north-western diversion 

 of the South Equatorial Current attains a velocity of from 30 

 to 60 sea-miles a day in the vicinity of Cape San Roque. The 

 greatest velocity is ; loojmiles a day, which is attained in the 

 northern summer. 



The velocity of the equatorial currents is both large and 



