OCEAN CURRENTS 153 



per day, with maxima of 40 to 50 miles in certain areas. The 

 Guinea Current is warmer than the Equatorial Current; only 

 in the summer (Augtist) has the westerly portion of the latter a 

 higher température (over 28° C). At this time the Guinea 

 Current is cooler than in other months, probably because the 

 rainfall of the south-west monsoon cools the surface waters. 

 The density of the Guinea Current is less than that of the 

 Equatorial, probably for the same reason, since it lies for the 

 most part in the doldrums, with their calms and heavy rains. 

 The sea off the coast of Upper Guinea is frequently cool, and 

 for days at a time in July, August, and September is only 

 19° C. to 20° C. Farther from the coast and in deeper water 

 the température at the same time is from 255 to 26'5° C, the 

 normal température of the Guinea Current. 



Along the coast between 4° and 7° W. L. — that is, off Cape 

 Three Points — the water température is between 20° and 

 22° C, and similarly for the whole of the Slave Coast farther 

 east. The breezes from the warmer Guinea Current flowing 

 over this cooler water produce numerous fogs, which make 

 this coast dangerous for navigation. Between the Bissagos 

 and Cape Palmas this cold coastal water is not met with. 



Theory of THE Atlantic Equatorial Currents.^ — Thèse 

 currents lie in the région of the trade winds and the doldrums 

 (or ' ' horse latitudes ") . The north-east trade wind is strongest 

 in winter ; in February between Cape Verde and the Guayanas 

 it blows with a strength of 5 to 6 on the Beaufort scale, its 

 direction being in its easterly area north-north-east, in the 

 centre at 40° W. L. about north-east, and off the Lesser 

 Antilles east-north-east. 



The south-east trade is not so strong, being at the most 4 

 on the Beaufort scale. Its direction is between 5° and 10° 

 S. L., west of south-west; eastwards from Ascension more 

 south-south-east ; and eastwards of the Greenwich meridian 

 south ; on the African coast south-south-west to south-west. 



Near to the Equator, and especially near the calm zone, the 

 south-east trade comes more from the south, and in its northern 



