CURRENTS OF THE SEA. I43 



level, can not balance each other. It is immaterial, as before 

 stated, whether this difference of specific gravity be caused by 

 temperature, by the matter held in solution, or by any other thing ; 

 the effect iS the same, namely, a current. 



274. That the sea, in all parts, holds in solution the same kind 

 of solid matter ; that its waters in this place, where it never rains, 

 are not salter than the strongest brine ; and that in another place, 

 where the rain is incessant, they are not entirely without salt, 

 may be taken as evidence in proof of a system of currents or of 

 circulation in the sea, by which its waters are shaken up and kept 

 mixed together as though they were in a phial. Moreover, we 

 may lay it down as a law in the system of oceanic circulation, 

 that every current in the sea has its counter current ; in other 

 words, that the currents of the sea are, like the nerves of the hu- 

 man system, arranged in pairs ; for wherever one current is found 

 carrying off water from this or that part of the sea, to the same 

 part must some other current convey an equal volume of water, 

 or else the first would, in the course of time, cease for the want 

 of water to supply it, 



275. Currents of the Atlantic. — The principal currents of 

 the Atlantic have been described in the chapter on the Gulf Stream. 

 Besides this, its eddies and its offsets, are the equatorial current 

 (Plate VI.), and the St. Roque or Brazil Current. Their fountain- 

 head is the same. It is in the warm waters about the equator, 

 between Africa and America. The former, receiving the Amazon 

 and the Oronoco as tributaries by the way, flows into the Carib- 

 bean Sea, and becomes, with the waters (^ 35) in which the 

 vapors of the trade-winds leave their salts, the feeder of the Gulf 

 Stream. The Brazil Current, coming from the same fountain, is 

 supposed to be divided by Cape St. Roque, one branch going to 

 the south under this name (Plate IX.), the other to the westward. 

 This last has been a great bugbear to navigators, principally on 

 account of the difficulties which a few dull vessels falling to lee- 

 ward of St. Roque have found in beating up against it. It was 

 said to have caused the loss of some English transports in the last 

 century, which fell to leeward of the Cape on a voyage to the 

 other hemisphere ; and navigators, accordingly, were advised to 

 shun it as a danger. 



276. This current has been an object of special* investigation 



