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 woul(3, 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 
