Page:Africa by Élisée Reclus, Volume 3.djvu/34

 of the equatorial current, which flow from the Old towards the New World, so that a vessel sailing either east or west parallel with the equator may take advantage either of the main or the counter current to accelerate its speed. The Guinea Stream shifts with the seasons, in September occupying more than half the breadth of the Atlantic to the south of the Cape Verd Islands.

The cause of this movement from west to east in the same direction as that of the globe itself, is a question that cannot be discussed apart or independently of the still unsolved general problem of the circulation of the oceanic waters. The part played in these movements by the rotation of the globe, by the winds, the varying temperature from the surface downwards, the varying degrees of salinity

in the intermingling waters, cannot yet be determined. Certainly none of the different theories suffice to explain all the phenomena observed by the few meteorologists who have themselves visited these oceanic regions. In general the Guinea Stream is regarded as a lateral backwater, a "compensating current" produced by the reflux of the equatorial waters. It cannot in any case be attributed to the direct action of the winds, for it flows in the opposite direction to the trade winds and monsoons prevailing in these waters. Even off the Niger delta and the Cameroons, where the Guinea Stream trends south-eastwards and then southwards till it merges in the equatorial current, the movement is still opposite to the normal direction of the winds. To this phenomenon of the Guinea Stream running counter to the winds and laterally pressed upon by another marine