478 
CURRENTS AND WHALING. 
as we neared the coast, by the equatorial stream that sets down the 
Mozambique Channel. This stream is usually confined to narrow 
limits, but at some seasons becomes strong enough to throw its waters 
in a southwest direction beyond the Aguillas Bank. There is little 
doubt that this equatorial stream is superficial, overlying the Southern 
Polar Stream, a portion of which latter, touching the Aguillas Bank, 
is forced up by that obstruction to the surface. This is evident by its 
reducing the temperature of the waters on soundings at the Cape 
to 62°. This Polar Stream is divided by the Cape: the eastern part 
sets along the east coast of Africa as a submarine stream, and on 
reaching the island of Madagascar is found to flow north, along its 
west shores. The other and larger portion is deflected, and flows to 
the northward, along the west coast, and finally forms the Great Equa¬ 
torial Stream of the South Atlantic. 
We have seen that a great equatorial stream, flowing westward, is 
found both in the Atlantic and Pacific. One also, according to Hors- 
burgh, exists in the Indian Ocean, in the latitude of 3° N., which may 
be traced to that polar stream which we have seen to flow along the 
western coast of New Holland, and which must of necessity sweep the 
coast of Java and Sumatra. This stream has in the Indian Ocean 
been observed to flow at the rate of fifty-six miles in twenty-four hours. 
Upon the same authority, it appears that on the Malabar coast a 
current sets constantly to the southward. 
About the Chagos Archipelago, the currents are periodic, setting 
west and northwest during the prevalence of the southeast monsoon, 
and southeast in the months of December and January, when the wind 
blows from the northwest. About the Comorro Islands, on the con¬ 
trary, the prevailing current is from the westward; and off the north 
end of Madagascar, likewise, a westerly current prevails throughout 
the year. On this account the ports of that island are difficult to make, 
and ought to be approached from the windward, as it would be difficult 
to beat up to them against the current. 
In the Mozambique Channel, a current sets northward, along the 
western shore of Madagascar; while on the coast of Africa opposite, 
the water sets almost continually to the south. But on the same coast 
to the north of the line, a weak current is found setting towards the 
Persian Gulf, and thus causing the current we have stated to run 
southwards on the Malabar coast. 
The Equatorial Stream of the South Atlantic may be cited as fur¬ 
nishing a good instance of the effect that currents may produce on 
climate. It always includes the island of Anno Bon within its influ¬ 
ence, while St. Thomas, in longitude 6J° E., and immediately under 
