known to do to-day, would instead blow the surface
waters away from the easterly side of the ice-formed isthmus, which
would cause a low sea level along its Atlantic side, and this low sea
level would attract the tropical waters from their high level against
Brazil well into the southern seas, and so wash the antarctic
continent to the eastward of the South Shetlands.

The tropical waters thus attracted southward would be cooler than the
tropical waters of to-day, owing to the great extension of cold in the
southern latitudes. Still they would begin the slow process of raising
the temperature of the Southern Ocean, and would in time melt the ice
in all southern lands. Not only the Brazil currents would penetrate
the southern seas, as we have shown, but also the waters from the high
level of the tropical Indian Ocean which now pass down the Mozambique
Channel would reach a much higher latitude than now.

The ice-made isthmus uniting South America to the antarctic continent
would on account of its location be the last body of ice to melt from
the southern hemisphere, it being situated to windward of the tropical
currents and also in a region where the fall of snow is great; yet it
would eventually melt away, and the independent circulation of the
Southern Ocean again be established. But it would require a long time
for ice sheets to again form on southern lands, because of the lack of
icebergs to cool the southern waters. Still, their temperature would
gradually lower with the exclusion of the tropical waters, and
consequently ice would slowly gather on the antarctic lands.

The above theory thus briefly presented to account for the climatic
changes of the high southern latitudes is in full accord with the
simple workings of nature as carried on to-day; and it is probable
that the formation of continents and oceans, as well as the earth's
motions in its path around the sun, have met with little change since
the cold era iced the lands of the high latitudes.

At an early age, previous to the appearance of frigid periods, the
ocean waters of the high latitudes probably did not possess an
independent circulation sufficient to lower the temperature so that
glaciers could form. This may have been owing to the shallow sea
bottom south of Cape Horn having been above the surface of the water,
the channel having since been formed by a comparatively small change
in the ocean's level. For, while considering this subject, it is w