a sensible
diminution of temperature near the tropic, for the Brazilian soil would
no longer be heated by the sun; so that the atmosphere would be less
warm, as also the neighboring Atlantic. On the other hand, the whole of
Europe, Northern Asia, and North America, would be chilled by the
enormous quantity of ice and snow, thus generated on the new arctic
continent. If, as we have already seen, there are now some points in the
southern hemisphere where snow is perpetual down to the level of the
sea, in latitudes as low as central England, such might assuredly be the
case throughout a great part of Europe, under the change of
circumstances above supposed: and if at present the extreme range of
drifted icebergs is the Azores, they might easily reach the equator
after the assumed alteration. But to pursue the subject still farther,
let the Himalaya mountains, with the whole of Hindostan, sink down, and
their place be occupied by the Indian Ocean, while an equal extent of
territory and mountains, of the same vast height, rise up between North
Greenland and the Orkney Islands. It seems difficult to exaggerate the
amount to which the climate of the northern hemisphere would then be
cooled.[186]

But the refrigeration brought about at the same time in the southern
hemisphere, would be nearly equal, and the difference of temperature
between the arctic and equatorial latitudes would not be much greater
than at present; for no important disturbance can occur in the climate
of a particular region without its immediately affecting all other
latitudes, however remote. The heat and cold which surround the globe
are in a state of constant and universal flux and reflux. The heated and
rarefied air is always rising and flowing from the equator towards the
poles in the higher regions of the atmosphere; while in the lower, the
colder air is flowing back to restore the equilibrium. That this
circulation is constantly going on in the aerial currents is not
disputed; it is often proved by the opposite course of the clouds at
different heights, and the fact has been farther illustrated in a
striking manner by two recent events. The trade wind continually blows
with great force from the island of Barbadoes to that of St. Vincent;
notwithstanding which, during the eruption of the volcano in the island
of St. Vincent, in 1812, ashes fell in profusion from a great height in
the atmosphere upon Barbadoes.[187] In like manner, during the great
er