During our voyage along this coast, we generally observed that a
current set us to the northward, at the rate of ten or twelve miles
every day. When in about the latitude of 8 deg. S. we began to be attended
by vast numbers of flying fish and bonitos, which were the first we
had seen after leaving the coast of Brazil. It is remarkable that
these fish extend to a much higher latitude on the east side of
America than on the west, as we did not lose them on the coast of
Brazil till near the southern tropic. The reason, doubtless, of this
diversity, is owing to the different degrees of heat obtaining on
different sides of the continent in the same latitude; and, on this
occasion, I use the freedom to make a short digression on the heat and
cold of different climates, and on the variations which occur in the
same places at different times of the year, and in different places in
the same degree of latitude.

The ancients conceived that of the five zones into which they divided
the surface of the globe, two only were habitable; supposing that the
heat between the tropics, and the cold within the polar circles, were
too intense to be supported by mankind. The falsehood of this idea has
been long established; but the particular comparison of the heat
and cold of these various climates have as yet been very imperfectly
considered. Enough is known, however, safely to determine this
position, that all the places within the tropics are far from being
the hottest on the globe, as many within the polar circle are far from
enduring that extreme degree of cold to which their situation seems to
subject them; that is to say, that the temperature of a place depends
much more upon other circumstances, than upon its distance from the
pole, or its proximity to the equinoctial line.

This proposition relates to the general temperature of places taking
the whole year round, and, in this sense, it cannot be denied that
the city of London, for instance, enjoys much warmer seasons than
the bottom of Hudson's Bay, which is nearly in the same latitude, but
where the severity of the winter is so great as scarcely to permit
the hardiest of our garden plants to live. If the comparison be made
between the coast of Brazil and the western shore of South America,
as, for example, between Bahia and Lima, the difference will be found
still more considerable; for, though the coast of Brazil is extremely
sultry, yet the coast of the South Sea, in the same la