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 latitude, is perhaps as temperate and tolerable as any part of the globe; since we, in ranging it along, did not once meet with such warm weather as is frequently felt in a summer day in England, which was still the more remarkable, as there never fell any rain to refresh and cool the air.

The causes of this lower temperature in the South Sea are not difficult to be assigned, and shall be mentioned hereafter.  I am now only solicitous to establish the truth of this assertion, that the latitude of a place alone is no rule by which to judge of the degree of heat and cold which obtains there.  Perhaps this position might be more briefly confirmed by observing that on the tops of the Andes, though under the equator, the snow never melts the whole year round; a criterion of cold stronger than is known to take place in many parts far within the polar circle.