While the negro oh the ( oast or a is simic!;c:ii unremitting heat, the inhabitant of Pul u breathes an air equally mild and temperate, and is perpetually sha,k(I under a canopy of may doltds, wftn,i 1111.C1 CCIAS fierce beams (al the sun, without obstructing his friendly influence. Along tile eastern coast of Amu, lea, the climate, though 11101.; to that of the torrid zone in other parts of the earth, is nevertheless considerably milder than in other countries of Asia and Africa wiiich lie in the same latitude. If from the southern tropic we continue our progress to the extremity of the Ame rican continent, we meet with frozen seas, and countries, horrid, barren, and scarcely habitable for cold, much sooner than in the north." Such is the notion universally entertained respecting the climate of America. The New World is believed on the whole to he ten degrees colder by Fahrenheit's scale than the corresponding parallels in the ancient continent. The character of excessive humidity has likewise been ascribed to the American climate. The surface of the ground, covered with a boundless extent of impervious forest, never feels the direct influence of the sun ; while the atmosphere becomes charged with moisture from the perspiration of the multiplied sur faces of the leaves. In confirmation of this principle, it is asserted, that since the first settlement of North Ame rica, the climate, in proportion as cultivation spreads, has grown sensibly milder, drier, and more salubrious. The western continent, still cold and humid from the bosom of the ocean, betrays its recent origin.* Vet the persevering industry of man will in time correct the defects, and subdue the luxuriance of nature ; and, by draining the marshes, and opening the surface of the ground to the genial action of the solar beams, it will not only heighten the productive powers of the soil, but will gradually soften and improve the quality of the atmosphere.
Much indeed can be effected by the labour and inge nuity of man. But the theory now sketched, is, we fear, to be regarded rather as the birth of a lively fancy, thm the offspring of accurate science. We are even disposed to question the exactness of the statements on which it rests. America furnishes no register of the indications of the hygrometer, and with instruments so radically defective, the fed observations of that kind which have been made in Europe, can scarcely be deemed of any value. But from a simple fact noticed by Di' Franklin, we may fairly conclude, that, in Pennsylvania at least, the air is on the whole drier than in the neighbourhood of Loh don, or even of Paris. The American philoso pher remarked, that a small mahogany case, which fitted exactly in England, constantly shrunk, and became loose, after having been carried across the Atlantic ; hut re covered, in a great measure, its original dimensions, when conveyed to France, The cold which prevails in most parts of America through the winter, is, no doubt, most intense ; but, in return, those regions during summer are likewise op pressed by excessive heat. Nor have we any sufficient proof that the climate of the New World, taking the average of the seasons throughout the year, is really colder on the whole than in that of the ancient continent.
It is more consistent with reason to believe, that, though Ann_rica exhibits both extremes of the scale, yet the rigours of winter arc there compensated by the scorch ing heats of summer, and that the mean temperature, !Or a series of years, is the same beyond the Atlantic, as in any other part of the globe hat ins; the same lati tude and elevation. AVe can place very little reliance on the scanty registers of the thermometer kept in America." Nay, from the mode in which such observa tions are usually made, there is an evident tendency to give results considerably below the truth. The degrees of the thermometer are generally noted in the morning and the evening, and about the height of the day. But not long after sun-set, the cold continues with very lit tle increase until day-break ; so that the cold during the night is nearly stated twice in the register, while the greatest heat of the day only appears once ; and conse quently the mean of the three numbers must be really less than w hat would have been obtained from a more equal distribution. The preferable method of ascer taining the mean temperature of any place, is to exa mine the heat of the ground at some considerable depth, and which may be discovered with great precision, by plunging a thermometer in a copious spring, or in wa ter fresh drawn from a deep close well, or, still better, in what flows from a pump which has been worked for a few minutes. Earth and rock are such slow conductors of heat, that, not many feet below the surface, the vicis situdes that mark the revolution of the year are con founded and lost in the uniform temperature which per vades the general mass, and which is the result of those accumulated impressions made during a long succession of ages. The heat of a well at New York, and that of another at Kingston, in the island of Jamaica, which lies in the American Archipelago, have both been carefully observed, and found to agree very nearly with the for mula given by Professor Mayer of Gottingen, for the mean temperature of the corresporlding parallels in Eu rope and Asia. It is indeed alleged, that a draw-well near Philadelphia was several degrees colder ; but the bottom of an open pit must evidently be cooled below the standard, since it will experience the full impres sion of winter without receiving the influence of sum mer, the chilled air, by its superior gravity, constant ly descending, while the warmer air hangs stagnant over the mouth of the shaft. The springs about Hud son's Bay are also, it would appear, unusually cold. These springs, however, are merely superficial, and flow through a bed of frozen earth. But if we pierced through that hard crust, we should, no doubt, meet, at a certain depth, with a milder and unchanging temperature. This limiting depth, which, in Europe, is only about four feet, must be proportionally greater in America, and particu larly towards the more northern parts, where the vicissi tudes of heat and cold me extreniL.