CLIMATE

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CLIMATE. The ancients denoted by this name the spaces between the imaginary circles* parallel to the equator, drawn in such a maimer over the surface of the earth, that the longest day in each circle is half an hour longer than in the precede ing. According to this division, there were twentyfour climates from the equator, where the longest day is 12 hours, to the polar circle, where it is 24 hours. From the polar circle, the longest day hir creases so rapidly, that, only one degree nearer the pole, it is a month long. The frigid zones, so called, that is, the regions extending from the northern and southern polar circles to the corresponding poles, some geographers have divided again into six climates. We have learned from a more accurate acquaintance with different countries, that heat or cold depends not merely on geographical latitude, but that local causes also produce great variations from the general rule, by which a region lying near the equator should always be warmer than one remote from it. By the word climate, therefore, we understand the character of the weather peculiar to every countiy, as respects heat and cold, humidity and dryness, fertility, and the alternation of the seasons. The nature of a climate is different according to the different causes which affect it, and the observations hitherto made have led, as yet, to no definite result. In general, however, geographical latitude is the principal circumstance to be taken into view in considering the climate of a countiy. The highest degree of heat is found under the equator, and the lowest, or the greatest degree of cold, under the poles. The temperature of the intermediate regions is various, according to their position and local circumstances. Under the line, the heat is not uniform. In the sandy deserts of Africa, particularly on the western coast, also in Arabia and India, it is excessive. In: the mountainous regions of South America, on the contrary, it is very moderate. The greatest heat in Africa is estimated at 70° of Reaumur, or 189£° of Fahrenheit. The greatest degree of cold at the poles cannot be determined, because no one has ever penetrated to them. The greatest altitude of the sun at noon, and the time of its continuance above the horizon, depends altogether on the latitude. Without regard to local circumstances, a country is warmer in proportion as the sun's altitude is greater and the day longer, Xhe elevation of any region above the surface of the sea has likewise an important influence on the CLIMATE. But the nature of the surface is not to be disregarded. The heat increases as the soil becomes cultivated. Thus, for the last thousand years, Germany has been growing gradually warmer by the destruction of forests, the draining of lakes, and the drying up of bogs and marshes. A similar consequence of cultivation seems to be apparent in the cultivated parts of North America, particularly in the Atlantic states. The mass of minerals, which composes the highest layer of a country, has, without doubt, an influence on its temperature. Barren sands admit of a much more intense heat than loam. Meadow lands are not so warm in summer as the bare ground.* The winds, to which a country is most exposed by its situation, have a great influence on the climate. If north and east winds blow frequently in any region, it will be colder, the latitude being the same, than another, which is often swept by milder breezes from the south and west. The influence of the wind on the temperature of a country is very apparent in regions on the seacoast. The difference in the extremes of temperature is least within the tropics. The heat, which would be intolerable when the sun is in the zenith, is mitigated by the rainy season, which then commences. When the sun returns to the opposite half of the torrid zone, so that its rays become less vertical, the weather is delightful. Lima and Quito, in Peru, have the finest climate of any part of the earth. The variations in temperature are greater in the temperate zones, and increase as you approach the polar circles. The heat of the higher latitudes, especially about 59° and 60°, amounts, in July, to 75° or 80° of Fahrenheit, and is greater than that of countries 10° nearer the equator. In Greenland, the heat in* The cultivation of a new country is often attended by most disastrous consequences, which ought not, always, to be imputed to the improvidence of colonists. The new soil, the moment that it is broken up by the plough, and penetrated by the rays of the sun, must necessarily undergo a strong evaporation, and its exhalations, which are not always of a harmless kind, little elevated in the air, are condensed by the cold, which still continues to be sharp, particularly during the night. Hence arise those epidemic maladies which ravage colonies newly established. The destruction of forests, when carried too far, is followed by pernicious effects. In the Cape de Verd islands, it is the burning of the forests which has dried up the springs, and rendered the atmosphere sultry. Persia, Italy, Greece, and many other countries, have thus been deprived of their delightful climates. smnirier is sp great that it melts the pitch on the, vessels. At Tornea, in Lapland, where the sun's rays fall as obliquely, at the summer solstice, as they do in Germany at the equinox, the heat is sometimes equal to that of the torrid zone, because the sun is almost always above the horizon. Under the poles, the climate is, perhaps, the most uniform. A greater degree of cold than any we are accustomed to, seems to reign there perpetually. Even in midsummer, when the sun does not go down for a long time (at.the poles not for six months), the ice never thaws. The immense masses of it, which surround the poles, feel no sensible effect from the oblique and feeble beams of the sun, and seem to increase in magnitude every year. This is very remarkable ;o: for there is the most undoubted evidence that these now deserted countries were, in former ages, inhabited. But, within a few years, large portions of this, continent (if we may so call it) of ice have separated, and floated down to southern seas. This led the English government to adopt the project of penetrating to the north pole. Captains Ross and Parry, one after the other, have sailed as far as possible into the arctic ocean. (See North Polar Expeditions.) From the general division of America into lofty mountainous plateaus and very low plains, there results a contrast between two climates, which, although of an extremely different nature, are in almost immediate proximity. Peru, the valley of Quito, and the city of Mexico, though situated between the tropics, owe to their elevation the general temperature of spring. They behold the paramos, or mountain ridges, covered with snow, which continues upon some of the summits almost the whole year, while, at the distance of a few leagues, an intense and often sickly degree of heat suffocates the inhabitants of the ports of Vera Cruz and of Guayaquil. These two climates produce each a different system of vegetation. The flora of the torrid zone forms a border to the fields and groves of Europe. Such a remarkable proximity as this cannot fail of frequently occasioning sudden changes, by the disr placement of these two masses of air, so differently constituteda general inconvenience, experienced over the whole of America. Every where, however, this continent is subject to a lower degree of heat than the same latitudes in the eastern portion of the earth. Its elevation alone explains this fact, as far as regards the mountainous region; but why,it may be asked, is the same thing true of the low tracts of the country ? To this the great observer, Alexander Humboldt, in his Tableaux de la Nature, makes the following reply: " The comparative narrowness of this continent; its' elongation towards the icy poles; the ocean, whose unbroken surface is swept by the trade winds; the currents of extremely cold water which flow from the straits of Magellan to Peru.; the numerous chains of mountains, abounding in the sources of rivers, and whose summits, covered wit\ snow, rise far above the region of the clouds; the great number of immense rivers, that, after innumerable curves, always tend to the most distant shores ; deserts, ;but not of sand, and consequently less susceptible of being impregnated with heat; impenetrable forests, that spread over the plains of the equator, abounding in rivers, and which, in those parts of the country that are the farthest distant from mountains and from the ocean, give rise to enormous masses of water, which are either attracted by them, or are formed during the act of vegetation,all these causes produce, in the lower parts of America, a climate which, from its coolness and humidity, is singularly contrasted with that of Africa. To these causes alone must we ascribe that abundant vegetation, so vigorous and so rich in juices, and that thick and umbrageous foliage, which constitute the characteristic features of the new continent." To these remarks MalteBrun adds ¦(Universal Geography, vol. v, bodk lxxv): w Assuming this explanation as sufficient for South America and Mexico, we shall add, with regard to North America, that it scarcely extends any distance into the torrid zone, but, on the contrary, stretches, in all probability, very far into the frigid zone; and, unless the revived hope of a northwest passage be confirmed, may, perhaps, reach and surround the pole itself. Accordingly, the column of frozen air attached to this continent is no where counterbalanced by a column of equatorial air. From this results an extension of the polar climate to the very confines of the tropics; and hence winter and summer struggle for the ascendency, and the seasons change with astonishing rapidity. From all this, however, New Albion and New California are happily exempt; for, being placed beyond the reach of freezing winds, they enjoy a temperature analogous to their latitude." (For further information, see MalteBrun's Universal Geography, bookxvii, and the article Wind. Respecting the climate of the U. States, see Darby's View of the U. States, chap, x, Philad. 1828.) ;