Frigid zone

“ The east wind, which extends to about 25 or 30 degrees on each side the equator, exerts its action round the globe in the torrid zone; the north wind almost always as constantly in the frigid zones. Therefore it may be said that the east wind occupies the torrid zone, the north wind the frigid zones, and with respect to the temperate zone, the winds which reign there are merely currents [102] of air produced by these two winds, whose direction tends to the eastern points. ”

“ However, if we should climb up a high mountain, in either of the Termperate zones or even in the Torrid zone, we would notice that the climate soon becomes colder and colder the farther we go up above the lowlands.
The climate of a country depends chiefly on its being in one or another of these zones.
In the Frigid zones we should see mountains of ice and endless fields of snow.
The people live in huts of snow and ice. They dress in fur and even then can hardly keep warm. ”

“ But I think myself that one feels the cold of the northern frigid zone more than that of the south.”
“Well, sor,” cried Barney, not to be outdone in an argument, “what’s that but being a bit colder!”
“You may be colder,” laughed the professor, “but the weather is not.”
“Shure, thin, phwy is it that I am so much colder?” protested Barney.
“A peculiar state of affairs which gives two different colds. The atmosphere at the South Pole is a trifle more mild. It is a volcanic region, and perhaps that may account for it. It is true that the Arctic cold is more penetrating. ”

“ Once forced from their anchorage, the first storm that arises drifts them to sea, where the beautiful law which renders ice lighter than the warmest water, enables it to float, and drifts southward a vast magazine of cold to cool the tepid water which bears it along—the evaporation at the equator causing a deficit, the melting and accumulation of the ice in the frigid zone giving rise to an excess of accumulation, which tends, along with the action of the air and other causes, to institute and maintain the transporting current. ”

“ Now all the land that lies under the zones between the hot and the cold belts can be occupied; but it is likely that owing to location the lands differ somewhat, so that some are hotter than others; the hottest being those that are nearest the torrid belt. But lands that are cold, like ours, lie nearer the frigid zones, where the frost is able to use its chilling powers. ”

“ But the vast blanket of snow which descends annually upon the colder zones conveys downward the severe chill of higher layers of the air, borrowing from a mighty storehouse of cold which broadly impends above the earth. This snow blanket must be removed, and its stored cold overcome by solar heat, before agriculture can begin, and in this process weeks or months pass away, the effect being greatly to reduce the area of the earth's surface which is suitable for human habitation.
The snow of the frigid zones does not wait for the sun to reach it. It travels toward the tropics to meet the sun. ”

“ During much of the time smoke from forest and prairie fires (in the dry season) , dust (in deserts) , and water-vapour give the sky a pale whitish appearance. In the heart of the trade-wind belts at sea the sky is of a deeper blue. Twilight within the tropics is shorter than in higher latitudes, but the coming on of night is less sudden than is generally assumed.
Climatic Subdivisions.—The rational basis for a classification of the larger climatic provinces of the torrid zone is found in the general wind systems, and in their control over rainfall. ”

“ These currents are strongest where the diurnal range of temperature is greatest and where the local topography is of suitable configuration. Particularly favorable are steeply declining shores, narrow bays and inlets, girded by mountains or lofty hills. During the day heated air ascends such declivities with alacrity, like smoke through an inclined flue, while at night, when cooled by radiation and contact with the soil, it rushes torrentlike down the valleys and hillsides, passing out to sea, often in sudden squalls that embarrass, or endanger, small sailing craft. ”

“ Twice in the twenty-four hours the littoral zone is covered by water and exposed to the direct rays of the sun or the cooling effects of the night. There is a great range of temperature; mechanical agencies produce their maximum effects,” [171] and physical conditions in general are most varied. Still greater diversity is introduced by the fact that the zone is inhabited by both marine and terrestrial organisms, while the evaporation of the sea-water which flows over tidal marshes and lagoons leads to the formation of saline deposits. ”

“ This prevalence of westerly winds beyond the tropics is readily explained by the same reasoning which has been applied to the Trades blowing within them. The swift moving air of the torrid zone, on being rarefied and raised up, flows along towards the poles, and in a direction from the equator, above the cooler and slower-moving air, which, as I have already described, is drawn along the surface of the earth from the temperate regions beyond the tropics. ”

“ Except near the United States the coast lands are tropical or semi-tropical; and the products of the soil, which in many quarters is extraordinarily deep and rich, are those which naturally result from extreme humidity and heat. Next comes an intermediate zone varying in general height from about 2000 to about 4000 feet, where the rainfall, though less abundant than on the coast, is ample, and the climate far more salubrious than below. ”

“ They strike the imagination of the vulgar; as order everywhere astonishes, when we cannot easily ascend to first causes. Rivers that belong entirely to the torrid zone display in their periodical movements that wonderful regularity which is peculiar to a region where the same wind brings almost always strata of air of the same temperature; and where the change of the sun in its declination causes every year at the same period a rupture of equilibrium in the electric intensity, in the cessation of the breezes, and the commencement of the season of rains. ”

“ Thus the meridional currents produced by overheating combine with the currents embracing the whole [p. 46] wind system of the earth, with the result of disseminating the excess of temperature and humidity of the torrid zone over the temperate and arctic zones, thereby producing the prevailing winds.
8. This is accomplished by the production of alternating local depressions and elevations of barometric pressure by the disturbance of indifferent equilibrium in the upper layers of the air. ”

“ As a whole, the portion of the continent embraced in the temperate zone is characterized by its pronounced seasonal changes, including wide extremes of heat and cold over large areas, and by its frequently sudden and strongly marked weather changes during short periods of time. It is a highly suggestive fact that of all the great climatic zones the one having the most changeable climate, the greatest extremes of heat and cold, and the most frequent storms should be the one in which man has reached the highest development both of body and mind. ”

“ Most springs in the temperate zone, without being warm in a remarkable degree, still possess a higher temperature than the average warmth of the air in the locality where they gush forth, while in the tropical zone they are frequently cooler—a proof that in both cases they issue from a depth independent of the fluctuating atmospherical influences of the surface. While these cool or cold springs, spread in immense numbers over the earth, attest the existence everywhere of a subterranean source of heat, the warm and hot 33springs remind us of its intensity at more considerable depths. ”

“ So far as we are able to sum up the results, it would appear that, in countries in the temperate zone still chiefly covered with wood, the summers would be cooler, moister, shorter, the winters milder, drier, longer, than in the same regions after the removal of the forest, and that the condensation and precipitation of atmospheric moisture would be, if not greater in total quantity, more frequent and less violent in discharge. ”

“ The advantage of the Temperate Zone is not only its moderate and adequate allowance of heat, but its contrast of seasons. Beyond the range of a vertical sun, grades of temperature change rapidly from latitude to latitude and from summer to winter. The seasons bring variety of activities, which sharply react upon one another. Manufactures were in their origin chiefly winter industries, as they still are in small isolated communities. ”

“ If light enough to ascend, their wealth of moisture is condensed as rain or snow along the mountain sides or summit, by the cold of the upper regions, as with your hand you squeeze a sponge; and, consequently, they topple over the Range dry and clear—to curse a vast region beyond with their sterility. If unable to ascend, they career along the western slope of the Mountains, and hover over the Coast Region generally, literally deluging Western Oregon and Washington, at certain seasons of the year, with rains and fogs. ”

“ The gradual narrowing of a valley tends to a more rapid lowering of the temperature for the obvious reason that the valley thereby resembles a basin almost closed, being thus a receptacle for the cold air-currents which descend from all sides. The bitterly cold furious gusts of wind which are often encountered in mountainous regions during night are simply the out-rush of cold air from such basins.
The two chief causes which tend to counteract these effects of terrestrial radiation are forests and sheets of water. ”

“ Land and sea breezes, although an unimportant climatic feature in these northern latitudes, are often of the highest importance in the Torrid Zone. The fresh pure sea breeze from over the ocean makes it possible for Europeans to live in many tropical climates where otherwise they would not keep their health. The land breeze, on the other hand, is apt to be an unhealthy wind in the tropics, especially when it blows off of swampy land. ”

“ When the uppermost ice layer has attained a temperature of 32° Fahrenheit, melting begins and moves rapidly inward from the glacier margin. In late spring the surface of the outer marginal zone is saturated with water, and this zone of slush advances inward with the season, but apparently never transgresses the inner border of what we have generally referred to as the marginal zone of the ice characterized by relatively steep slopes, crevasses, and nunataks. ”

“ There can be no question of the severity and length of the winters, but then we were told on all sides, with a concurrent testimony that could not be disputed or doubted, that the exceeding dryness of the climate renders the most excessive cold of very much less actual consequence to the sufferer than it would be in a country where there is moisture in the air. In fact in these Prairie regions, when the thermometer is perhaps 15° or 20° below freezing point, the cold is not so severely felt as with us when it is only 2° or 3° below 32°. ”

“ As the waters by which the springs are fed have often vast subterranean journeys to perform, their temperature is naturally independent of that of the seasons or of the changes of the atmosphere. Thus, cold springs occur in a tropical climate, when their subterranean channels descend from high mountains, and boiling sources gush forth in the Arctic regions when forced upwards from a considerable depth. ”

“ The temperate zone, so far 182 at least as North America is concerned, deserves its name only when the mean of the yearly changes in temperature is considered, as much of it is hotter in summer than equal areas between the tropics, and in winter over all of its northern half the cold is, at times, nearly or quite as intense as during the same season in the far north. ”

“ It has been observed that in the temperate zone the most violent winds occur, when neither the heat nor the cold common to such localities are at its maximum—that they generally extend over a considerable tract of country—and are accompanied by sudden and great falls in the mercury of the barometer. ”

“ The moist chilling fogs, and drizzling weather, which prevail almost perpetually along the coast, must necessarily render the parts adjacent very unfit for all the purposes of agriculture.
It is natural to suppose, that the severity of the climate must be in due proportion to the general sterility of the soil, of which it is probably the cause. The first time we saw this country was in the beginning of May, 1779, when the whole face of it was covered with snow, from six to eight feet deep. On the 6th we had snow, with the wind from the north-east. ”

“ The land, the real home and source of cold, acts as the great condenser of vapour, and snow and moisture of every kind, and lies under a deep covering of frozen snow till the colour of its walls and precipices reappears in April. The soil, in the stricter sense of the word, is frozen as hard as iron wherever it appears through the snow, and the mean temperature of Franz-Josef Land (about 3° F.) makes it highly probable, that the frost penetrates to the depth of a thousand feet. Great cold, calm weather, and clear atmosphere combined, are the characteristics of the interior of Arctic countries. ”

“ Dry whirlwinds of moderate size, but sometimes of considerable violence, frequently occur in clear weather when the percentage of humidity is small and when the vertical temperature gradient is unusually pronounced. In this case there may be strong agitation of the air, rendered visible at the earth’s surface by light débris on land, or boiling of the water at sea ”

“ The adjacent air, both on the north and south, being cooler, and, of course, heavier, would rush in to supply the place of the heated air. This air coming from the regions beyond the tropics would, in its turn, be heated, and rise on reaching the warmer equatorial regions, giving place to a fresh supply, which, it is easy to see, must be furnished by the descent of that portion of air formerly heated at the equator, raised into the cold regions of the sky, and forced into a regular circuit by fresh elevations of heated air. ”