United States or Mayotte ? Vote for the TOP Country of the Week !
The tropical forms all disappear in these zones, as the equatorial do in the tropical zones. The Warm Temperate zones exhibit the same disposition to retain some of the hardier and more abundant sub-tropical forms that characterize the other zones, in respect to their adjoining isotherms. Evergreen shrubs, heaths, cistusses, and leguminous plants are everywhere more abundant.
The line then curves fifteen degrees to the south across Siberia, rises again on the western coast of America, and falls once more as it advances towards the east. Again, 'the isotherms of Canada pass through Iceland, across about the middle of Norway and Sweden, St Petersburg and Kamtschatka.
The more impatient animals, for lack of necessary forage, must have crowded through the Isthmus only to be driven back by the tropical heats to their proper isotherms. But our warm temperate zone is now moving southward, and our scientific expedition is moving with it.
In winter the isotherms curve far to the north over the North Pacific and North Atlantic oceans; but over the intervening land they curve as much to the south. In summer the isotherms are almost reversed in position, at least as far as the land is concerned, for they bend to the north in the heart of the continent.
It will be instructive to search out the reasons for the remarkable contrasts in climate presented by different portions of the slope. The imaginary lines passing through points of equal temperature upon the earth are called "isotherms." These lines rarely accord in direction with the parallels of latitude, but curve far to the north or south.
The immigrants from Northern and Southern Europe have a disposition, in choosing their new homes, to follow latitude, or rather the isotherms; the North-men skirting the Canadian frontier and grouping themselves on the coldest side of Lake Michigan, while the Italians, Spaniards and French drift toward the Gulf States. The Irish and Germans are more cosmopolitan, each in a like degree.
And this view is undoubtedly the correct one. At all events, it entirely harmonizes with the facts of the biblical genesis, and obviates the necessity of accounting for the appearance of the same genera and species of plants or animals in the southern as in the northern hemispheres; in fact, their appearance in all parts of the globe, in corresponding isotherms, and under similar conditions of moisture and soil-constituents.
Arthur Renfrey before them, with the warm temperate zone north accurately laid down in its proper isotherms, as well as the different classes of vegetation peculiar to the two regions referred to, and some general conclusions of value to science might have been drawn therefrom. Besides, the fact of these similar antipodal flora was well known to many of them before this chart was issued.
But a closer classification now distinguishes them into the same number of zones as are marked, in approximate isotherms, on the earth's surface. Mr.
The irregular course of the isotherms is due to many causes. Among these are the distribution of the land and water, the direction of the prevailing wind, the position of the mountain ranges, and the elevation above sea-level. Fair weather over central portion of Pacific slope. Storm coming in upon coast of Washington
Word Of The Day