The polar and tropical worlds : a description of man and nature in the polar and equatorial regions of the globe . Sea, wherever it expands to a consider- THE ARCTIC SEAS. 57 ablo breadth, would be iusuffiuient to prevent its total congelation, if it werenot assisted by other physical causes. A magnificent system of currents iscontinually displacing the waters of the ocean, and forcing the warm floods ofthe trojiical regions to wander to the pole, while the cold streams of the frigidzone are as constantly migrating toward the Equator. Thus we see the GulfStream flowing through the broad gatewa
The polar and tropical worlds : a description of man and nature in the polar and equatorial regions of the globe . Sea, wherever it expands to a consider- THE ARCTIC SEAS. 57 ablo breadth, would be iusuffiuient to prevent its total congelation, if it werenot assisted by other physical causes. A magnificent system of currents iscontinually displacing the waters of the ocean, and forcing the warm floods ofthe trojiical regions to wander to the pole, while the cold streams of the frigidzone are as constantly migrating toward the Equator. Thus we see the GulfStream flowing through the broad gateway east of Spitzbergen, and forcingout a return current of cold water to the west of Spitzbergen, and throughDaviss Strait. • The comparatively wai-m floods which, in consequence of this great law ofcirculation, come pouring into the Arctic seas, naturally require some timebefore they are sufticiently chilled to be converted into ice; and as sea-waterlias its maximum of density, or, in other words, is heaviest a few degrees abovethe fieezing-point of Avater, and then necessarily sinks, the whole depth of the. OPEN WATER. sea must of course be cooled down to that temperature before freezing cantake place. Ice being a bad conductor of heat, likewise limits the process ofcongelation ; for after attaming a thickness of ten or fifteen feet, its growth isvery slow, and probably even ceases altogether; for when floating fields, orfloes, are found of a greater thickness, this increase is due to the snow thatfalls upon their surface, or to the accumulation of hummocks caused by theircollision. Thus, by the combined influence of these various physical agencies, boundshave been set to the congelation of the Polar waters. Were it otherwise, theArctic lands would have been mere uninhabitable wastes; for the existence ofthe seals, the walrus, and the whale depends upon their finding some open wa-ter at every season of the year; and deprived of this resource, all the Esqui-maux, whose variou
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