. Narrative of discovery and adventure in the polar seas and regions [microform] : with illustrations of their climate, geology, and natural history ; and an account of the whale-fishery. Natural history; Sciences naturelles. CLIMATE. 31 or alcohol: Far from dilating uniformly,âa property which fits the latter substances for the construction of thermometers,âit swells from the point of congelation, or rather a very few degrees above it, with a rapid pro- gression to that of boiling. Near the limit of its greatest contraction, the volume of water is scarcely affected at all by any alteration of
. Narrative of discovery and adventure in the polar seas and regions [microform] : with illustrations of their climate, geology, and natural history ; and an account of the whale-fishery. Natural history; Sciences naturelles. CLIMATE. 31 or alcohol: Far from dilating uniformly,âa property which fits the latter substances for the construction of thermometers,âit swells from the point of congelation, or rather a very few degrees above it, with a rapid pro- gression to that of boiling. Near the limit of its greatest contraction, the volume of water is scarcely affected at all by any alteration of heat. When the surface of the ocean is depressed to a temperature between 28 and 44 degrees of Fahrenheit's scale, it remains almost stagnant, and therefore exposed to the full impression of external cold. Hence the Polar Seas are always ready, under the action of any frosty wind, to suffer congelation. The annual variations of the weather are in those seas expended on the superficial waters, without disturbing the vast abyss below. Contrary to what takes place under milder skies, the water drawn up from a con- siderable depth is often warmer within the Arctic circle than what lies on the surface. The floating ice ac- cordingly begins to melt generally on the under side, from the slow communication of the heat sent upwards. These deductions are confirmed by ths results of the nicest astronomical observations. Any change in the temperature of our globe would occasion a corresponding change of volume, and consequently an alteration in the momentum of the revolving mass. Thus, if from the accession of heat the earth had gained only a millionth part of linear expansion, it would have required an in- crease of five times proportionally more momentum to maintain the same rotation. On this supposition, therefore, the diurnal revolution would have been re- tarded at the rate of three seconds in a week. But the length of the day has certainly not varied one second in a year since the
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Keywords: ., bookcentury1800, bookdecade1840, books, booksubjectnaturalhistory
