. An account of the Arctic regions [microform] : with a history and description of the northern whale-fishery. Natural history; Sciences naturelles. I:. ,;,, â . , feet. The degree of impregnation of the one-inch cubes of ash, produced by immersion to the depth of 2058 feet to 6348 feet, varies irregularly, but is evidently as great at the depth of 2058 feet, as un- der any superior pressure; so that it is probable that the greatest permanent impregnation by pres- sure, of such open-grained woods as ash, elm, fir, &c. is produced at the depth of 300 or 400 fathoms. Hence it is clear that n
. An account of the Arctic regions [microform] : with a history and description of the northern whale-fishery. Natural history; Sciences naturelles. I:. ,;,, â . , feet. The degree of impregnation of the one-inch cubes of ash, produced by immersion to the depth of 2058 feet to 6348 feet, varies irregularly, but is evidently as great at the depth of 2058 feet, as un- der any superior pressure; so that it is probable that the greatest permanent impregnation by pres- sure, of such open-grained woods as ash, elm, fir, &c. is produced at the depth of 300 or 400 fathoms. Hence it is clear that no use can be made of this effect of pressure, for determining the depth, unless it be within 2000 feet of the surface; and even in this limit, the results may be uncertain. From a comparison of column vii. with xiii., and column IV. with xv., it appears, that an effect of the impregnation of the wood with sea-water, was to in- crease its dimensions, as well as its specific gravity ; each specimen, on an average, having swelled cubic inch in every solid inch of original dimen- sions, and gained "^4 giains on every 100 grains of ori- ginal weight; that is, an increase of one-twentieth in size, and twenty-one twenty-fifths in weight. I have little doubt, but the degree of impregna- tion always increases with the increase of pressure; but the air contained in the pores of the wood, which is never wholly disengaged, exerting an ex- pansive force when the load of pressure is removed, forces part of the water out again. This was clear- ly discernible in some of the specimens used in the foregoing experiments, at the moment they were hauled up, their surfaces being covered with a thin |)ellicle of froth. Hence pieces of fir sometimes be- !«â ⢠â i--. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original
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