. A treatise on rocks, rock-weathering and soils;. Petrology; Soils. ACTION OF WATER AKD ICE 275 composed. This creeping process he ascribed wholly to the expansive action of included water passing into the condition of ice, the expansion taking place laterally and the material being pushed down the slope along the line of least resistance. Mr. C. Davidson has since taken up the subject experimentally;. Fig. 24.—Showing direction and rate of motion of soilj tlie arrows showing, hj their relative lengths, the rate of movement at various points, a, soil; b, bedrock. and shown that the amount of
. A treatise on rocks, rock-weathering and soils;. Petrology; Soils. ACTION OF WATER AKD ICE 275 composed. This creeping process he ascribed wholly to the expansive action of included water passing into the condition of ice, the expansion taking place laterally and the material being pushed down the slope along the line of least resistance. Mr. C. Davidson has since taken up the subject experimentally;. Fig. 24.—Showing direction and rate of motion of soilj tlie arrows showing, hj their relative lengths, the rate of movement at various points, a, soil; b, bedrock. and shown that the amount of the creeping could be accounted for by the ordinary laws of gravity, the frost, by its expansion, raising the individual particles a slight distance, and, on thaw- ing, allowing them to drop back again a greater or less distance down the slope, according to the angle of inclination. Dr. Milton Whitney has, however, shown^ that there is an almost continual movement among soil particles, dependent upon meteorological conditions quite aside from those involved in freezing and thawing. The creeping appears therefore to be but the manifestation, in mass, of the inclination of each indi- vidual particle to slide down the slope. The accumulations of talus at the foot of every cliff and on the slopes of hills and mountains are matters of such every-day observation as to need no mention in detail. (2) The Action of Water and Ice.^ — The power of a stream to transport rock debris depends naturally upon its volume and the rapidity of its current. This, on the supposition that the character of the sediment to be transported remains the same. According to the calculations of Hopkins, as quoted by ^ Some Physical Properties of Soils, Bull. No. 4, U. S. Weather Bureau, 1892. ^Students are referred to Professor E. B. Salisbury's article on Agencies which Transport Material on the Earth's Surface, Journal of Geology, Vol. Ill, 1895, p. Please note that these images are extracted from s
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectpetrolo, bookyear1913
