Penny Blood: Serial Sensation and Working-Class Entertainment — page 216: what you’re looking at

Machine-transcribed from the original scan — historical spelling and the odd misread are preserved.

cH. xv.] COMPRESSION AND VOLCANIC ACTION. 199 Indeed there are points of analogy so close between the cir- cumstances of ice resting upon water, and such a crust as we have supposed resting upon a fluid substratum, that we may expect to receive suggestions for explaining the phenomena of crust movements from the behaviour of ice. In both cases the floating substance is but slightly less dense than that upon which it floats. In both cases the one is incorporated with the other by congelation. In both cases the floating substance has a considerable amount of rigidity, but yields somewhat freely to differences of pressure when sufficient time is allowed. These analogies have been noticed by many. Thus, in travelling across the frozen sea to the north of Spitzbergen, Prof. Nordenskidld gives this description of the condition of the ice and deduces conclusions from it regarding movements in the crust of the earth : “The ice we passed is formed not of colossal blocks or ice- bergs, but of angular blocks of ice, not waterworn, piled loosely over each other, so as to form pyramids, or walls of ice, up to thirty feet high, which were so close to each. other that the space between them was frequently not large enough for our tent. “The cause of the formation of these ice-walls, which were also observed by Wrangel on the north coast of Siberia, is pro- bably to be sought for in the changes of volume which ice undergoes when its temperature 1s changed. According to Plucker and Geissler the linear expansion-toefficient of ice is = 0:0000528. If, therefore, ice at 0° C. be cooled to —15°C., cracks must arise which, for 1,000 metres, have a breadth of thirty-two inches. The cracks naturally freeze together im- mediately afterwards,” [which must mean that they become filled with water and the water in them freezes], “and when the ice 1s again warmed, for instance to —5°C., a piling-up must take place of twenty-one inches per kilometre. During the course of the winter this phenomenon is repeated innumerable times, one layer of ice being piled upon another, till the whole ice-field forms a confused mass of blocks heaped up against each other. Similar forces are also in operation in the crust of the earth, with less intensity, indeed, in consequence of the smaller COLA @ NOO (CO)