Penny Blood: Serial Sensation and Working-Class Entertainment — page 144: what you’re looking at

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

CH. x. | DISTURBED TRACT. 127 This however depends upon the constitution of the crust. It h may therefore happen that gph + | fdz may be greater for a 0 small value of 2 when / is great, than for a considerably larger value of k when /f is small, that is the strength of the crust may present a greater obstacle to shearing than its thickness. This confirms what has already been said at p. 119 respecting a relation between the amount of vertical shear and the strength of the crust. By the favour of Messrs Macmillan and of the proprietors of La Nature, one of the woodcuts is exhibited overleaf represent- ing the results of some interesting experiments made by Prof. A. Favre of Geneva. The following description is from the trans- lation given of Prof. Favre’s article in Nature, Vol. x1x. p. 108. “‘T placed the layer of clay employed in these experiments on a sheet of caoutchouc, tightly stretched, to which I made it adhere as much as possible; then I allowed the caoutchouc to resume its original dimensions. By its contraction the caoutchouc would act equally on all points of the lower part of the clay, and more or less on all the mass in the direction of the lateral thrust....... " “The arrangement of the apparatus 1s very simple. A sheet of India rubber 16 mm. in thickness, 12 cm. broad, and 40 cm. long, was stretched, in most of the experiments, to a length of 60cm. This was covered with a layer of potter's clay in a pasty condition, the thickness of which varied, according to the experiments from 25 to 60mm. It will be seen from the di- mensions indicated that pressure would diminish the length of the band of clay by one-third. This pressure has been exerted on certain mountains of Savoy....... ” “The strata, which appear to divide the masses of clay, and which are represented im the figures, are not really strata, but simply horizontal lines at the surface of the clay”—probably he means ruled along the side of the mass before the compression was allowed to act. After describing the varied appearances, he observes, “The strata are less strongly contorted in the lower parts than in the neighbourhood of the upper surface. They are disjoined in certain parts by fissures or caverns. They are tra- versed by clefts or faults inclined or vertical. All these deforma- GONG oOo SS (CO)