Penny Blood: Serial Sensation and Working-Class Entertainment — page 137: what you’re looking at

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

td 120 DISTURBED TRACT. (cu. x. The experiments which M. Tresca made upon the flowing of plastic, and even very hard, substances have a bearing upon this subject. His paper has the appropriately paradoxical title, “De l’écoulement des corps solides’.’ In it he showed that solid, ductile, soft, or pulverulent, bodies can, without changing their state, flow in a manner analogous to that of liquids, when sufficiently great pressure is exerted on their surface. The substances were subjected to pressure confined in a rigid cylin- drical envelope, pierced at the bottom with a concentric orifice of varied dimensions. These experiments would lead us to expect, that the materials of the earth’s crust, when laterally compressed by a sufficient force, would “flow,” or be strained, vertically. What would be analogous to the stream lines in a liquid would represent the distortions of the rocks; thus might be produced cleavage, foliation, or contortion, according to the conditions of the rocks themselves, or of the neighbouring masses which adjoined them’. But although we cannot predict the exact manner in which the material will be arranged which constitutes the protu- berances that will be produced above and below the mean levels of the crust, yet we may arrive at some conclusion as to whether the material at any given level within the crust will on the average be sheared upwards or downwards by the compression. For this compression acting horizontally, will have no tendency in itself to determine whether the motion which it causes in an elementary portion of the crust subjected to its action shall be upwards or downwards. That 1 Comptes rendus, 1865, Vol. Lx. p. 1228. 2M. Tresca’s experiments appear to have led to the misconception, that great pressure causes solid substances to become liquid. A writer under the initials E. L. C. has said that, if the earth were of steel, at the depth of one or two leagues it would be of flowing steel, and that we should have to decide whether flowing steel was solid or fluid (Eng. Mechanic, Vol. x11. p. 254). But in M. Tresca’s experiments, one surface of the substance was subjected to enormous pressure, while the orifice from which it flowed was subject to none at all. This is quite a different case from that of the interior of the earth, where the pressure is alike in all directions. So far from great pressure rendering the interior fluid, it appears from the proved great rigidity of the earth as a whole, that it has an opposite effect. COMICOOOLKS @ (CO)