Penny Blood: Serial Sensation and Working-Class Entertainment — page 117: what you’re looking at

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

100 CRUST NOT FLEXIBLE, (cH. IX. datum level, But it has already served a most important pur- pose by enabling us to prove that the inequalities, as we now see them, are far greater than can be accounted for upon the supposition of a solid globe contracting from cooling only. Assuming then that a solid crust rests in corrugations upon a fluid layer, which is capable of yielding to such forces as the gravitation of the crust exerts, we have to consider the condi- tions of its equilibrium. Now the disturbances which we see that it has experienced, to the greatest depths which denudation exposes to observation, would lead us to suppose that, when once disturbed in lengths of any extent, it might perhaps be considered flexible. Moreover, if it rests in corrugations upon _ the subjacent fluid, it must be in unstable equilibrium; that is, the corrugations can have no particular relation to the places where they occur, but might exist equally well at some other. Here we should at once encounter a condition which would render oscillations of the surface possible, provided we could account for the disturbance of the position of equilibrium. It will however be seen that the results of the following investigation are so remotely akin to natural appearances, that it must follow that the assumption of the flexibility of the crust is not true to fact. So that rigidity appears to play an important part in determining the position and form of the in- equalities. This negative result is of itself of sufficient import- ance to make it worth while to give the investigation, irrespec- tive of the intrinsic interest of the problem from a mathematical point of view. In order to obtain some insight into the general character of the corrugations, we will begin by enquiring what form would be assumed by a heavy flexible crust, resting upon a liquid within a rectangular trough shorter than the crust, for this would give an approximate idea of the contour of the surface upon the course of a section of the sphere perpendicular to its surface and cutting a set of corrugations at right angles. It may be assumed that the trough and crust were originally of the same length, and that the corrugations have been pro- duced by the ends of the trough having been made to approach each cther. COLA @ NOOKS (CO) ) ——)