Penny Blood: Serial Sensation and Working-Class Entertainment — page 141: what you’re looking at

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

124 DISTURBED TRACT. [cH. ° In this case then the neutral zone would be at one-third oz the depth. } In finding the position of the neutral zone no assumption has been made respecting the value of k. So long as the crust at the place under consideration was not under constraint, but in equilibrium as a floating body, the neutral zone would hold the same relative position within it. So that if this condition of flotation remained fulfilled it would be always horizontal. For the purpose we have in view it will be sufficiently accurate to assume, that it occupies a position whose distances from the upper and lower surfaces of the crust, whether before or after compression, are always in the same ratio. It is also observable that the position of this zone does not depend upon the absolute value of the frictional force, so long as it can be expressed as a function of the depth multiplied by the value which the friction has at the surface. If however the friction were to vanish, which it would do if the material were to become liquid, we should have A indeterminate. The signi- fication of this appears to be, that the tendency of the liquid at every depth would then be indifferently to move upwards or downwards, and therefore it would be affected with confused internal currents, somewhat similar to convection currents, Now it will be observed that, since the shear, whether up- wards or downwards, increases continually as we get further from the neutral zone, it follows that if there were to be a relative motion, in the opposite direction to that which they actually have, impressed upon the particles at any given level, that level would become a neutral zone relatively to the particles above or below it. If then the material above or below any zone were to become liquid, 1t would behave under this relation as the whole crust would behave if it were liquid, and would be affected with confused currents. This consideration goes far to explain the confused contortions constantly observable in highly metamorphosed rocks; which are supposed to have been softened by heat, and consequently to have approached the condition of a liquid. COMIC OOOKS.EO OE ge —_—_—_ = re en nA EPS — nen Sar