Penny Blood: Serial Sensation and Working-Class Entertainment — page 175: what you’re looking at

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

158 THE REVELATIONS OF (ow. XII. that their contour should be reduced to the semblance of in- verted mountains and alternating valleys, like those which characterise the upper surface of an Alpine region. The ratio of A :S may therefore be still regarded as nearly one of equality even in the lower portions. If we are at liberty to regard the rate beneath the moun- tain as approximately uniform, it is possible to estimate from the data the thickness of the crust at a place on the sea-level, and likewise the melting temperature at the bottom of it, if we assume a ratio for the densities of the crust and fluid sub- stratum. For generally let c be the depth of a point in the crust from the surface, a the temperature at that depth, 6 the temperature at the surface, r the rate of increase of te mperature in descending. Then we have the general relation, a—b — a veseee(L). If v be the rock-temperature in the tunnel, 6’ that at the top of the mountain, m the height of the mountain above the tunnel, 7’ the rate, we have in like manner whence r’ may be obtained from the observed data. Now suppose equation (1) to refer to some place A, any- where near the sea-level, where the total thickness of the crust is c, and the rate the usual one r. Then a=cr+ b. Similarly, if c’ be the thickness of the crust at the mountain, the temperatures at the bottom of the crust being the same at both places because it is the melting temperature, a=c'r +0. COMIC OOOKS.EO