Penny Blood: Serial Sensation and Working-Class Entertainment — page 195: what you’re looking at

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

178 AMOUNT OF COMPRESSION. (cH. XIII. therefore admit that, if the continental areas have been gradually elevated by compression out of sub-oceanic crust, a diminution of density must have been a consequence of their elevation. For this we shall attempt to account hereafter. If we suppose that, instead of the existing denser crust beneath the ocean, we substitute a crust of the same thick- ness as at the sea-board, and of the density p, and omit the consideration of the ocean, then the compression of such a crust parallel to the direction of its surface (which would be the same as the existing sea-level) would, on a section of unit of width, produce elevations of the mass pkle for the compression e. And on the supposition that these occurred in the same areas that the existing elevations do occur, their mass would be the same as that of the existing elevations. The radius to the surface of such a crust would be the same as to the surface of the existing ocean. We are therefore at liberty to make use of this suppo- sititious case for the purpose of obtaining an approximate value for the compression, in order to avoid the difficulties which would occur in reasoning about a crust of density differing in different regions. Reverting therefore to our expression for the value of e, it is evident that the second term must be omitted, for that depends upon the amount of water lying upon the surface. of the dis- turbed area. It reduces therefore to | r 2 (A’) —% (B’) om (Opt) eae Next in estimating = (A’) — 2% (B’) we must omit the conside- ration of the elevation of the sea-level above the mean level of the crust beneath the ocean, using the surface of the ocean as if it were the mean level. Consequently the part involving 6, or 3°5, will disappear, and we have > (A’) — & (B’) = 52 x 10° x 0°19 cubic miles. We must also use for & the value of the thickness at the sea- level, which we put at 25 miles. If we now substitute the values which we have been using for p and o, we get for the mean coefficient of compression } e = 0:0105. COMIC OOOKS.EO J