Penny Blood: Serial Sensation and Working-Class Entertainment — page 224: what you’re looking at

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

cH. xv.] COMPRESSION AND VOLCANIC ACTION. 207 the pre-existing crust. But the solidified lava is a new ac- cession to it. If % (jf) be the volume of the lava injected into the fissures, we shall have by the figure, kl + (f) =kl+% (a) —% (6) + 2 (8) — 3% (2), or > (f) =>% (a) —% (6) + & (8) — (a). If e were the compression which would produce a similar tract out of the length 2 and thickness & of crust we perceive from this expression that 3 (f) = kle. We have estimated the value of e to be in the case of nature’ about 0:02; taking the thickness of the crust as 25 miles. With these ealuon we get = (f) = 2; that is to say the vertical sectional area of the dykes, occurring in each horizontal mile of crust 25 miles thick, would be half a square mile, or one-fiftieth of the whole sectional area. This does not appear unreasonable, especially when we remember that the dykes will be most numerous and widest in the lower parts of the crust, which are probably never brought under our observation. 1 p. 179. GONG oOo SS (CO)