Penny Blood: Serial Sensation and Working-Class Entertainment — page 242: what you’re looking at

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

CH. XVII. ] EXPLAINED. produce compression, and the extravasation of water-substance from beneath the crust may also play its part, but it appears 225 that neither of these, nor yet both together, can account for an 34 appreciable portion of the grand result. Whether the mode of action suggested in Chapter XV., more immediately derived from the same source, is capable of doing so is not easily decided. It must be remembered that the amount of compression calculated in Chapter XIII, as requisite to account for the existing eleva- tions, refers to the whole time elapsed since they began to be formed, But the act of compression connected with the forma- “ tion of the dykes beneath any given region would be confined — to a comparatively limited geological period. We should there- ' fore expect to find in them evidence of compression belonging, , as regards time, only to a part of the whole amount required. On this account, ocular evidence of a smaller amount of expan- ‘ sion might be deemed sufficient. On the other hand, our theory , localises the compressing force, and on this account we should | look, as regards space, for evidence of a larger amount than if ' the expansion producing it were evenly distributed. Another difficulty arises, namely, that the width of the dykes will be too large a measure of the expansion arising from them, because the ‘ fissures will have been partly opened by the contraction of the rocks themselves, and only partly forced asunder by the pres- sure to which we are now attributing compression. It cannot be denied that, as the former three hypotheses have proved in- adequate when brought to numerical tests, so, if it could be done, might also this last. Still the estimate at the end of Chapter XV. may be considered favourable. The theory possesses the advantage over the others that, if the lateral pressure be deemed sufficient, the range through which it is capable of acting is practically sufficient. These conditions are the exact reverse of the former; for in them there could be no question regard- ing the sufficiency of the lateral force, but the range was found to be insufficient. In the present case, the difficulty consists in applying any test to see whether the phenomena indicate that the force now appealed to can in fact have acted through a sufficient range to have produced the requisite compression. F, | 15 i. (CO) NOO SS (CO)