Penny Blood: Serial Sensation and Working-Class Entertainment — page 249: what you’re looking at

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

232 MR MALLET’S | [cH. XVIIB. a,, a, a,, &c., by which the weak portions have been shortened; while Pa,, Pa,, Pa,, &c. are the portions of work done at these places. And these taken together make up Pa, since a,ta,ta,+c&e. =a. We see, then, that the work must be confined to these places ; for if there were work done elsewhere we should have more work than Pa, which is impossible. Hence the work convertible partially into heat takes place at all these places, and at each in proportion only to the yielding, and nowhere else; so that it cannot be localized at any one place. We may then conclude that, unless the heat got out of crushing any portion of rock is sufficient to fuse that particular portion, none will be fused. Indeed we may go so far as to assert that, if Mr Mallet’s experi- ments give the amount of heat which can be obtained by crushing rock, and the heat so obtained can fuse it, then the cubes experimented upon ought to have been fused. But it is scarcely satisfactory to leave the question at this point. It is conceivable that the pressures, which were experi- mentally applied to the cubes of rock, might be far exceeded within the earth’s crust, if compression were caused there by the contraction assumed in the theory under discussion; which it must be recollected is quite opposed to the results obtained in the preceding Chapters. Let us then survey the supposed con- ditions of the problem. A contracting globe induces in its en- veloping crust a state of compression, which owes its existence to the gravitation of the whole towards the centre of the figure. The interior goes on contracting until the compressing force accumulates sufficiently to cause a movement of some kind among the particles of the crust, be it crushing, or faulting, or corrugation, or what not; and the motion being arrested, the work becomes transformed into heat, This heat, as already proved, can be developed only at those places where the move- ment occurs. The question is whether it would be sufficient to give rise to avolcano. If some places are weaker than others, the movement would necessarily occur at them. Let there be several such, which for simplicity we will suppose to be situated at points upon a great circle. The force of compression will go - . GOnieaooks (CO) ee ; —_——. 1 WOO nls