Penny Blood: Serial Sensation and Working-Class Entertainment — page 255: what you’re looking at

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

238 MR MALLET’S [cH. xv1Il. (1) That the contraction from cooling would take place in the matter of the nucleus and not in the crust, for this suppo- sition is involved in Mr Mallet’s value for the contraction. (2) That the above circumstance would allow the coeffi- cient of contraction to be nearly four times as large as on the more probable supposition. (3) That the pressure increases to the utmost attainable value, viz. that of a column of rock 2000 miles long, before yielding takes place. (4) That when yielding does take place, the pressure at the place of yielding is entirely satisfied. The above assumptions, besides making the amount of heat impossibly great, also localize it to an impossible degree, as may be seen by observing that BB’ would be lessened by diminishing P,, and also by increasing P,; that is, by lessening the pressure which causes the yielding, and by increasing the. pressure at the place of yielding after the compression has taken place. The calculations indicated above will be found given at greater length in the Author’s paper on this subject in the “ Philosophical Magazine’,” together with an extension of the investigation to some further hypotheses as to the crust sliding over a fluid nucleus. But it is thought unnecessary to repro- duce more here to show that the theory does not account satis- factorily for volcanic phenomena. We see then that Mr Mallet’s own experimental mode of esti- mating the pressure requisite for crushing the strata cannot give rise to sufficient heat for the purpose; and that if we go far beyond this, and use in forming our estimate the utmost pressure under the circumstances conceivable, we still fall far short of obtaining the requisite amount of heat. Accordingly, we are 1 Fourth series, Vol. 50, p. 302, 1875 (in which occurs the following erratum. At p. 316, line 6, insert k, for ‘11 mile” read ‘‘538 miles,” and dele the follow- Ing line). See also Mr Mallet’s replys fifth series, Vol. 1. p. 19, and the Author's rejoinder, Ibid, p. 138, COLA @ NOOKS ACO