Penny Blood: Serial Sensation and Working-Class Entertainment — page 245: what you’re looking at

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

228 MR MALLET'’S (cH. XVIII. whether this contraction exists, at least to such an extent as to produce any appreciable movements of the crust during such periods of time as history embraces, Yet volcanic phenomena are of daily occurrence. This appears to dispose of the theory tn limine. Nevertheless it is possible that this argument against it may not meet with general acceptance, and it is therefore desirable to examine Mr Mallet’s theory upon his own assumptions. No one can study the paper, in which the theory 1s pro- pounded, without admiring the amount of knowledge displayed in it, and the numerous and laborious experimental investiga- tions which he undertook to form the basis of his theory. The records of these alone will render his work of lasting value. Nevertheless we cannot avoid the conviction, that they do not warrant the conclusions which he has drawn from them. The experiments which form the foundation of the theory may be shortly thus described :— Cubes of rock of sixteen different kinds, varying in respect of hardness from soft oolite to hard porphyry, were carefully cut into cubes of 14 imches on the edge. These were then crushed by means of a powerful lever, under a cylindrical piston or plunger of 34 inches diameter. The cubes of rock appear not to have been confined at all laterally, so that, when they gave way, they were compressed into a cake of powder beneath the plunger. The pressure upon each square inch of the face of the cube was calculated from the accurately known pressure laid upon the plunger, and the vertical descent of the plunger, while the crushing was going on, was also carefully measured. These multiplied together gave the “work” of crushing, and by divid- ing the work so obtained by Joule’s equivalent the correspond- ing quantity of heat was calculated, it being assumed that all the work was transformed into heat. If we consider the summary of the series of experiments in crushing cubes of rock’, it 1s evident that the vertical descent 1 Op. cit. Tab. 1. column 19, p. 187. COMIC OOOKS.EO