Penny Blood: Serial Sensation and Working-Class Entertainment — page 247: what you’re looking at

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

230 | ' MR MALLETS [cH. XVIII. This is Mr Mallet’s equation (6), § 102, where he takes w to be the mass of one cubic foot of rock, and of which we have for clearness given a demonstration. His experiments gave for the mean value of s the number 0°199; and for the mean weight w of a cubic foot of rock 177 Ib. The mean number of British units of heat developed by crushing one cubic foot of the harder rocks is estimated by him at 5650; and it appears upon calculating the value of ¢, that the mean temperature by which a cubic foot of such rock would be so raised is 172’ F. Or if we take the particular kinds of rock selected by Mr Mallet (§ 133), these means are found by him to be 6472 and 183"74F. And if the rock was previously at 300° F., taking 2000° as the fusing tem- perature, he finds 0°108, or rather above one-tenth, as the frac- tion of a cubic foot of rock which the heat developed by crushing one cubic foot of rock could fuse. Or, to put it otherwise, it would require the heat developed by crushing ten volumes of rock to fuse about one. Here we meet with a remarkable discrepancy between the results given in the paper in the Philosophical Transactions and those previously given in the introductory sketch to the same author’s translation of Palmieri’s “Vesuvius’,” for it is there stated that using the mean of 6472 units of heat as derived from crushing one cubic foot of rock “each cubic mile of the mean material of such a crust, when crushed to powder, deve- lopes sufficient heat to melt 0876 cubic miles of ice into water at 32°, or to raise 7°600 cubic miles of water from 32° to 212° F., or to boil off 1124 cubic miles of water at 32° into steam of one atmosphere, or, taking the average melting point of rocky mixtures at 2000° F., to melt nearly three and a half cubic miles of such rock, if of the same specific heat.” It 1s obvious that it makes no difference in the ratio, whether the unit be a cubic mile, or a cubic foot, or a cubic inch. So that the state- ment here amounts to saying, that the crushing of one cubic foot would melt 34 cubic feet, instead of 0°108 of a cubic foot ; or more than 32 times as much as subsequently stated in the 1 p. 69. ‘There is a foot-note to the paper in the Transactions which speaks of a modification of § 102. Th.s may be connected with the discrepancy re- ferred to. commiclsoolkks (CO)