Penny Blood: Serial Sensation and Working-Class Entertainment — page 253: what you’re looking at

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

236 MR MALLETS [cH, XvIIt. Hence we find for the work for one year, work = 76908 foot pounds ; and dividing by Joule’s equivalent, 772 ; heat per square foot = 99 units. The corresponding value for BB’ will be 5333 miles. Now, according to Mr Mallet’s results in his principal memoir, § 133 (1) and (6), we are informed that 6472 units of heat would fuse 0°108 cubic foot of mean rock previously at 300° F., taking 2000° as the fusing temperature. Hence with a solid earth, according to our calculation, a lwnit greater than the greatest possible gives 0:0015 cubic foot of mean rock that could be fused annually for each square foot of the plane of vertical section. With this value it would take a thousand years to fuse one vertical slice of a foot and a half thickness within the range of crust defined by the distance BB’, or 5333 miles, on a great circle of the sphere. But the place of weakness cannot but have a considerable width throughout which the heat would be distributed. If, then, it were, say, a mile wide, the number of units of heat to each cubic foot would be ,28,, or about 0:02 unit. The force of compression, besides the work of crushing at A where the yielding takes place, also does work over the plane of shearing in overcoming adhesion and friction. Let the whole force expended in overcoming adhesion and friction along BB’ be » BB’. The space moved over increases from nothing at B and B’ to eAB and eAB' at A. The mean is = - Hence the work along this plane is p BB'x — = Qy! _ Py Pre-Pay eix—P. Puy PP Pe And making the same suppositions as before for a superior limit, this becomes on the whole plane P* Qu’ —, ek’. aa COMIC OOOKS.EO