Penny Blood: Serial Sensation and Working-Class Entertainment — page 23: what you’re looking at

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

6 ON UNDERGROUND TEMPERATURE. [oH. 1. in the bore were taken with much precaution, under the direc- tion of Herr Eduard Dunker, Inspector.of Mines. <A résumé of his paper upon them will be found in “Nature,” Vol. xv. p. 240, 1877, as contained in the “ Ninth Report of the British Asso- ciation Committee on Underground Temperature.” In Vol. x11. p. 545 of the same publication (1875) there had previously ap- peared a notice of a contribution by Prof. Mohr, of Bonn, to the “Neues Jahrbuch fiir Mineralogie” (1875), in which that gentleman had commented upon the law of increase which he supposed to be deducible from the observations made in this bore-hole. The result at which he arrived was remarkable enough, and, if it could not have been explained away, would have justified the conclusion which he drew from it, which was that the source of heat within the crust of the earth was situated within the crust itself, for that after a certain depth was reached—which he put at 5170 feet—the increase would be nil. However, in the Report of the British Associa- tion just published, it 1s explained how this result had been arrived at, and it is distinctly shown that Prof. Mohr’s con- clusion was in reality not based upon the original observations themselves, but that it arose from the form of an empirical mathematical formula, representing a parabola, which Dunker had assumed to express the law. In fact it had been implicitly assumed that the increase would come to an end, and all that Mohr did was to find out at what depth it would do so, sup- posing that assumption true. This bore-hole, from the favourable circumstances already referred to, and the care with which the observations were made, deserves full consideration. The temperatures were taken in two manners. In one set of observations the tem- perature of the water in the bore-hole was observed with a suitable thermometer; in the other an apparatus called a geo- thermometer was lowered, which cut off a portion of water from that above and below it by two disks or bags. A thermometer was enclosed in the space between the disks, and, after the thermometer had been down not less than ten hours, the tem- perature shown by it was assumed to be that of the rock at the corresponding depth. This was found to differ sometimes by commiclsoolkks (CO) S