Caxton's Book: A Collection of Essays, Poems, Tales, and Sketches.

by W. H. Rhodes

Thirdly. That the lavas taken from all parts of the world, when subjected to chemical analysis, indicate that they all proceed from a common source; and

Fourthly. On no other hypothesis can we account for the change of climate indicated by fossils.

The rate of increase of heat in the Dudzeele shaft was no less than one degree Fahrenheit for every thirty feet English measure.

At the time of recommencing sinking in the shaft on the 10th of April, 1849, the perpendicular depth was twenty-three hundred and seventy feet, the thermometer marking forty-eight degrees Fahrenheit at the surface; this would give the enormous heat of one hundred and twenty-seven degrees Fahrenheit at the bottom of the mine. Of course, without ventilation no human being could long survive in such an atmosphere, and the first operations of the commission were directed to remedy this inconvenience.

The report then proceeds to give the details of a very successful contrivance for forcing air into the shaft at the greatest depths, only a portion of which do we deem it important to quote, as follows:

The width of the Moer-Vater, or Lieve, at this point, was ten hundred and eighty yards, and spanned by an old bridge, the stone piers of which were very near together, having been built by the emperor Hadrian in the early part of the second century. The rise of the tide in the North Sea, close at hand, was from fifteen to eighteen feet, thus producing a current almost as rapid as that of the Mersey at Liverpool. The commissioners determined to utilize this force, in preference to the erection of expensive steam works at the mouth of the mine. A plan was submitted by Cyrus W. Field, and at once adopted. Turbine wheels were built, covering the space betwixt each arch, movable, and adapted to the rise and fall of the tide. Gates were also constructed between each arch, and a head of water, ranging from ten to fifteen feet fall, provided for each turn of the tide—both in the ebb and the flow, so that there should be a continuous motion to the machinery. Near the mouth of the shaft two large boiler-iron reservoirs were constructed, capable of holding from one hundred and fifty thousand to two hundred thousand cubic feet of compressed air, the average rate of condensation being about two hundred atmospheres. These reservoirs were properly connected with the pumping apparatus of the bridge by large cast-iron mains, so that the supply was continuous, and at an almost nominal cost. It was by the same power of compressed air that the tunneling through Mount St. Gothard was effected for the Lyons and Turin Railway, just completed.

The first operations were to enlarge the shaft so as to form an opening forty by one hundred feet, English measure. This consumed the greater part of the year 1849, so that the real work of sinking was not fairly under way until early in 1850. But from that period down to the memorable 5th of November, 1872, the excavation steadily progressed. I neglected to state at the outset that M. Jean Dusoloy, the state engineer of Belgium, was appointed General Superintendent, and continued to fill that important office until he lost his life, on the morning of the 6th of November, the melancholly details of which are hereinafter fully narrated.

As the deepening progressed the heat of the bottom continued to increase, but it was soon observed in a different ratio from the calculations of the experts. After attaining the depth of fifteen thousand six hundred and fifty feet,—about the height of Mt. Blanc—which was reached early in 1864, it was noticed, for the first time, that the laws of temperature and gravitation were synchronous; that is, that the heat augmented in a ratio proportioned to the square of the distance from the surface downward. Hence the increase at great depths bore no relation at all to the apparently gradual augmentation near the surface. As early as June, 1868, it became apparent that the sinking, if carried on at all, would have to be protected by some atheromatous or adiathermic covering. Professor Tyndall was applied to, and, at the request of Lord Palmerston, made a vast number of experiments on non-conducting bodies. As the result of his labors, he prepared a compound solution about the density of common white lead, composed of selenite alum and sulphate of copper, which was laid on three or four thicknesses, first upon the bodies of the naked miners—for in all deep mines the operatives work in puris naturalibus—and then upon an oval-shaped cage made of papier mache, with a false bottom, enclosed within which the miners were enabled to endure the intense heat for a shift of two hours each day. The drilling was all done by means of the diamond-pointed instrument, and the blasting by nitro-glycerine from the outset; so that the principal labor consisted in shoveling up the debris and keeping the drill-point in situ.

Before proceeding further it may not be improper to enumerate a few of the more important scientific facts which, up to the 1st of November of the past year, had been satisfactorily established. First in importance is the one alluded to above—the rate of increase of temperature as we descend into the bowels of the earth. This law, shown above to correspond exactly with the law of attraction or gravitation, had been entirely overlooked by all the scientists, living or dead. No one had for a moment suspected that heat followed the universal law of physics as a material body ought to do, simply because, from the time of De Saussure, heat had been regarded only as a force or vis viva and not as a ponderable quality.

But not only was heat found to be subject to the law of inverse ratio of the square of the distance from the surface, but the atmosphere itself followed the same invariable rule. Thus, while we know that water boils at the level of the sea at two hundred and twelve degrees Fahrenheit, it readily vaporizes at one hundred and eighty-five degrees on the peak of Teneriffe, only fifteen thousand feet above that level. This, we know, is owing to the weight of the superincumbent atmosphere, there being a heavier burden at the surface than at any height above it. The rate of decrease above the surface is perfectly regular, being one degree for every five hundred and ninety feet of ascent. But the amazing fact was shown that the weight of the atmosphere increased in a ratio proportioned to the square of the distance downward.... The magnetic needle also evinced some curious disturbance, the dip being invariably upward. Its action also was exceedingly feeble, and the day before the operations ceased it lost all polarity whatever, and the finest magnet would not meander from the point of the compass it happened to be left at for the time being. As Sir Edward Sabine finely said, "The hands of the magnetic clock stopped." But the activity of the needle gradually increased as the surface was approached.