Caxton's Book: A Collection of Essays, Poems, Tales, and Sketches Part 19

So flock in millions sons of honest toil, From ev'ry country, to their native soil; Exiles of Erin, driven from her sod, By foes of justice, mercy, man, and G.o.d!

aerial chariots spread their snowy wings, And drop torpedoes in the halls of kings.

On every breeze a thousand banners fly, And Erin's seraph swells the battle-cry:-- "Strike! till the Unicorn shall lose the crown!

Strike! till the Eagle tears the Lion down!

Strike! till proud Albion bows her haughty head!

Strike! for the living and the martyr'd dead!

Strike! for the bones that fill your mothers' graves!

Strike! till your kindred are no longer slaves!

Strike! till fair Freedom on the world shall smile!

For G.o.d! for Truth! and FOR THE EMERALD ISLE!"

[Decoration]

[Decoration]

XIII.

_THE EARTH'S HOT CENTER._

The following extracts from the report of the Hon. John Flannagan, United States Consul at Bruges, in Belgium, to the Secretary of State, published in the Was.h.i.+ngton City _Telegraph_ of a late date, will fully explain what is meant by the "Great Scare in Belgium."

Our extracts are not taken continuously, as the entire doc.u.ment would be too voluminous for our pages. But where breaks appear we have indicated the hiatus in the usual manner by asterisks, or by brief explanations.

GEN. FLANNAGAN'S REPORT.

BRUGES, December 12, 1872.

To THE HON. HAMILTON FISH, Secretary of State.

SIR: In pursuance of special instructions recently received from Was.h.i.+ngton (containing inclosures from Prof. Henry of the Smithsonian Inst.i.tute, and Prof. Lovering of Harvard), I proceeded on Wednesday last to the scene of operations at the "International Exploring Works," and beg leave to submit the following circ.u.mstantial report:

Before proceeding to detail the actual state of affairs at Dudzeele, near the line of ca.n.a.l connecting Bruges with the North Sea, it may not be out of place to furnish a succinct history of the origin of the explorations out of which the present alarming events have arisen. It will be remembered by the State Department that during the short interregnum of the provisional government of France, under Lamartine and Cavaignac, in 1848, a proposition was submitted by France to the governments of the United States, Great Britain and Russia, and which was subsequently extended to King Leopold of Belgium, to create an "International Board for Subterranean Exploration" in furtherance of science, and in order, primarily, to test the truth of the theory of igneous central fusion, first propounded by Leibnitz, and afterward embraced by most of contemporary geologists; but also with the further objects of ascertaining the magnetic condition of the earth's crust, the variations of the needle at great depths, and finally to set at rest the doubts of some of the English mineralogists concerning the permanency of the coal measures, about which considerable alarm had been felt in all the manufacturing centers of Europe.

The protocol of a quintuple treaty was finally drawn by Prof.

Henry, of the Smithsonian Inst.i.tute, and approved by Sir Roderick Murchison, at that time President of the Royal Society of Great Britain. To this project Arago lent the weight of his great name, and Nesselrode affixed the approval of Russia, it being one of the last official acts performed by that veteran statesman.

The programme called for annual appropriations by each of the above-named powers of 100,000 francs (about $20,000 each), the appointment of commissioners and a general superintendent, the selection of a site for prosecuting the undertaking, and a board of scientific visitors, consisting of one member from each country.

It is unnecessary to detail the proceedings for the first few months after the organization of the commission. Prof. Watson, of Chicago, the author of a scientific treatise called "Prairie Geology," was selected by President Fillmore, as the first representative of the United States; Russia sent Olgokoff; France, Ango Jeuno; England, Sir Edward Sabine, the present President of the Royal Society; and Belgium, Dr. Secchi, since so famous for his spectroscopic observations on the fixed stars.

These gentlemen, after organizing at Paris, spent almost an entire year in traveling before a site for the scene of operations was selected. Finally, on the 10th of April, 1849, the first ground was broken for actual work at Dudzeele, in the neighborhood of Bruges, in the Kingdom of Belgium.

The considerations which led to the choice of this locality were the following: First, it was the most central, regarding the capitals of the parties to the protocol; secondly, it was easy of access and connected by rail with Brussels, Paris and St.

Petersburg, and by line of steamers with London, being situated within a short distance of the mouth of the Hond or west Scheldt; thirdly, and perhaps as the most important consideration of all, it was the seat of the deepest shaft in the world, namely, the old salt mine at Dudzeele, which had been worked from the time of the Romans down to the commencement of the present century, at which time it was abandoned, princ.i.p.ally on account of the intense heat at the bottom of the excavation, and which could not be entirely overcome except by the most costly scientific appliances.

There was still another reason, which, in the estimation of at least one member of the commission, Prof. Watson, overrode them all--the exceptional increase of heat with depth, which was its main characteristic.

The scientific facts upon which this great work was projected, may be stated as follows: It is the opinion of the princ.i.p.al modern geologists, based primarily upon the hypothesis of Kant (that the solar universe was originally an immense ma.s.s of incandescent vapor gradually cooled and hardened after being thrown off from the grand central body--afterward elaborated by La Place into the present nebular hypothesis)--that "the globe was once in a state of igneous fusion, and that as its heated ma.s.s began to cool, an exterior crust was formed, first very thin, and afterward gradually increasing until it attained its present thickness, which has been variously estimated at from ten to two hundred miles. During the process of gradual refrigeration, some portions of the crust cooled more rapidly than others, and the pressure on the interior igneous ma.s.s being unequal, the heated matter or lava burst through the thinner parts, and caused high-peaked mountains; the same cause also producing all volcanic action." The arguments in favor of this doctrine are almost innumerable; these are among the most prominent:

_First._ The form of the earth is just that which an igneous liquid ma.s.s would a.s.sume if thrown into an orbit with an axial revolution similar to that of our earth. Not many years ago Professor Faraday, a.s.sisted by Wheatstone, devised a most ingenious apparatus by which, in the laboratory of the Royal Society, he actually was enabled, by injecting a flame into a vacuum, to exhibit visibly all the phenomena of the formation of the solar universe, as contended for by La Place and by Humboldt in his "Cosmos."

_Secondly._ It is perfectly well ascertained that heat increases with depth, in all subterranean excavations. This is the invariable rule in mining shafts, and preventive measures must always be devised and used, by means generally of air apparatus, to temper the heat as the depth is augmented, else deep mining would have to be abandoned. The rate of increase has been variously estimated by different scientists in widely distant portions of the globe. A few of them may be mentioned at this place, since it was upon a total miscalculation on this head that led to the present most deplorable results.

The editor of the _Journal of Science_, in April, 1832, calculated from results obtained in six of the deepest coal mines in Durham and Northumberland, the mean rate of increase at one degree of Fahrenheit for a descent of forty-four English feet.

In this instance it is noticeable that the bulb of the thermometer was introduced into cavities purposely cut into the solid rock, at depths varying from two hundred to nine hundred feet. The Dolcoath mine in Cornwall, as examined by Mr. Fox, at the depth of thirteen hundred and eighty feet, gave on average result of four degrees for every seventy-five feet.

Kupffer compared results obtained from the silver mines in Mexico, Peru and Freiburg, from the salt wells of Saxony, and from the copper mines in the Caucasus, together with an examination of the tin mines of Cornwall and the coal mines in the north of England, and found the average to be at least one degree of Fahrenheit for every thirty-seven English feet.

Cordier, on the contrary, considers this amount somewhat overstated and reduces the general average to one degree Centigrade for every twenty-five metres, or about one degree of Fahrenheit for every forty-five feet English measure.

_Thirdly._ That the lavas taken from all parts of the world, when subjected to chemical a.n.a.lysis, 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 s.p.a.ce 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 s.h.i.+ft 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 princ.i.p.al 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 superinc.u.mbent 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 compa.s.s 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.

All electrical action also ceased, which fully confirms the theory, of Professor Faraday, that "electricity is a force generated by the rapid axial revolution of the earth, and that magnetic attraction in all cases points or operates at right angles to its current." Hence electricity, from the nature of its cause, must be superficial.

Every appearance of water disappeared at the depth of only 9000 feet. From this depth downward the rock was of a basaltic character, having not the slightest appearance of granite formation--confirming, in a most remarkable manner, the discovery made only last year, that all _granites_ are of _aqueous_, instead of _igneous_ deposition. As a corollary from the law of atmospheric pressure, it was found utterly impossible to vaporize water at a greater depth than 24,000 feet, which point was reached in 1869. No amount of heat affected it in the least perceptible manner, and on weighing the liquid at the greatest depth attained, by means of a nicely adjusted scale, it was found to be of a density expressed thus: 198,073, being two degrees or integers of atomic weight heavier than gold, at the surface.

The report then proceeds to discuss the question of the true figure of the earth, whether an oblate spheroid, as generally supposed, or only truncated at the poles; the length of a degree of longitude at the lat.i.tude of Dudzeele, 51 deg. 20 min. N., and one or two other problems.

The concluding portion of the report is reproduced in full.

For the past twelve months it was found impossible to endure the heat, even sheltered as the miners were by the atmospheric cover and cage, for more than fifteen minutes at a time, so that the expense of sinking had increased geometrically for the past two years. However, important results had been obtained, and a perpendicular depth reached many thousands of feet below the deepest sea soundings of Lieutenant Brooks. In fact, the enormous excavation, on the 1st of November, 1872, measured perpendicularly, no less than 37,810 feet and 6 inches from the floor of the shaft building! The highest peak of the Himalayas is only little over 28,000 feet, so that it can at once be seen that no time had been thrown away by the Commissioners since the inception of the undertaking, in April, 1849.

The first symptoms of alarm were felt on the evening of November 1. The men complained of a vast increase of heat, and the cages had to be dropped every five minutes for the greater part of the night; and of those who attempted to work, at least one half were extricated in a condition of fainting, but one degree from cyncope. Toward morning, hoa.r.s.e, profound and frequent subterranean explosions were heard, which had increased at noon to one dull, threatening and continuous roar. But the miners went down bravely to their tasks, and resolved to work as long as human endurance could bear it. But this was not to be much longer; for late at night, on the 4th, after hearing a terrible explosion, which shook the whole neighborhood, a hot sirocco issued from the bottom, which drove them all out in a state of asphyxia. The heat at the surface became absolutely unendurable, and on sending down a cage with only a dog in it, the materials of which it was composed took fire, and the animal perished in the flames. At 3 o'clock A. M. the iron fastenings to another cage were found fused, and the wire ropes were melted for more than 1000 feet at the other end. The detonations became more frequent, the trembling of the earth at the surface more violent, and the heat more oppressive around the mouth of the orifice. A few minutes before 4 o'clock a subterranean crash was heard, louder than Alpine thunder, and immediately afterward a furious cloud of ashes, smoke and gaseous exhalation shot high up into the still darkened atmosphere of night. At this time at least one thousand of the terrified and half-naked inhabitants of the neighboring village of Dudzeele had collected on the spot, and with wringing hands and fearful outcries bewailed their fate, and threatened instant death to the officers of the commission, and even to the now terrified miners. Finally, just before dawn, on the 5th of November, or, to be more precise, at exactly twenty minutes past 6 A. M., molten lava made its appearance at the surface!

The fright now became general, and as the burning buildings shed their ominous glare around, and the languid stream of liquid fire slowly bubbled up and rolled toward the ca.n.a.l, the scene a.s.sumed an aspect of awful sublimity and grandeur. The plains around were lit up for many leagues, and the foggy skies intensified and reduplicated the effects of the illumination. Toward sunrise the flow of lava was suspended for nearly an hour, but shortly after ten o'clock it suddenly increased its volume, and, as it cooled, formed a sort of saucer-shaped funnel, over the edges of which it boiled up, broke, and ran off in every direction. It was at this period that the accomplished Dusoloy, so long the Superintendent, lost his life. As the lava slowly meandered along, he attempted to cross the stream by stepping from one ma.s.s of surface cinders to another. Making a false step, the floating rock upon which he sprang suddenly turned over, and before relief could be afforded his body was consumed to a crisp. I regret to add that his fate kindled no sympathy among the a.s.sembled mult.i.tude; but they rudely seized his mutilated remains, and amid jeers, execrations, and shouts of triumph, attached a large stone to the half-consumed corpse and precipitated it into the ca.n.a.l. Thus are the heroes of science frequently sacrificed to the fury of a plebeian mob.