by W. H. Rhodes
[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 Washington City _Telegraph_ of a late date, will fullyexplain what is meant by the "Great Scare in Belgium."
Our extracts are not taken continuously, as the entire document would betoo voluminous for our pages. But where breaks appear we have indicatedthe 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 Washington (containing inclosures from Prof. Henry of the Smithsonian Institute, 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 circumstantial report:
Before proceeding to detail the actual state of affairs at Dudzeele, near the line of canal 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 Institute, 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, principally 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 principal modern geologists, based primarily upon the hypothesis of Kant (that the solar universe was originally an immense mass 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 mass 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 mass 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 mass would assume if thrown into an orbit with an axial revolution similar to that of our earth. Not many years ago Professor Faraday, assisted 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 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 successfulcontrivance for forcing air into the shaft at the greatest depths, onlya 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.
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 ofthe earth, whether an oblate spheroid, as generally supposed, or onlytruncated at the poles; the length of a degree of longitude at thelatitude 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, hoarse, 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 canal, the scene assumed 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 mass 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 assembled multitude; 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 canal. Thus are the heroes of science frequently sacrificed to the fury of a plebeian mob.
It would afford me a pleasure to inform the department that the unforeseen evils of our scientific convention terminated here. But I regret to add that such is very far from being the case. Indeed, from the appearance of affairs this morning at the volcanic crater--for such it has now become--the possible evils are almost incalculable. The Belgian Government was duly notified by telegraph of the death of the Superintendent and the mutinous disposition of the common people about Bruges, and early on the morning of the 6th of November a squad of flying horse was dispatched to the spot to maintain order. But this interference only made matters worse. The discontent, augmented by the wildest panic, became universal, and the mob reigned supreme. Nor could the poor wretches be greatly condemned; for toward evening the lava current reached the confines of the old village of Dudzeele, and about midnight set the town on fire. The lurid glare of the conflagration awakened the old burghers of Bruges from their slumbers and spread consternation in the city, though distant several miles from the spot. A meeting was called at the Guildhall at dawn, and the wildest excitement prevailed. But after hearing explanations from the members of the commission, the populace quietly but doggedly dispersed. The government from this time forward did all that power and prudence combined could effect to quell the reign of terror around Bruges. In this country the telegraph, being a government monopoly, has been rigorously watched and a cordon of military posts established around the threatened district, so that it has been almost impossible to convey intelligence of this disaster beyond the limits of the danger. In the mean time, a congress of the most experienced scientists was invited to the scene for the purpose of suggesting some remedy against the prospective spread of the devastation. The first meeting took place at the old Guildhall in Bruges and was strictly private, none being admitted except the diplomatic representatives of foreign governments, and the members elect of the college. As in duty bound, I felt called on to attend, and shall in this place attempt a short synopsis of the proceedings.
Professor Palmieri, of Naples, presided, and Dr. Kirchoff officiated as secretary.
Gassiot, of Paris, was the first speaker, and contended that the theory of nucleatic fusion, now being fully established it only remained to prescribe the laws governing its superficial action. "There is but one law applicable, that I am aware of," said he, "and that is the law which drives from the center of a revolving body all fluid matter toward the circumference, and forcibly ejects it into space, if possible, in the same manner that a common grindstone in rapid motion will drive off from its rim drops of water or other foreign unattached matter. Thus, whenever we find a vent or open orifice, as in the craters of active volcanoes, the incandescent lava boils up and frequently overflows the top of the highest peak of the Andes."
Palmieri then asked the speaker "if he wished to be understood as expressing the unqualified opinion that an orifice once being opened would continue to flow forever, and that there was no law governing the quantity or regulating the level to which it could rise?"
Gassiot replied in the affirmative.
The Neapolitan philosopher then added: "I dissent _in toto_ from the opinion of M. Gassiot. For more than a quarter of a century I have studied the lava-flows of Vesuvius, AEtna and Stromboli, and I can assure the Congress that the Creator has left no such flaw in His mechanism of the globe. The truth is, that molten lava can only rise about 21,000 feet above the level of the sea, owing to the balance-wheel of terrestrial gravitation, which counteracts at that height all centrifugal energy. Were this not so, the entire contents of the globe would gush from the incandescent center and fly off into surrounding space."
M. Gassiot replied, "that true volcanoes were supplied by nature with _circumvalvular lips_, and hence, after filling their craters, they ceased to flow. But in the instance before us no such provision existed, and the only protection which he could conceive of consisted in the smallness of the orifice; and he would therefore recommend his Majesty King Leopold to direct all his efforts to confine the aperture to its present size."
Palmieri again responded, "that he had no doubt but that the crater at
Dudzeele would continue to flow until it had built up around itself basaltic walls to the height of many hundreds, perhaps thousands, of feet, and that the idea of setting bounds to the size of the mouth of the excavation was simply ridiculous."
Gassiot interrupted, and was about to answer in a very excited tone, when Prof. Palmieri "disclaimed any intention of personal insult, but spoke from a scientific standpoint." He then proceeded: "The lava bed of Mount AEtna maintains a normal level of 7000 feet, while Vesuvius calmly reposes at a little more than one half that altitude. On the other hand, according to Prof. Whitney, of the Pacific Survey, Mount Kilauea, in the Sandwich Islands, bubbles up to the enormous height of 17,000 feet. It cannot be contended that the crater of Vesuvius is not a true nucleatic orifice, because I have demonstrated that the molten bed regularly rises and falls like the tides of the ocean when controlled by the moon." It was seen at once that the scientists present were totally unprepared to discuss the question in its novel and most important aspects; and on taking a vote, at the close of the session, the members were equally divided between the opinions of Gassiot and Palmieri. A further session will take place on the arrival of Prof. Tyndall, who has been telegraphed for from New York, and of the great Russian geologist and astronomer, Tugenieff.
In conclusion, the damage already done may be summed up as follows: The destruction of the Bruges and Hond Canal by the formation of a basaltic dyke across it more than two hundred feet wide, the burning of Dudzeele, and the devastation of about thirty thousand acres of valuable land. At the same time it is utterly impossible to predict where the damage may stop, inasmuch as early this morning the mouth of the crater had fallen in, and the flowing stream had more than doubled in size.
In consideration of the part hitherto taken by the Government of the United States in originating the work that led to the catastrophe, and by request of M. Musenheim, the Belgian Foreign Secretary, I have taken the liberty of drawing upon the State Department for eighty-seven thousand dollars, being the sum agreed to be paid for the cost of emigration to the United States of two hundred families (our own pro rata) rendered homeless by the conflagration of Dudzeele.
I am this moment in receipt of your telegram dated yesterday, and rejoice to learn that Prof. Agassiz has returned from the South Seas, and will be sent forward without delay.
With great respect, I have the honor to be your obedient servant,
JOHN FLANNAGAN, United States Consul at Bruges.
P.S.--Since concluding the above dispatch, Professor Palmieri did me the honor of a special call, and, after some desultory conversation, approached the all-absorbing topic of the day, and cautiously expressed his opinion as follows: Explaining his theory, as announced at the Congress, he said that "Holland, Belgium, and Denmark, being all low countries, some portions of each lying below the sea-level, he would not be surprised if the present outflow of lava devastated them all, and covered the bottom of the North Sea for many square leagues with a bed of basalt." The reason given was this: "That lava must continue to flow until, by its own action, it builds up around the volcanic crater a rim or cone high enough to afford a counterpoise to the centrifugal tendency of axial energy; and that, as the earth's crust was demonstrated to be exceptionally thin in the north of Europe, the height required in this instance would be so great that an enormous lapse of time must ensue before the self-created cone could obtain the necessary altitude. Before _AEtna_ attained its present secure height, it devastated an area as large as France; and Prof. Whitney has demonstrated that some center of volcanic action, now extinct, in the State of California, threw out a stream that covered a much greater surface, as the basaltic table mountains, vulgarly so called, extend north and south for a distance as great as from Moscow to Rome." In concluding his remarks, he ventured the prediction that "the North Sea would be completely filled up, and the British Islands again connected with the Continent."
J. F., U.S.C.