Part 6

If, as we have now seen, the very nature of a reflector demands certain conditions and the Moon does not manifest these conditions, it must of necessity be concluded that the Moon is _not_ a _reflector_, but a _self-luminous body_. If self-luminous her surface could not be darkened or eclipsed by a shadow of the Earth--supposing such were thrown upon it. The luminosity instead of being diminished would be greater in proportion to the greater density or darkness of the shadow. As the light in a lantern shines most brightly in the darkest places, so would the Moon’s self-luminous surface be most intense in the deepest part of the Earth’s shadow. It is thus rendered undeniable that a Lunar Eclipse _does_ not and _could_ not arise from a shadow of the Earth! As a _Solar_ Eclipse occurs from the Moon passing over the Sun; so from the evidence it is clear that a Lunar Eclipse _can only_ arise from a similar cause--a body semi-transparent and well-defined passing before the Moon, or between her surface and the observer on the surface of the Earth. That such a body exists is admitted by several distinguished astronomers. In the report of the Council of the Royal Astronomical Society for June, 1850, it is stated, “We may well doubt whether that body which we call the Moon is the _only satellite_ of the Earth.” In the report of the Academy of Sciences for October 12, 1846, and again for August, 1847, the Director of one of the French Observatories gives a number of observations and calculations which have led him to conclude that “there is at least _one non-luminous body_ of considerable magnitude which is attached as a _satellite to this Earth_.”[19]

[19] Referred to in Lardner’s “Museum of Science,” p. 159.

Persons who are unacquainted with the methods of calculating Eclipses and other astronomical phenomena, are prone to look upon the correctness of these calculations as powerful arguments in favour of the doctrine of the Earth’s rotundity and the Newtonian philosophy generally. But this is erroneous. Whatever theory is adopted, or if all theories are discarded, the same results may follow, because the necessary data may be tabulated and employed independently of all theory, or may be mixed up with any, even the most opposite doctrines, or kept distinct from every system, just as the operator may decide. The tables of the Moon’s relative positions for almost any second of time are purely practical, the result of long continued observation, and may or may not be mixed up with hypothesis. In Smith’s “Rise and progress of Astronomy,” speaking of Ptolemy, who lived in the 2nd century of the Christian Era, it is said, “The (considered) defects of his system did not prevent him from calculating all the Eclipses that were to happen for 600 years to come.” Professor Partington, at page 370 of his Lectures on Natural Philosophy, says, “The most ancient observations of which we are in possession, that are sufficiently accurate to be employed in astronomical calculations, are those made at Babylon about 719 before the Christian Era, of three Eclipses of the Moon. Ptolemy, who has transmitted them to us, employed them for determining the period of the Moon’s mean motion; and therefore had probably none more ancient on which he could depend. The Chaldeans, however, must have made a long series of observations before they could discover their “Saros” or lunar period of 6,585¹⁄₃ days, or about 18 years; at which time, as they had learnt, the place of the Moon, her _node_ and _apogee_ return nearly to the same situation with respect to the Earth and the Sun, and, of course, a series of nearly similar Eclipses occur.”

Sir Richard Phillips, in his “Million of Facts,” at page 388, says:--“The precision of astronomy arises, not from theories, but from prolonged observations, and the regularity of the motions, or the ascertained uniformity of their irregularities. Ephemerides of the planets’ places, of Eclipses, &c., have been published for above 300 years, and were nearly as precise as at present.”

“No particular theory is required to calculate Eclipses; and the calculations may be made with equal accuracy _independent of every theory_.”[20]

[20] Somerville’s Physical Sciences, p. 46.

SECTION 10.

CAUSE OF TIDES.

The doctrine of the Earth’s rotundity being fallacious, all ideas of “centre of attraction of gravitation,” “mutual attraction of Earth and Moon,” &c., &c., must be given up; and the cause of tides in the ocean must be sought for in another direction. It is certain that there is a constant pressure of the atmosphere upon the surface of the Earth and ocean. This is proved by ordinary barometrical observations, many Pneumatic experiments, and by the fact that during the most fearful storms at sea the surface only is disturbed; at the depth of a hundred feet the water is always calm--except in the path of well-marked currents and local submarine phenomena. The following quotations gathered from casual reading fully corroborate this statement. “It is amazing how superficial is the most terrible tempest. Divers assure us that in the greatest storms calm water is found at the depth of 90 feet.”[21]

[21] Chambers’s Journal, No. 100, p. 379.

“This motion of the surface of the sea is not perceptible to a great depth. In the strongest gale it is supposed not to extend beyond 72 feet below the surface; and at the depth of 90 feet the sea is perfectly still.”[22]

[22] Penny Cyclopædia, Article Sea.

“The people are under a great mistake who believe that the substance of the water moves to any considerable depth in a storm at sea. It is only the form or shadow which hurries along like a spirit, or like a thought over the countenance of the ‘great deep,’ at the rate of some forty miles an hour. Even when the ‘Flying Dutchman’ is abroad the great mass of water continues undisturbed and nearly motionless a few feet below the surface.”[23]

[23] London Saturday Journal, August 8, 1840, p. 71.

“The unabraded appearance of the shells brought up from great depths, and the almost total absence of the mixture of any _detritus_ from the sea, or foreign matter, suggest most forcibly the idea of _perfect repose_ at the bottom of the deep sea.”[24]

[24] Physical Geography of the Sea, by Lieut. Maury, p. 265.

Bearing this fact in mind, that there exists a continual pressure of the atmosphere upon the Earth, and associating it with the fact that the Earth is a vast plane “stretched out upon the waters,” and it will be seen that it must of necessity slightly fluctuate, or slowly rise and fall in the water. As by the action of the atmosphere the Earth is slowly depressed, the water moves towards the receding shores and produces the flood tide; and when by the reaction of the resisting oceanic medium the Earth gradually ascends the waters recede, and the ebb tide is produced. This is the _general_ cause of tides. Whatever peculiarities are observable they may be traced to the reaction of channels, bays, headlands, and other local causes.

If a raft, or a ship, or any other structure floating upon water be carefully observed, it will be seen to have a gentle fluctuating motion. However calm the water and the atmosphere may be, this gradual rising and falling of the floating mass is always more or less observable. If vessels of different sizes are floating near each other they will be seen to fluctuate with different velocities, the largest and heaviest will move the least rapidly. This motion will be observable whether the vessels be held by their anchors, or moored to buoys, or freely floating in still water. A large and heavily laden vessel will make several fluctuations in a minute of time; the Earth once only in about twelve hours, because it is proportionately larger.

To this simple condition of the Earth,--the action or pressure upon it of the atmosphere, and the reaction or resistance to it of the water, may be traced all the leading peculiarities of the tides. The simultaneous ebb and flow upon meridians 180° apart. The absence of high and low water in large inland seas and lakes; which being contained within and fluctuating with the Earth cannot therefore show a relative change in the altitude of the surface. The flux and reflux observed in several inland wells and basins though far from the sea, but being connected with it by subterranean passages, necessarily show a relative difference in the surface levels of the earth and water. And the regular ebb and flood of the water in the great Polar sea recently discovered by Dr. Kane, although it is separated from the great tidal current of the Atlantic Ocean by deep barriers of ice--as will be seen by the following quotation:--“Dr. Kane reported an open sea north of the parallel of 82°. To reach it his party crossed a barrier of ice 80 or 100 miles broad. Before gaining this open water he found the thermometer to show the extreme temperature of -60°. Passing this ice-bound region by travelling North, he stood on the shores of an iceless sea extending in an unbroken sheet of water as far as the eye could reach towards the pole. Its waves were dashing on the beach with the swell of a boundless ocean. The tides ebbed and flowed in it, and I apprehend that the tidal wave from the Atlantic can no more pass under this icy barrier to be propagated in seas beyond than the vibrations of a musical string can pass with its notes a ‘fret’ upon which the musician has placed his finger. * * * These tides therefore must have been born in that cold sea, having their cradle about the North Pole; and we infer that most, if not all, the unexplored regions about the Pole are covered with deep water; for, were this unexpected area mostly land, or shallow water, it could not give birth to regular tides.”[25]

[25] Physical Geography of the Sea, by Lieut. Maury, p. 176.

That the Earth has a vibratory or tremulous motion, such as must necessarily belong to a floating and fluctuating structure, is abundantly proved by the experience of astronomers and surveyors. If a delicate spirit-level be firmly placed upon a rock or upon the most solid foundation which it is possible to construct, the very curious phenomenon will be observed of constant change in the position of the air-bubble. However carefully the “level” may be adjusted, and the instrument protected from the atmosphere, the “bubble” will not maintain its position many seconds together. A somewhat similar influence has been noticed in astronomical observatories, where instruments of the best construction and placed in the most approved positions cannot always be relied upon without occasional re-adjustment.

SECTION 11.

CONSTITUTION, CONDITION, AND ULTIMATE DESTRUCTION OF THE EARTH BY FIRE.

Chemical analysis proves to us the important fact that the great bulk of the Earth--meaning thereby the _land_ as distinct from the waters--is composed of metallic oxides or metals in combination with oxygen. When means are adopted to remove the oxygen it is found that most of these metallic bases are highly combustible. The different degrees of affinity existing among the elements of the Earth, give rise to all the rocks, minerals, ores, deposits, and strata which constitute the material habitable world. The different specific gravities or relative densities which these substances are found to possess, and the numerous evidences which exist of their former plastic or semi-fluid condition, afford positive proof that from a once commingled or chaotic state regular but rapid precipitation, stratification, crystallization, and concretion successively occurred; and that in some way not yet clear to us sufficient chemical action was produced to ignite a great portion of the Earth, and to reduce it to a molten incandescent state, the volatile products of which being forcibly eliminated have broken up the stratified formations, and produced the irregular confused condition which we now observe. That such an incandescent molten state of a great portion of the lower parts of the Earth still exists is a matter of certainty; and there is evidence that the heat thus internally generated is gradually increasing.

“The uppermost strata of the soil share in all the variations of temperature which depend upon the seasons; and this influence is exerted to a depth which, although it varies with the latitude, is never very great. Beyond this point the temperature rises in proportion as we descend to greater depths, and it has been shown, by numerous and often-repeated experiments, that the increase of temperature is on average one degree (Fahrenheit) for about every 545 feet. Hence it results that at a depth of about twelve miles from the surface, we should be on the verge of an incandescent mass.”[26]

[26] Rambles of a Naturalist, by M. de Quatrefages.

“So great is the heat within the Earth, that in Switzerland, and other countries where the springs of water are very deep, they bring to the surface the warm mineral waters so much used for baths and medicine for the sick; and it is said, that if you were to dig very deep down into the Earth, the temperature would increase at the rate of one degree of the thermometer for every 100 feet; so that, at the depth of 7000 feet, or one mile and a half, all the water that you found would be boiling; and at the depth of about ten miles all the rocks would be melted. * * * A day will yet come when this earth will be burned up by the fire. There is fire, as you have heard, within it, ready to burst forth at any moment.”[27] “This earth, although covered all round with a solid crust, is all on fire within. Its interior is supposed to be a burning mass of melted, glowing metals, fiery gas, and boiling lava. * * * * * The solid crust which covers this inward fire is supposed not to be much more than from 9 to 12 miles in thickness. Whenever this crust breaks open, or is cleft in any place, there rush out lava, fire, melted rocks, fiery gases, and ashes, sometimes in such floods as to bury whole cities. From time to time we read of the earth quaking, trembling, and sometimes opening, and of mountains and small islands (which are mountains in the sea) being thrown up in a day.”[28]

[27] “The World’s Birthday,” by Professor Gaussen, Geneva, p. 43.

[28] “The World’s Birthday,” by Professor Gaussen, Geneva, p. 42.

In a periodical called “Recreative Science,” at the end of an interesting article on volcanoes, &c., the following sentence occurs:--“The conclusion is therefore inevitable, that the general distribution all over the earth of volcanic vents, their similarity of action and products, their enormous power and seeming inexhaustibility, their extensiveness of action in their respective sites, the continuance of their energies during countless years, and the incessant burning day and night, from year to year, of such craters as Stromboli; and lastly, the apparent inefficiency of external circumstances in controlling their operations, eruptions happening beneath the sea as beneath the land, in the frigid as in the torrid zone, for these and many less striking phenomena, we must seek for some great and general cause, such only as the central heat of the earth affords us.”

Sir Richard Phillips says, “at the depth of 50 feet (from the sea level) the temperature of the earth is the same winter and summer.” * * * “The deepest coal mine in England is at Killingworth, near Newcastle-upon-Tyne, and the mean annual temperature at 400 yards below the surface is 77°; and at 300 yards, 70°; while at the surface it is but 48°, being about one degree of increase for every 15 yards. Hence, at 3,300 yards, the heat would be equal to boiling water, taking 20 yards to a degree. This explains the origin of hot springs. The heat of the Bath waters is 116°, hence they would appear to rise from a depth of 1,320 yards. By experiments made at the Observatory of Paris for ascertaining the increase of temperature from the surface of the earth towards the interior, 51 feet, or 17 yards, corresponds to the increase of one degree Fahrenheit’s thermometer. Hence, the temperature of boiling water would be at 8,212 feet, or about 1¹⁄₂ English miles under Paris.”

Professor Silliman, of America, states “that in boring the Artesian wells in Paris, the temperature increased at the rate of 1 degree for every 50 feet downwards; and, reasoning from causes known to exist, the whole of the interior part of the earth, or, at least, a great part of it, is an ocean of melted rock agitated by violent winds.”

Sir Charles Lyell, in his address to the British Association, assembled at Bath, September, 1864, speaking of hot springs generally, said “An increase of heat is always experienced as we descend into the interior of the earth. * * * The estimate deduced by Mr. Hopkins, from an accurate series of observations made in the Monkwearmouth shaft, near Durham, and in the Dukenfield shaft, near Manchester, each of them 2,000 feet in depth. In these shafts the temperature was found to rise at the rate of 1° Fah. for every increase of depth of from 65 to 70 feet.”

“The observations made by M. Arago, in 1821, that the deepest Artesian wells are the warmest, threw great light on the origin of thermal springs, and on the establishment of the law, that terrestrial heat increases with increasing depth. It is a remarkable fact, which has but recently been noticed, that at the close of the third century St Patricius, probably Bishop of Partusa, was led to adopt very correct views regarding the phenomenon of the hot springs at Carthage. On being asked what was the cause of boiling water bursting from the earth, he replied, ‘Fire is nourished in the clouds, and in the interior of the earth, as Etna and other mountains near Naples may teach you. The subterranean waters rise as if through siphons. The cause of hot springs is this: waters which are more remote from the subterranean fire are colder, whilst those which rise nearer the fire, are heated by it, and bring with them to the surface which we inhabit, an insupportable degree of heat.’”[29]

[29] “Humboldt’s Cosmos,” p. 220.

The investigations which have been made, and the evidence which has been brought together, render it undeniable that the lower parts of the earth are on fire. Of the intensity of the combustion, no practical idea can be formed. It is fearful beyond comparison. The lava thrown out from a volcano in Mexico, “was so hot that it continued to smoke for twenty years; and after three years and a half, a piece of wood took fire in it, at a distance of five miles from the crater.” In various parts of the world, large islands have been thrown up from the sea, in a red-hot glowing condition, and so intensely heated, that after being forced through many fathoms of salt water, and standing in the midst of it, exposed to wind and rain for several months, they were not sufficiently cooled for persons to approach and stand upon them. “A notable fact is the force exerted in volcanic action, Cotopaxi, in 1738, threw its fiery rockets 3,000 feet above its crater, while in 1744 the blazing mass, struggling for an outlet, roared like a furnace, so that its awful voice was heard at a distance of more than six hundred miles. In 1797, the crater of Tunguragua, one of the great peaks of the Andes, flung out torrents of mud, which dammed up rivers, opened new lakes, and in valleys of a thousand feet wide made deposits six hundred feet deep. The stream from Vesuvius which, in 1737, passed through Torre del Greco, contained thirty-three million cubic feet of solid matter; and, in 1794, when Torre del Greco was destroyed a second time, the mass of lava amounted to forty-five million cubic feet. In 1669 Etna poured forth a flood which covered 84 square miles of surface, and measured nearly 100,000,000 cubic feet. On this occasion the sand and scoriæ formed the Monte Rossi, near Nicolosi, a cone two miles in circumference, and four hundred and fifty feet high. The stream thrown out by Etna, in 1819, was in motion, at the rate of a yard per day, for nine months after the eruption; and it is on record that the lavas of the same mountain, after a terrible eruption, were not thoroughly cooled and consolidated ten years after the event. In the eruption of Vesuvius, A.D. 79, the scoriæ and ashes vomited forth far exceeded the entire bulk of the mountain; while, in 1660, Etna disgorged more than twenty times its own mass. * * * Vesuvius has thrown its ashes as far as Constantinople, Syria, and Egypt; it hurled stones eight pounds in weight to Pompeii, a distance of six miles; while similar masses were tossed up 2,000 feet above its summit. Cotopaxi has projected a block one hundred cubic yards in volume a distance of nine miles, while Sumbawa, in 1815, during the most terrible eruption on record, sent its ashes as far as Java, a distance of three hundred miles. * * * In viewing these evidences of enormous power, we are forcibly struck with the similarity of action with which they have been associated; and, carrying our investigation a step further, the same similarity of the producing power is hinted at in the identity of the materials ejected. Thus, if we classify the characteristics of all recorded eruptions, we shall find that the phenomena are all reducible to upheavals of the earth, rumblings and explosions, ejections of carbonic acid, fiery torrents of lava, cinders, and mud, with accompanying thunder and lightning. The last-named phenomena are extrajudicial in character; they are merely the result of the atmospheric disturbance consequent on the escape of great heat from the earth, just as the burning of an American forest causes thunder and rain. The connection that apparently exists, too, between neighbouring craters is strongly confirmed by the fact that in every distinct volcanic locus but _one_ crater is usually active at a time. Since Vesuvius has resumed his activity, the numerous volcanic vents on the other side of the bay have sunk into comparative inactivity; for ancient writers, who are silent respecting the former, speak of the mephitic vapours of the Lake Avernus as destructive to animal existence, and in earlier days than these Homer pictures the Phlegrean Fields as the entrance to the infernal regions, placed at the limits of the habitable world, unenlightened by rising or setting sun, and enveloped in eternal gloom. * * * * The earth contains within it a mass of heated material; nay, it is a heated and incandescent body, habitable only because surrounded with a cool crust--the crust being to it a mere shell, within which the vast internal fires are securely inclosed: and yet not securely, perhaps, unless such vents existed as those to which we apply the term volcano. * * * * Every volcano is a safety-valve, ready to relieve the pressure from within when that pressure rises to a certain degree of intensity; or permanently serving for the escape of conflagrations, which, if not so provided with escape, might rend the habitable crust to pieces.”[30]

[30] Recreative Science, p.p. 257 to 260.

Thus it is certain, from the phenomena of earthquakes, submarine and inland volcanoes which exist in every part of the earth from the frozen to the tropical regions, hot and boiling springs, fountains of mud and steam, lakes of burning sulphur, jets and blasts of destructive gases, and the choke and fire damps of our coal mines, that at a few miles only below the surface of the earth there exists a vast region of combustion, the intensity and power of which are indescribable, and cannot be compared with anything within the range of human experience.