Ragnarok : the Age of Fire and Gravel. Ignatius Donnelly

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СКАЧАТЬ or none. Therefore clays which are derived from feldspar are light-colored or white, while those partially made up of decomposed mica or hornblende are dark, either bluish or red."[1]

      The tail of the comet seems to be perpetually in motion. It is, says one writer, "continually changing and fluctuating as vaporous masses of cloud-like structure might be conceived to do, and in some instances there has been a strong appearance even of an undulating movement."[2]

      The great comet of 1858, Donati's comet, which many now living will well remember, and which was of such size that when its head was near our horizon the extremity of the tail reached nearly to the zenith, illustrated this continual movement of the material of the tail; that appendage shrank and enlarged millions of miles in length.

      Mr. Lockyer believed that he saw in Coggia's comet the evidences of a whirling motion--

      "In which the regions of greatest brightness were caused by the different coils cutting, or appearing to cut, each other, and so in these parts leading to compression or condensation, and frequent collision of the luminous particles."

      Olbers saw in a comet's tail--

      "A sudden flash and pulsation of light which vibrated for several seconds through it, and the tail appeared during the continuance of the pulsations of light to be lengthened by several degrees and then again contracted."[1]

      [1. "American Cyclopædia," article "Clay."

      2. "Edinburgh Review," October, 1874, p. 208,

      3, "Cosmos," vol. i, p. 143.]

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      Now, in this perpetual motion, this conflict, these great thrills of movement, we are to find the source of the clays which cover a large part of our globe to a depth of hundreds of feet. Where are those exposures of granite on the face of the earth from which ice or water could have ground them? Granite, I repeat, comes to the surface only in limited areas. And it must be remembered that clay is the product exclusively of granite ground to powder. The clays are composed exclusively of the products of disintegrated granite. They contain but a trace of lime or magnesia or organic matters, and these can be supposed to have been infiltrated into them after their arrival on the face of the earth.[1] Other kinds of rock, ground up, form sand. Moreover, we have seen that neither glaciers nor ice-sheets now produce such clays.

      We shall see, as we proceed, that the legends of mankind, in describing the comet that struck the earth, represent it as party-colored; it is "speckled" in one legend; spotted like a tiger in another; sometimes it is a white boar in the heavens; sometimes a blue snake; sometimes it is red with the blood of the millions that are to perish. Doubtless these separate formations, ground out of the granite, from the mica, hornblende, or feldspar, respectively, may, as I have said, under great laws, acted upon by magnetism or electricity, have arranged themselves in separate lines or sheets, in the tail of the comet, and hence we find that the clays of one region are of one color, while those of another are of a different hue. Again, we shall see that the legends represent the monster as "winding," undulating, writhing, twisting, fold over fold, precisely as the telescopes show us the comets do to-day.

      [1. "American Cyclopædia," vol. iv, p. 650.]

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      The very fact that these waves of motion run through the tail of the comet, and that it is capable of expanding and contracting on an immense scale, is conclusive proof that it is composed of small, adjustable particles. The writer from whom I have already quoted, speaking of the extraordinary comet of 1843, says:

      "As the comet moves past the great luminary, it sweeps round its tail as a sword may be conceived to be held out at arm's-length, and then waved round the head, from one side to the opposite. But a sword with a blade one hundred and fifty millions of miles long must be a somewhat awkward weapon to brandish round after this fashion. Its point would have to sweep through a curve stretching out more than six hundred millions of miles; and, even with an allowance of two hours for the accomplishment of the movement, the flash of the weapon would be of such terrific velocity that it is not an easy task to conceive how any blade of connected material substance could bear the strain of the stroke. Even with a blade that possessed the coherence and tenacity of iron or steel, the case would be one that it would be difficult for molecular cohesion to deal with. But that difficulty is almost infinitely increased when it is a substance of much lower cohesive tenacity than either iron or steel that has to be subjected to the strain.

      "There would be, at least, some mitigation of this difficulty if it were lawful to assume that the substance which is subjected to this strain was not amenable to the laws of ponderable existence; if there were room for the notion that comets and their tails, which have to be brandished in such a stupendous fashion, were sky-spectres, immaterial phantoms, unreal visions of that negative shadow-kind which has been alluded to. This, however, unfortunately, is not a permissible alternative in the circumstances of the case. The great underlying and indispensable fact that the comet comes rushing up toward the sun out of space, and then shoots round that great center of attraction by the force of its own acquired and ever-increasing impetuosity; the fact that it is obedient

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      through this course to the law of elliptical, or, to speak more exactly, of conic-section, movement, permits of no doubt as to the condition of materiality. The comet is obviously drawn by the influence of the sun's mass, and is subservient to that all-pervading law of sympathetic gravitation that is the sustaining bond of the material universe. It is ponderable substance beyond all question, and held by that chain of physical connection which it was the glory of Newton to discover. If the comet were not a material and ponderable substance it would not gravitate round the sun, and it would not move with increasing velocity as it neared the mighty mass until it had gathered the energy for its own escape in the enhanced and quickened momentum. In the first instance, the ready obedience to the attraction, and then the overshooting of the spot from which it is exerted, combine to establish the comet's right to stand ranked at least among the ponderable bodies of space."[1]

      And it is to the comet we must look for the source of a great part of those vast deposits of gravel which go to constitute the Drift.

      "They have been usually attributed to the action of waves; but the mechanical work of the ocean is mostly confined to its shores and soundings, where alone material exists in quantity within reach of the waves and currents.[2] … The eroding action is greatest for a short distance above the height of half-tide, and, except in violent storms, it is almost null below low-tide."[3]

      But if any one will examine a sea-beach he will see, not a vast mass of pebbles perpetually rolling and grinding each other, but an expanse of sand. And this is to be expected; for as soon as a part of the pebbles is, by the attrition of the waves, reduced to sand, the sand packs around the stones and arrests their further waste. To form such a mass of gravel as is found in the Drift we

      [1. "Edinburgh Review," October, 1874, p. 202.

      2. Dana's "Text Book," p. 286.

      3. Ibid., p. 287.]

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      must conceive of some way whereby, as soon as the sand is formed, it is removed from the stones while the work of attrition goes on. This process we can conceive of in a comet, if the finer detritus is constantly carried back and arranged in the order of the size of its particles.

      To illustrate my meaning: let one place any hard substance, consisting of large fragments, in a mortar, and proceed to reduce it with a pestle СКАЧАТЬ