Chapter 31

A LESSON ON VOLCANOES.--PRIMARY COLORS ARE CAPABLE OF FARTHER SUBDIVISION.

“Get into the boat,” said my eyeless pilot, “and we will proceed to the farther edge of the lake, over the barrier of which at great intervals of time, the surface water flows, and induces the convulsion known as Mount Epomeo.”

We accordingly embarked, and a gentle touch of the lever enabled us rapidly to skirt the shore of the underground sea. The soft, bright, pleasant earth-light continually enveloped us, and the absence of either excessive heat or cold, rendered existence delightful. The weird forms taken by the objects that successively presented themselves on the shore were a source of continual delight to my mind. The motion of our boat was constantly at the will of my guide. Now we would skim across a great bay, flashing from point to point; again we wound slowly through tortuous channels and among partly submerged stones.

“What a blessing this mode of locomotion would be to humanity,” I murmured.

“Humanity will yet attain it,” he replied. “Step by step men have stumbled along towards the goal that the light of coming centuries is destined to illuminate. They have studied, and are still engaged in studying, the properties of grosser forces, such as heat and electricity, and they will be led by the thread they are following, to this and other achievements yet unthought of, but which lie back of those more conspicuous.”

[Illustration: “WE FINALLY REACHED A PRECIPITOUS BLUFF.”]

We finally reached a precipitous bluff, that sprung to my view as by magic, and which, with a glass-like surface, stretched upward to a height beyond the scope of my vision, rising straight from the surface of the lake. It was composed of a material seemingly black as jet, and yet when seen under varying spectacular conditions as we skirted its base it reflected, or emitted, most gorgeously the brilliant hues of the rainbow, and also other colors hitherto unknown to me.

“There is something unique in these shades; species of color appear that I can not identify; I seem to perceive colors utterly unlike any that I know as the result of deflected, or transmitted, sunlight rays, and they look unlike the combinations of primary colors with which I am familiar.”

“Your observations are true; some of these colors are unknown on earth.”

“But on the surface of the earth we have all possible combinations of the seven prismatic rays,” I answered. “How can there be others here?”

“Because, first, your primary colors are capable of further subdivision.

“Second, other rays, invisible to men under usual conditions, also emanate from the sun, and under favorable circumstances may be brought to the sense of sight.”

“Do you assert that the prism is capable of only partly analyzing the sunlight?”

“Yes; what reason have you to argue that, because a triangular bit of glass resolves a white ray into seven fractions that are, as men say, differently colored, you could not by proper methods subdivide each of these so-called primary shades into others? What reason have you to doubt that rays now invisible to man accompany those capable of impressing his senses, and might by proper methods become perceptible as new colors?”

“None,” I answered; “only that I have no proof that such rays exist.”

“But they do exist, and men will yet learn that the term ‘primitive’ ray, as applied to each of the seven colors of the rainbow, is incorrect. Each will yet be resolved, and as our faculties multiply and become more subtle, other colors will be developed, possessed of a delicacy and richness indescribable now, for as yet man can not comprehend the possibilities of education beyond the limits of his present condition.”

During this period of conversation we skirted the richly colored bluff with a rapid motion, and at last shot beyond it, as with a flash, into seeming vacancy. I was sitting with my gaze directed toward the bluff, and when it instantly disappeared, I rubbed my eyes to convince myself of their truthfulness, and as I did so our boat came gradually to a stand on the edge of what appeared to be an unfathomable abyss. Beneath me on the side where had risen the bluff that disappeared so abruptly, as far as the eye could reach, was an absolute void. To our right, and before and behind us, stretched the surface of that great smooth lake on whose bosom we rested. To our left, our boat brushing its rim, a narrow ledge, a continuation of the black, glass-like material, reached only a foot above the water, and beyond this narrow brink the mass descended perpendicularly to seemingly infinite depths. Involuntarily I grasped the sides of the boat, and recoiled from the frightful chasm, over which I had been so suddenly suspended, and which exceeded anything of a similar description that I had ever seen. The immeasurable depth of the abyss, in connection with the apparently frail barrier that held the great lake in its bounds, caused me to shudder and shrink back, and my brain reeled in dizzy fright. An inexplicable attraction, however, notwithstanding my dread, held me spell-bound, and although I struggled to shut out that view, the endeavor failed. I seemed to be drawn by an irresistible power, and yet I shuddered at the awful majesty of that yawning gulf which threatened to end the world on which I then existed. Fascinated, entranced, I could not help gazing, I knew not how long, down, down into that fathomless, silent profundity. Composing myself, I turned a questioning glance on my guide.

He informed me that this hard, glass-like dam confined the waters of the slowly rising lake that we were sailing over, and which finally would rise high enough to overflow the barrier.

[Illustration: “THE WALL DESCENDED PERPENDICULARLY TO SEEMINGLY INFINITE DEPTHS.”]

“The cycle of the periodic overflow is measured by great intervals,” he said; “centuries are required to raise the level of the lake a fraction of an inch, and thousands of years may elapse before its surface will again reach the top of the adamantine wall. Then, governed by the law that attracts a liquid to itself, and heaps the teaspoon with liquid, the water of the quiet lake piles upon this narrow wall, forming a ledge along its summit. Finally the superimposed surface water gives way, and a skim of water pours over into the abyss.”

He paused; I leaned over and meditated, for I had now accustomed myself to the situation.

“There is no bottom,” I exclaimed.

“Upon the contrary,” he answered, “the bottom is less than ten miles beneath us, and is a great funnel-shaped orifice, the neck of the funnel reaching first down and then upward from us diagonally toward the surface of the earth. Although the light by which we are enveloped is bright, yet it is deficient in penetrating power, and is not capable of giving the contour of objects even five miles away, hence the chasm seems bottomless, and the gulf measureless.”

“Is it not natural to suppose that a mass of water like this great lake would overflow the barrier immediately, as soon as the surface reached the upper edge, for the pressure of the immense volume must be beyond calculation.”

“No, for it is height, not expanse, which, as hydrostatic engineers understand, governs the pressure of water. A liquid column, one foot in width, would press against the retaining dam with the force of a body of the same liquid, the same depth, one thousand miles in extent. Then the decrease of gravity here permits the molecular attraction of the water’s molecules to exert itself more forcibly than would be the case on the surface of the earth, and this holds the liquid mass together more firmly.”

“See,” he observed, and dipping his finger into the water he held it before him with a drop of water attached thereto (Figure 27), the globule being of considerable size, and lengthened as though it consisted of some glutinous liquid.

[Illustration: FIG. 27.]

“How can a thin stratum of water give rise to a volcanic eruption?” I next queried. “There seems to be no melted rock, no evidence of intense heat, either beneath or about us.”

“I informed you some time ago that I would partially explain these facts. Know then, that the theories of man concerning volcanic eruptions, in connection with a molten interior of the earth, are such as are evolved in ignorance of even the sub-surface of the globe. The earth’s interior is to mankind a sealed chamber, and the wise men who elucidate the curious theories concerning natural phenomena occurring therein are forced to draw entirely upon their imagination. Few persons realize the paucity of data at the command of workers in science. Theories concerning the earth are formulated from so little real knowledge of that body, that our science may be said to be all theory, with scarcely a trace of actual evidence to support it. If a globe ten inches in diameter be covered with a sheet of paper, such as I hold in my hand, the thickness of that sheet will be greater in proportion to that of such a globe than the depth men have explored within the earth is compared with the thickness of the crust of the earth. The outer surface of a pencil line represents the surface of the earth; the inner surface of the line represents the depth of man’s explorations; the highest mountain would be represented by a comma resting on the line. The geologist studies the substances that are thrust from the crater of an active volcano, and from this makes conjectures regarding the strata beneath, and the force that casts the excretions out. The results must with men, therefore, furnish evidence from which to explain the cause. It is as though an anatomist would form his idea of the anatomy of the liver by the secretion thrown out of that organ, or of the lung texture by the breath and sputum. In fact, volcanoes are of several descriptions, and usually are extremely superficial. This lake, the surface of which is but one hundred and fifty miles underground, is the mother of an exceptionally deep one. When the water pours over this ledge it strikes an element below us, the metallic base of salt, which lies in great masses in some portions of the earth’s crust.[9] Then an immediate chemical reaction ensues, the water is dissociated, intense heat results, part of the water combines with the metal, part is vaporized as steam, while part escapes as an inflammable gas. The sudden liberation of these gases causes an irregular pressure of vapor on the surface of the lake, the result being a throbbing and rebounding of the attenuated atmosphere above, which, in gigantic waves, like swelling tides, dashes great volumes of water over the ledge beside us, and into the depth below. This water in turn reacts on fresh portions of the metallic base, and the reflex action increases the vapor discharges, and as a consequence the chamber we are in becomes a gasholder, containing vapors of unequal gas pressures, and the resultant agitation of the lake from the turmoil continues, and the pulsations are repeated until the surface of the lake is lowered to such a degree as at last to prevent the water from overflowing the barrier. Finally the lake quiets itself, the gases slowly disappear by earth absorption, and by escape from the volcanic exit, and for an unrecorded period of time thereafter the surface of the lake continues to rise slowly as it is doing now.”