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."
[9] This view is supported in theory by a note I believe to have
somewhere seen recorded. Elsewhere other bases are mentioned
also.--J. U. L.
"But what has this phenomenon to do with the volcano?"
"It produces the eruption; the water that rushes down into the chasm,
partly as steam, partly as gas, is forced onward and upward through a
crevice that leads to the old crater of the presumed extinct but
periodically active Mount Epomeo. These gases are intensely heated, and
they move with fearful velocity. They tear off great masses of stone,
which the resultant energy disturbances, pressure, gas, and friction,
redden with heat. The mixture of gases from the decomposed water is in
large amount, is burning and exploding, and in this fiery furnace amid
such convulsions as have been described, the adjacent earth substance is
fused, and even clay is melted, and carried on with the fiery blast.
Finally the current reaches the earth's surface through the funnel
passage, the apex of which is a volcano--the blast described a volcanic
eruption."
"One thing is still obscure in my mind," I said. "You assert that the
reaction which follows the contact of the flowing water and metallic
bases in the crevice below us liberates the explosive gases, and also
volumes of vapor of water. These gases rush, you say, and produce a
volcanic eruption in a distant part of the crust of the earth. I can not
understand why they do not rush backward as well, and produce another
eruption in Kentucky. Surely the pressure of a gas in confinement is the
same in all directions, is it not?"
"Yes," he replied, "but the conditions in the different directions are
dissimilar. In the direction of the Kentucky cavern, the passage is
tortuous, and often contracts to a narrow crevice. In one place near the
cavern's mouth, as you will remember, we had to dive beneath the surface
of a stream of water. That stratum of water as effectually closed the
exit from the earth as the stopper prevents water escaping from a
bottle. Between the point we now occupy and that water stopper, rest
thousands of miles of quiescent air. The inertia of a thousand miles of
air is great beyond your comprehension. To move that column of air by
pushing against this end of it, and thus shoving it instantly out of the
other end, would require greater force than would burst the one hundred
and fifty miles of inelastic stone above us. Then, the friction of the
sides is another thing that prevents its accomplishment. While a
gradually applied pressure would in time overcome both the inertia of
the air and the friction of the stone passages, it would take a supply
of energy greater than you can imagine to start into motion the elastic
mass that stands as solid and immovable as a sentinel of adamant,
between the cavern you entered, and the spot we now occupy. Time and
energy combined would be able to accomplish the result, but not under
present conditions.
"In the other direction a broad open channel reaches directly to and
connects with the volcanic shaft. Through this channel the air is in
motion, moving towards the extinct crater, being supplied from another
surface orifice. The gases liberated in the manner I have described,
naturally follow the line of least resistance. They turn at once away
from the inert mass of air that rests behind us, and move with
increasing velocity towards the volcanic exit. Before the pressure that
might be exerted towards the Kentucky cavern would have more than
compressed the intervening column of air enough to raise the water of a
well from its usual level to the surface of the earth, the velocity in
the other direction would have augmented prodigiously, and with its
increased rapidity a suction would follow more than sufficient to
consume the increasingly abundant gases from behind."
"Volcanoes are therefore local, and the interior of the earth is not a
molten mass as I have been taught," I exclaimed.
He answered: "If men were far enough along in their thought journey (for
the evolution of the mental side of man is a journey in the world of
thought), they would avoid such theories as that which ascribes a
molten interior to the earth. Volcanoes are superficial. They are as a
rule, when in activity but little blisters or excoriations upon the
surface of the earth, although their underground connections may be
extensive. Some of them are in a continual fret with frequent eruptions,
others, like the one under consideration, awaken only after great
periods of time. The entire surface of this globe has been or will be
subject to volcanic action. The phenomenon is one of the steps in the
world-making, matter-leveling process. When the deposit of substances
that I have indicated, and of which much of the earth's interior is
composed, the bases of salt, potash, and lime and clay is exhausted,
there will be no further volcanic action from this cause, and in some
places, this deposit has already disappeared, or is covered deeply by
layers of earth that serve as a protection."
"Is water, then, the universal cause of volcanoes?"
"Water and air together cause most of them. The action of water and its
vapor produces from metallic space dust, limestone, and clay soil,
potash and soda salts. This perfectly rational and natural action must
continue as long as there is water above, and free elementary bases in
contact with the earth bubbles. Volcanoes, earthquakes, geysers, mud
springs, and hot springs, are the natural result of that reaction.
Mountains are thereby forming by upheavals from beneath, and the
corresponding surface valleys are consequently filling up, either by the
slow deposit of the matter from the saline water of hot springs, or by
the sudden eruption of a new or presumably extinct volcano."
"What would happen if a crevice in the bottom of the ocean should
conduct the waters of the ocean into a deposit of metallic bases?"
"That often occurs," was the reply; "a volcanic wave results, and a
volcano may thus rise from the ocean's depths."
"Is there any danger to the earth itself? May it not be riven into
fragments from such a convulsion?" I hesitatingly questioned.
"No; while the configuration of continents is continually being altered,
each disturbance must be practically superficial, and of limited area."
"But," I persisted, "the rigid, solid earth may be blown to fragments;
in such convulsions a result like that seems not impossible."
"You argue from an erroneous hypothesis. The earth is neither rigid nor
solid."
"True," I answered. "If it were solid I could not be a hundred miles
beneath its surface in conversation with another being; but there can
not be many such cavities as that which we are now traversing, and they
can not surely extend entirely through its mass; the great weight of the
superincumbent material would crush together the strongest materials, if
a globe as large as our earth were extensively honeycombed in this
manner."
"Quite the contrary," he replied; "and here let me, for the first time,
enlighten you as to the interior structure of the terrestrial globe. The
earth-forming principle consists of an invisible sphere of energy that,
spinning through space, supports the space dust which collects on it, as
dust on a bubble. By gradual accumulation of substance on that sphere a
hollow ball has resulted, on the outer surface of which you have
hitherto dwelt. The crust of the earth is comparatively thin, not more
than eight hundred miles in average thickness, and is held in position
by the central sphere of energy that now exists at a distance about
seven hundred miles beneath the ocean level. The force inherent to this
sphere manifests itself upon the matter which it supports on both sides,
rendering matter the lighter the nearer it lies to the center sphere. In
other words, let me say to you: The crust, or shell, which I have just
described as being but about eight hundred miles in thickness, is firm
and solid on both its convex and concave surface, but gradually loses in
weight, whether we penetrate from the outer surface toward the center,
or from any point of the inner surface towards the outside, until at the
central sphere matter has no weight at all. Do you conceive my meaning?"
"Yes," I replied; "I understand you perfectly."
After a pause my pilot asked me abruptly:
"What do you most desire?"
The question caused my mind to revert instantly to my old home on the
earth above me, and although I felt the hope of returning to it spring
up in my heart, the force of habit caused me involuntarily to answer,
"More light!"
"More light being your desire, you shall receive it."
Obedient to his touch, the bow of the boat turned from the gulf we had
been considering towards the center of the lake; the responsive craft
leaped forward, and in an instant the obsidian parapet disappeared
behind us. On and over the trackless waste of glass-like water we sped,
until the dead silence became painfully oppressive, and I asked:
"Whither are we bound?"
"Towards the east."
The well-timed answer raised my spirits; I thought again that in this
man, despite his repulsive shape, I beheld a friend, a brother;
suspicion vanished, and my courage rose. He touched the lever, and the
craft, subject to his will, nearly rose from the water, and sped with
amazing velocity, as was evident from the appearance of the luminous
road behind us. So rapid was our flight that the wake of the boat seemed
as if made of rigid parallel lines that disappeared in the distance, too
quick for the eye to catch the tremor.
Continuing his conversation, my companion informed me that he had now
directed the bark toward a point east of the spot where we struck the
shore, after crossing the lake, in order that we might continue our
journey downward, diagonally to the under surface of the earth crust.
"This recent digression from our journey proper," said he, "has been
made to acquaint you with a subject, regarding which you have exhibited
a curiosity, and about which you have heretofore been misinformed; now
you understand more clearly part of the philosophy of volcanoes and
earthquakes. You have yet much to learn in connection with allied
phenomena, but this study of the crude exhibition of force-disturbed
matter, the manipulation of which is familiar to man under the above
names, is an introduction to the more wonderful study destined yet to be
a part of your field, an investigation of quiescent matter, and pure
motion."
"I can not comprehend you," I replied, "as I stated once before when you
referred to what you designated as pure motion."