<h2><SPAN name="CHAPTER_15" id="CHAPTER_15"></SPAN>CHAPTER 15</h2>
<h4>WE CONTINUE OUR DESCENT</h4>
<p>At eight o'clock the next morning, a faint kind of dawn of day awoke us.
The thousand and one prisms of the lava collected the light as it passed
and brought it to us like a shower of sparks.</p>
<p>We were able with ease to see objects around us.</p>
<p>"Well, Harry, my boy," cried the delighted Professor, rubbing his hands
together, "what say you now? Did you ever pass a more tranquil night in
our house in the Konigstrasse? No deafening sounds of cart wheels, no
cries of hawkers, no bad language from boatmen or watermen!"</p>
<p>"Well, Uncle, we are quite at the bottom of this well—but to me there
is something terrible in this calm."</p>
<p>"Why," said the Professor hotly, "one would say you were already
beginning to be afraid. How will you get on presently? Do you know, that
as yet, we have not penetrated one inch into the bowels of the earth."</p>
<p>"What can you mean, sir?" was my bewildered and astonished reply.</p>
<p>"I mean to say that we have only just reached the soil of the island
itself. This long vertical tube, which ends at the bottom of the crater
of Sneffels, ceases here just about on a level with the sea."</p>
<p>"Are you sure, sir?"</p>
<p>"Quite sure. Consult the barometer."</p>
<p>It was quite true that the mercury, after rising gradually in the
instrument, as long as our descent was taking place, had stopped
precisely at twenty-nine degrees.</p>
<p>"You perceive," said the Professor, "we have as yet only to endure the
pressure of air. I am curious to replace the barometer by the
manometer."</p>
<p>The barometer, in fact, was about to become useless—as soon as the
weight of the air was greater than what was calculated as above the
level of the ocean.</p>
<p>"But," said I, "is it not very much to be feared that this
ever-increasing pressure may not in the end turn out very painful and
inconvenient?"</p>
<p>"No," said he. "We shall descend very slowly, and our lungs will be
gradually accustomed to breathe compressed air. It is well known that
aeronauts have gone so high as to be nearly without air at all—why,
then, should we not accustom ourselves to breathe when we have, say, a
little too much of it? For myself, I am certain I shall prefer it. Let
us not lose a moment. Where is the packet which preceded us in our
descent?"</p>
<p>I smilingly pointed it out to my uncle. Hans had not seen it, and
believed it caught somewhere above us: "Huppe" as he phrased it.</p>
<p>"Now," said my uncle, "let us breakfast, and break fast like people who
have a long day's work before them."</p>
<p>Biscuit and dried meat, washed down by some mouthfuls of water flavored
with Schiedam, was the material of our luxurious meal.</p>
<p>As soon as it was finished, my uncle took from his pocket a notebook
destined to be filled by memoranda of our travels. He had already placed
his instruments in order, and this is what he wrote:</p>
<div class="blockquot">
<p>Monday, June 29th</p>
<p>Chronometer, 8h. 17m. morning.</p>
<p>Barometer, 29.6 inches.</p>
<p>Thermometer, 6 degrees [43 degrees Fahr.]</p>
<p>Direction, E.S.E.</p>
</div>
<p>This last observation referred to the obscure gallery, and was indicated
to us by the compass.</p>
<p>"Now, Harry," cried the Professor, in an enthusiastic tone of voice, "we
are truly about to take our first step into the Interior of the Earth;
never before visited by man since the first creation of the world. You
may consider, therefore, that at this precise moment our travels really
commence."</p>
<p>As my uncle made this remark, he took in one hand the Ruhmkorff coil
apparatus, which hung round his neck, and with the other he put the
electric current into communication with the worm of the lantern. And a
bright light at once illumined that dark and gloomy tunnel!</p>
<p>The effect was magical!</p>
<p>Hans, who carried the second apparatus, had it also put into operation.
This ingenious application of electricity to practical purposes enabled
us to move along by the light of an artificial day, amid even the flow
of the most inflammable and combustible gases.</p>
<p>"Forward!" cried my uncle. Each took up his burden. Hans went first, my
uncle followed, and I going third, we entered the somber gallery!</p>
<p>Just as we were about to engulf ourselves in this dismal passage, I
lifted up my head, and through the tubelike shaft saw that Iceland sky I
was never to see again!</p>
<p>Was it the last I should ever see of any sky?</p>
<p>The stream of lava flowing from the bowels of the earth in 1219 had
forced itself a passage through the tunnel. It lined the whole of the
inside with its thick and brilliant coating. The electric light added
very greatly to the brilliancy of the effect.</p>
<p>The great difficulty of our journey now began. How were we to prevent
ourselves from slipping down the steeply inclined plane? Happily some
cracks, abrasures of the soil, and other irregularities, served the
place of steps; and we descended slowly; allowing our heavy luggage to
slip on before, at the end of a long cord.</p>
<p>But that which served as steps under our feet became in other places
stalactites. The lava, very porous in certain places, took the form of
little round blisters. Crystals of opaque quartz, adorned with limpid
drops of natural glass suspended to the roof like lusters, seemed to
take fire as we passed beneath them. One would have fancied that the
genii of romance were illuminating their underground palaces to receive
the sons of men.</p>
<p>"Magnificent, glorious!" I cried in a moment of involuntary enthusiasm,
"What a spectacle, Uncle! Do you not admire these variegated shades of
lava, which run through a whole series of colors, from reddish brown to
pale yellow—by the most insensible degrees? And these crystals, they
appear like luminous globes."</p>
<p>"You are beginning to see the charms of travel, Master Harry," cried my
uncle. "Wait a bit, until we advance farther. What we have as yet
discovered is nothing—onwards, my boy, onwards!"</p>
<p>It would have been a far more correct and appropriate expression, had he
said, "let us slide," for we were going down an inclined plane with
perfect ease. The compass indicated that we were moving in a
southeasterly direction. The flow of lava had never turned to the right
or the left. It had the inflexibility of a straight line.</p>
<p>Nevertheless, to my surprise, we found no perceptible increase in heat.
This proved the theories of Humphry Davy to be founded on truth, and
more than once I found myself examining the thermometer in silent
astonishment.</p>
<p>Two hours after our departure it only marked fifty-four degrees
Fahrenheit. I had every reason to believe from this that our descent was
far more horizontal than vertical. As for discovering the exact depth to
which we had attained, nothing could be easier. The Professor as he
advanced measured the angles of deviation and inclination; but he kept
the result of his observations to himself.</p>
<p>About eight o'clock in the evening, my uncle gave the signal for
halting. Hans seated himself on the ground. The lamps were hung to
fissures in the lava rock. We were now in a large cavern where air was
not wanting. On the contrary, it abounded. What could be the cause of
this—to what atmospheric agitation could be ascribed this draught? But
this was a question which I did not care to discuss just then. Fatigue
and hunger made me incapable of reasoning. An unceasing march of seven
hours had not been kept up without great exhaustion. I was really and
truly worn out; and delighted enough I was to hear the word Halt.</p>
<p>Hans laid out some provisions on a lump of lava, and we each supped with
keen relish. One thing, however, caused us great uneasiness—our water
reserve was already half exhausted. My uncle had full confidence in
finding subterranean resources, but hitherto we had completely failed in
so doing. I could not help calling my uncle's attention to the
circumstance.</p>
<p>"And you are surprised at this total absence of springs?" he said.</p>
<p>"Doubtless—I am very uneasy on the point. We have certainly not enough
water to last us five days."</p>
<p>"Be quite easy on that matter," continued my uncle. "I answer for it we
shall find plenty of water—in fact, far more than we shall want."</p>
<p>"But when?"</p>
<p>"When we once get through this crust of lava. How can you expect springs
to force their way through these solid stone walls?"</p>
<p>"But what is there to prove that this concrete mass of lava does not
extend to the centre of the earth? I don't think we have as yet done
much in a vertical way."</p>
<p>"What puts that into your head, my boy?" asked my uncle mildly.</p>
<p>"Well, it appears to me that if we had descended very far below the
level of the sea—we should find it rather hotter than we have."</p>
<p>"According to your system," said my uncle; "but what does the
thermometer say?"</p>
<p>"Scarcely fifteen degrees by Reaumur, which is only an increase of nine
since our departure."</p>
<p>"Well, and what conclusion does that bring you to?" inquired the
Professor.</p>
<p>"The deduction I draw from this is very simple. According to the most
exact observations, the augmentation of the temperature of the interior
of the earth is one degree for every hundred feet. But certain local
causes may considerably modify this figure. Thus at Yakoust in Siberia,
it has been remarked that the heat increases a degree every thirty-six
feet. The difference evidently depends on the conductibility of certain
rocks. In the neighborhood of an extinct volcano, it has been remarked
that the elevation of temperature was only one degree in every
five-and-twenty feet. Let us, then, go upon this calculation—which is
the most favorable—and calculate."</p>
<p>"Calculate away, my boy."</p>
<p>"Nothing easier," said I, pulling out my notebook and pencil. "Nine
times one hundred and twenty-five feet make a depth of eleven hundred
and twenty-five feet."</p>
<p>"Archimedes could not have spoken more geometrically."</p>
<p>"Well?"</p>
<p>"Well, according to my observations, we are at least ten thousand feet
below the level of the sea."</p>
<p>"Can it be possible?"</p>
<p>"Either my calculation is correct, or there is no truth in figures."</p>
<p>The calculations of the Professor were perfectly correct. We were
already six thousand feet deeper down in the bowels of the earth than
anyone had ever been before. The lowest known depth to which man had
hitherto penetrated was in the mines of Kitzbuhel, in the Tirol, and
those of Wurttemberg.</p>
<p>The temperature, which should have been eighty-one, was in this place
only fifteen. This was a matter for serious consideration.</p>
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