Some Figures
A MOMENT LATER we were seated on a couch in the lounge, cigars between
our lips. The captain placed before my eyes a working drawing that
gave the ground plan, cross section, and side view of the
Nautilus. Then he began his description as follows:
“Here, Professor Aronnax, are the different dimensions of this boat
now transporting you. It’s a very long cylinder with conical ends. It
noticeably takes the shape of a cigar, a shape already adopted in
London for several projects of the same kind. The length of this
cylinder from end to end is exactly seventy meters, and its maximum
breadth of beam is eight meters. So it isn’t quite built on the
ten-to-one ratio of your high-speed steamers; but its lines are
sufficiently long, and their tapering gradual enough, so that the
displaced water easily slips past and poses no obstacle to the ship’s
movements.
“These two dimensions allow you to obtain, via a simple calculation,
the surface area and volume of the Nautilus. Its surface area totals
1,011.45 square meters, its volume 1,507.2 cubic meters—which is
tantamount to saying that when it’s completely submerged, it displaces
1,500 cubic meters of water, or weighs 1,500 metric tons.
“In drawing up plans for a ship meant to navigate underwater, I wanted
it, when floating on the waves, to lie nine-tenths below the surface
and to emerge only one-tenth. Consequently, under these conditions it
needed to displace only nine-tenths of its volume, hence 1,356.48
cubic meters; in other words, it was to weigh only that same number of
metric tons. So I was obliged not to exceed this weight while building
it to the aforesaid dimensions.
“The Nautilus is made up of two hulls, one inside the other; between
them, joining them together, are iron T-bars that give this ship the
utmost rigidity. In fact, thanks to this cellular arrangement, it has
the resistance of a stone block, as if it were completely solid. Its
plating can’t give way; it’s self-adhering and not dependent on the
tightness of its rivets; and due to the perfect union of its
materials, the solidarity of its construction allows it to defy the
most violent seas.
“The two hulls are manufactured from boilerplate steel, whose relative
density is 7.8 times that of water. The first hull has a thickness of
no less than five centimeters and weighs 394.96 metric tons. My second
hull, the outer cover, includes a keel fifty centimeters high by
twenty-five wide, which by itself weighs 62 metric tons; this hull,
the engine, the ballast, the various accessories and accommodations,
plus the bulkheads and interior braces, have a combined weight of
961.52 metric tons, which when added to 394.96 metric tons, gives us
the desired total of 1,356.48 metric tons. Clear?”
“Clear,” I replied.
“So,” the captain went on, “when the Nautilus lies on the waves under
these conditions, one-tenth of it does emerge above water. Now then,
if I provide some ballast tanks equal in capacity to that one-tenth,
hence able to hold 150.72 metric tons, and if I fill them with water,
the boat then displaces 1,507.2 metric tons—or it weighs that much—and
it would be completely submerged. That’s what comes about,
professor. These ballast tanks exist within easy access in the lower
reaches of the Nautilus. I open some stopcocks, the tanks fill, the
boat sinks, and it’s exactly flush with the surface of the water.”
“Fine, captain, but now we come to a genuine difficulty. You’re able
to lie flush with the surface of the ocean, that I understand. But
lower down, while diving beneath that surface, isn’t your submersible
going to encounter a pressure, and consequently undergo an upward
thrust, that must be assessed at one atmosphere per every thirty feet
of water, hence at about one kilogram per each square centimeter?”
“Precisely, sir.”
“Then unless you fill up the whole Nautilus, I don’t see how you can
force it down into the heart of these liquid masses.”
“Professor,” Captain Nemo replied, “static objects mustn’t be confused
with dynamic ones, or we’ll be open to serious error. Comparatively
little effort is spent in reaching the ocean’s lower regions, because
all objects have a tendency to become ‘sinkers.’ Follow my logic
here.”
“I’m all ears, captain.”
“When I wanted to determine what increase in weight the Nautilus
needed to be given in order to submerge, I had only to take note of
the proportionate reduction in volume that salt water experiences in
deeper and deeper strata.”
“That’s obvious,” I replied.
“Now then, if water isn’t absolutely incompressible, at least it
compresses very little. In fact, according to the most recent
calculations, this reduction is only .0000436 per atmosphere, or per
every thirty feet of depth. For instance, to go 1,000 meters down, I
must take into account the reduction in volume that occurs under a
pressure equivalent to that from a 1,000-meter column of water, in
other words, under a pressure of 100 atmospheres. In this instance the
reduction would be .00436. Consequently, I’d have to increase my
weight from 1,507.2 metric tons to 1,513.77. So the added weight would
only be 6.57 metric tons.”
“That’s all?”
“That’s all, Professor Aronnax, and the calculation is easy to
check. Now then, I have supplementary ballast tanks capable of
shipping 100 metric tons of water. So I can descend to considerable
depths. When I want to rise again and lie flush with the surface, all
I have to do is expel that water; and if I desire that the Nautilus
emerge above the waves to one-tenth of its total capacity, I empty all
the ballast tanks completely.”
This logic, backed up by figures, left me without a single objection.
“I accept your calculations, captain,” I replied, “and I’d be
ill-mannered to dispute them, since your daily experience bears them
out. But at this juncture, I have a hunch that we’re still left with
one real difficulty.”
“What’s that, sir?”
“When you’re at a depth of 1,000 meters, the Nautilus’s plating bears
a pressure of 100 atmospheres. If at this point you want to empty the
supplementary ballast tanks in order to lighten your boat and rise to
the surface, your pumps must overcome that pressure of 100
atmospheres, which is 100 kilograms per each square centimeter. This
demands a strength—”
“That electricity alone can give me,” Captain Nemo said swiftly. “Sir,
I repeat: the dynamic power of my engines is nearly infinite. The
Nautilus’s pumps have prodigious strength, as you must have noticed
when their waterspouts swept like a torrent over the Abraham
Lincoln. Besides, I use my supplementary ballast tanks only to reach
an average depth of 1,500 to 2,000 meters, and that with a view to
conserving my machinery. Accordingly, when I have a mind to visit the
ocean depths two or three vertical leagues beneath the surface, I use
maneuvers that are more time-consuming but no less infallible.”
“What are they, captain?” I asked.
“Here I’m naturally led into telling you how the Nautilus is
maneuvered.”
“I can’t wait to find out.”
“In order to steer this boat to port or starboard, in short, to make
turns on a horizontal plane, I use an ordinary, wide-bladed rudder
that’s fastened to the rear of the sternpost and worked by a wheel and
tackle. But I can also move the Nautilus upward and downward on a
vertical plane by the simple method of slanting its two fins, which
are attached to its sides at its center of flotation; these fins are
flexible, able to assume any position, and can be operated from inside
by means of powerful levers. If these fins stay parallel with the
boat, the latter moves horizontally. If they slant, the Nautilus
follows the angle of that slant and, under its propeller’s thrust,
either sinks on a diagonal as steep as it suits me, or rises on that
diagonal. And similarly, if I want to return more swiftly to the
surface, I throw the propeller in gear, and the water’s pressure makes
the Nautilus rise vertically, as an air balloon inflated with hydrogen
lifts swiftly into the skies.”
“Bravo, captain!” I exclaimed. “But in the midst of the waters, how
can your helmsman follow the course you’ve given him?”
“My helmsman is stationed behind the windows of a pilothouse, which
protrudes from the topside of the Nautilus’s hull and is fitted with
biconvex glass.”
“Is glass capable of resisting such pressures?”
“Perfectly capable. Though fragile on impact, crystal can still offer
considerable resistance. In 1864, during experiments on fishing by
electric light in the middle of the North Sea, glass panes less than
seven millimeters thick were seen to resist a pressure of sixteen
atmospheres, all the while letting through strong, heat-generating
rays whose warmth was unevenly distributed. Now then, I use glass
windows measuring no less than twenty-one centimeters at their
centers; in other words, they’ve thirty times the thickness.”
“Fair enough, captain, but if we’re going to see, we need light to
drive away the dark, and in the midst of the murky waters, I wonder
how your helmsman can—”
“Set astern of the pilothouse is a powerful electric reflector whose
rays light up the sea for a distance of half a mile.”
“Oh, bravo! Bravo three times over, captain! That explains the
phosphorescent glow from this so-called narwhale that so puzzled us
scientists! Pertinent to this, I’ll ask you if the Nautilus’s running
afoul of the Scotia, which caused such a great uproar, was the result
of an accidental encounter?”
“Entirely accidental, sir. I was navigating two meters beneath the
surface of the water when the collision occurred. However, I could see
that it had no dire consequences.”
“None, sir. But as for your encounter with the Abraham Lincoln
. . . ?”
“Professor, that troubled me, because it’s one of the best ships in
the gallant American navy, but they attacked me and I had to defend
myself! All the same, I was content simply to put the frigate in a
condition where it could do me no harm; it won’t have any difficulty
getting repairs at the nearest port.”
“Ah, commander,” I exclaimed with conviction, “your Nautilus is truly
a marvelous boat!”
“Yes, professor,” Captain Nemo replied with genuine excitement, “and I
love it as if it were my own flesh and blood! Aboard a conventional
ship, facing the ocean’s perils, danger lurks everywhere; on the
surface of the sea, your chief sensation is the constant feeling of an
underlying chasm, as the Dutchman Jansen so aptly put it; but below
the waves aboard the Nautilus, your heart never fails you! There are
no structural deformities to worry about, because the double hull of
this boat has the rigidity of iron; no rigging to be worn out by
rolling and pitching on the waves; no sails for the wind to carry off;
no boilers for steam to burst open; no fires to fear, because this
submersible is made of sheet iron not wood; no coal to run out of,
since electricity is its mechanical force; no collisions to fear,
because it navigates the watery deep all by itself; no storms to
brave, because just a few meters beneath the waves, it finds absolute
tranquility! There, sir. There’s the ideal ship! And if it’s true that
the engineer has more confidence in a craft than the builder, and the
builder more than the captain himself, you can understand the utter
abandon with which I place my trust in this Nautilus, since I’m its
captain, builder, and engineer all in one!”
Captain Nemo spoke with winning eloquence. The fire in his eyes and
the passion in his gestures transfigured him. Yes, he loved his ship
the same way a father loves his child!
But one question, perhaps indiscreet, naturally popped up, and I
couldn’t resist asking it.
“You’re an engineer, then, Captain Nemo?”
“Yes, professor,” he answered me. “I studied in London, Paris, and New
York back in the days when I was a resident of the earth’s
continents.”
“But how were you able to build this wonderful Nautilus in secret?”
“Each part of it, Professor Aronnax, came from a different spot on the
globe and reached me at a cover address. Its keel was forged by
Creusot in France, its propeller shaft by Pen & Co. in London, the
sheet-iron plates for its hull by Laird’s in Liverpool, its propeller
by Scott’s in Glasgow. Its tanks were manufactured by Cail & Co. in
Paris, its engine by Krupp in Prussia, its spur by the Motala
workshops in Sweden, its precision instruments by Hart Bros. in New
York, etc.; and each of these suppliers received my specifications
under a different name.”
“But,” I went on, “once these parts were manufactured, didn’t they
have to be mounted and adjusted?”
“Professor, I set up my workshops on a deserted islet in
midocean. There our Nautilus was completed by me and my workmen, in
other words, by my gallant companions whom I’ve molded and
educated. Then, when the operation was over, we burned every trace of
our stay on that islet, which if I could have, I’d have blown up.”
“From all this, may I assume that such a boat costs a fortune?”
“An iron ship, Professor Aronnax, runs 1,125 francs per metric
ton. Now then, the Nautilus has a burden of 1,500 metric
tons. Consequently, it cost 1,687,000 francs, hence 2,000,000 francs
including its accommodations, and 4,000,000 or 5,000,000 with all the
collections and works of art it contains.”
“One last question, Captain Nemo.”
“Ask, professor.”
“You’re rich, then?”
“Infinitely rich, sir, and without any trouble, I could pay off the
ten-billion-franc French national debt!”
I gaped at the bizarre individual who had just spoken these words. Was
he playing on my credulity? Time would tell.