Part One.: Chapter 12: Some Figures

by Jules Verne

　　A moment after we were seated on a divan in the saloon smoking.The Captain showed me a sketch that gave the plan, section, and elevationof the Nautilus. Then he began his description in these words:

　　"Here, M. Aronnax, are the several dimensions of the boatyou are in. It is an elongated cylinder with conical ends.It is very like a cigar in shape, a shape already adoptedin London in several constructions of the same sort.The length of this cylinder, from stem to stern, is exactly232 feet, and its maximum breadth is twenty-six feet.It is not built quite like your long-voyage steamers,but its lines are sufficiently long, and its curvesprolonged enough, to allow the water to slide off easily,and oppose no obstacle to its passage. These two dimensionsenable you to obtain by a simple calculation the surface andcubic contents of the Nautilus. Its area measures 6,032 feet;and its contents about 1,500 cubic yards; that is to say,when completely immersed it displaces 50,000 feet of water,or weighs 1,500 tons.

　　"When I made the plans for this submarine vessel, I meant that nine-tenthsshould be submerged: consequently it ought only to displace nine-tenthsof its bulk, that is to say, only to weigh that number of tons.I ought not, therefore, to have exceeded that weight, constructing it onthe aforesaid dimensions.

　　"The Nautilus is composed of two hulls, one inside, the other outside,joined by T-shaped irons, which render it very strong. Indeed, owing tothis cellular arrangement it resists like a block, as if it were solid.Its sides cannot yield; it coheres spontaneously, and not by the closenessof its rivets; and its perfect union of the materials enables it to defythe roughest seas.

　　"These two hulls are composed of steel plates, whose density isfrom .7 to .8 that of water. The first is not less than two inchesand a half thick and weighs 394 tons. The second envelope, the keel,twenty inches high and ten thick, weighs only sixty-two tons.The engine, the ballast, the several accessories and apparatusappendages, the partitions and bulkheads, weigh 961.62 tons.Do you follow all this?"

　　"I do."

　　"Then, when the Nautilus is afloat under these circumstances,one-tenth is out of the water. Now, if I have made reservoirsof a size equal to this tenth, or capable of holding 150 tons,and if I fill them with water, the boat, weighing then 1,507 tons,will be completely immersed. That would happen, Professor.These reservoirs are in the lower part of the Nautilus.I turn on taps and they fill, and the vessel sinks that had justbeen level with the surface."

　　"Well, Captain, but now we come to the real difficulty.I can understand your rising to the surface; but, diving belowthe surface, does not your submarine contrivance encounter a pressure,and consequently undergo an upward thrust of one atmospherefor every thirty feet of water, just about fifteen poundsper square inch?"

　　"Just so, sir."

　　"Then, unless you quite fill the Nautilus, I do not see how youcan draw it down to those depths."

　　"Professor, you must not confound statics with dynamics or you will beexposed to grave errors. There is very little labour spent in attainingthe lower regions of the ocean, for all bodies have a tendency to sink.When I wanted to find out the necessary increase of weight requiredto sink the Nautilus, I had only to calculate the reduction of volumethat sea-water acquires according to the depth."

　　"That is evident."

　　"Now, if water is not absolutely incompressible, it is at least capableof very slight compression. Indeed, after the most recent calculations thisreduction is only .000436 of an atmosphere for each thirty feet of depth.If we want to sink 3,000 feet, I should keep account of the reduction of bulkunder a pressure equal to that of a column of water of a thousand feet.The calculation is easily verified. Now, I have supplementaryreservoirs capable of holding a hundred tons. Therefore I can sinkto a considerable depth. When I wish to rise to the level of the sea,I only let off the water, and empty all the reservoirs if I want the Nautilusto emerge from the tenth part of her total capacity."

　　I had nothing to object to these reasonings.

　　"I admit your calculations, Captain," I replied; "I should bewrong to dispute them since daily experience confirms them;but I foresee a real difficulty in the way."

　　"What, sir?"

　　"When you are about 1,000 feet deep, the walls of the Nautilusbear a pressure of 100 atmospheres. If, then, just now you wereto empty the supplementary reservoirs, to lighten the vessel,and to go up to the surface, the pumps must overcome the pressureof 100 atmospheres, which is 1,500 lbs. per square inch.From that a power----"

　　"That electricity alone can give," said the Captain, hastily."I repeat, sir, that the dynamic power of my engines is almost infinite.The pumps of the Nautilus have an enormous power, as you must have observedwhen their jets of water burst like a torrent upon the Abraham Lincoln.Besides, I use subsidiary reservoirs only to attain a mean depth of 750to 1,000 fathoms, and that with a view of managing my machines.Also, when I have a mind to visit the depths of the ocean five or six mllesbelow the surface, I make use of slower but not less infallible means."

　　"What are they, Captain?"

　　"That involves my telling you how the Nautilus is worked."

　　"I am impatient to learn."

　　"To steer this boat to starboard or port, to turn, in a word,following a horizontal plan, I use an ordinary rudder fixed on the backof the stern-post, and with one wheel and some tackle to steer by.But I can also make the Nautilus rise and sink, and sink and rise,by a vertical movement by means of two inclined planes fastened to its sides,opposite the centre of flotation, planes that move in every direction,and that are worked by powerful levers from the interior.If the planes are kept parallel with the boat, it moves horizontally.If slanted, the Nautilus, according to this inclination, and underthe influence of the screw, either sinks diagonally or rises diagonallyas it suits me. And even if I wish to rise more quickly to the surface,I ship the screw, and the pressure of the water causes the Nautilusto rise vertically like a balloon filled with hydrogen."

　　"Bravo, Captain! But how can the steersman follow the routein the middle of the waters?"

　　"The steersman is placed in a glazed box, that is raised about the hullof the Nautilus, and furnished with lenses."

　　"Are these lenses capable of resisting such pressure?"

　　"Perfectly. Glass, which breaks at a blow, is, nevertheless, capable ofoffering considerable resistance. During some experiments of fishingby electric light in 1864 in the Northern Seas, we saw plates lessthan a third of an inch thick resist a pressure of sixteen atmospheres.Now, the glass that I use is not less than thirty times thicker."

　　"Granted. But, after all, in order to see, the light must exceedthe darkness, and in the midst of the darkness in the water,how can you see?"

　　"Behind the steersman's cage is placed a powerful electric reflector,the rays from which light up the sea for half a mile in front."

　　"Ah! bravo, bravo, Captain! Now I can account for thisphosphorescence in the supposed narwhal that puzzled us so.I now ask you if the boarding of the Nautilus and of the Scotia,that has made such a noise, has been the result of a chance rencontre?"

　　"Quite accidental, sir. I was sailing only one fathombelow the surface of the water when the shock came.It had no bad result."

　　"None, sir. But now, about your rencontre with the Abraham Lincoln?"

　　"Professor, I am sorry for one of the best vessels in the American navy;but they attacked me, and I was bound to defend myself.I contented myself, however, with putting the frigate hors de combat;she will not have any difficulty in getting repaired at the next port."

　　"Ah, Commander! your Nautilus is certainly a marvellous boat."

　　"Yes, Professor; and I love it as if it were part of myself.If danger threatens one of your vessels on the ocean,the first impression is the feeling of an abyss above and below.On the Nautilus men's hearts never fail them. No defectsto be afraid of, for the double shell is as firm as iron;no rigging to attend to; no sails for the wind to carry away;no boilers to burst; no fire to fear, for the vessel is madeof iron, not of wood; no coal to run short, for electricityis the only mechanical agent; no collision to fear, for italone swims in deep water; no tempest to brave, for when itdives below the water it reaches absolute tranquillity.There, sir! that is the perfection of vessels! And if it is truethat the engineer has more confidence in the vessel than the builder,and the builder than the captain himself, you understandthe trust I repose in my Nautilus; for I am at once captain,builder, and engineer."

　　"But how could you construct this wonderful Nautilus in secret?"

　　"Each separate portion, M. Aronnax, was brought from differentparts of the globe."

　　"But these parts had to be put together and arranged?"

　　"Professor, I had set up my workshops upon a desert island in the ocean.There my workmen, that is to say, the brave men that I instructedand educated, and myself have put together our Nautilus. Then, when the workwas finished, fire destroyed all trace of our proceedings on this island,that I could have jumped over if I had liked."

　　"Then the cost of this vessel is great?"

　　"M. Aronnax, an iron vessel costs L145 per ton. Now the Nautilus weighed1,500. It came therefore to L67,500, and L80,000 more for fitting it up,and about L200,000, with the works of art and the collections it contains."

　　"One last question, Captain Nemo."

　　"Ask it, Professor."

　　"You are rich?"

　　"Immensely rich, sir; and I could, without missing it,pay the national debt of France."

　　I stared at the singular person who spoke thus. Was he playingupon my credulity? The future would decide that.