Perseverance Island; Or, The Robinson Crusoe of the Nineteenth Century

by Douglas Frazar

Besides all these four pipes I also made near to them an opening into the tanks, which was fitted with a screw thread, upon which I could, when occasion demanded, erect a quite large and powerful pump, that I had made for the express purpose.

One more thing remained to be done, and that was to make all around the boat inside a sort of movable step, that would ship and unship. I was well aware that, unless the centre of gravity was kept well down, my boat would capsize and spill out all the air when in use, and to prevent this I made these movable steps, which it is difficult to describe. They were made of an upright piece of wood that was over four feet in length, and on the top of which another piece of wood was nailed horizontally, some twelve inches in width, like one arm of the letter T, whilst at the other end of the upright of four feet in length was nailed another horizontal piece, some twelve inches in width, on exactly the opposite side, like the letter L; so that when the whole was done the upper horizontal board rested one foot on the top of the tanks, whilst at the other end of the upright, two feet below the bottom of the tanks, was the other horizontal board, facing in towards the centre of the boat in all directions, and forming a kind of step or shelf, upon which weights could be placed so as to prevent all chance of the capsizing of the boat, the vomiting out of its air, and perhaps the destruction of its constructor and inventor. I had this so arranged that I could speedily ship and unship it in sections, for it was of course greatly in the way, and of no use except when the boat was launched.

I then completed my deck, which I made of light planks, marked and arranged so that I could readily board over all the space in the interior or leave part of it open. Upon further thoughts, some of this deck I made permanent, leaving only a space of about six feet by four open in the forward end, which I could cover or uncover.

I then entered upon another part of the programme, namely, the motive power by which I was to move this submarine monster, but that I had long ago solved in my own mind. For some months I had been practising two fine young goats upon a treadmill fitted to their size and strength, all the time having in view the end of using them to create the motive power of my boat; and for this purpose I had left the manhole two feet square so as to be able to take them down with me into it. I now went to work and transported the treadmill to the boat, and, having fixed it in place, I each day conveyed the goats on board and set them to work, so that they might get used to it. They were already used to the motion of the mill, and I noticed that with the precision of step of their race they worked the rounds of the mill much better than horses usually do, and they soon became accustomed to the boat and worked rapidly and well, obeying the least word of command. In fact they were to me almost companions, and it would be amazing to relate, if I had time, all I have taught these really sagacious and gentle creatures since I have been on the island; not these very ones of which I am now speaking in particular, but several of their race. Perhaps before I am through with my narrative I may give an idea of the many interesting things which I taught them.

For a long time I allowed the mill to be turned daily, without making up my mind just how I would connect it with the wheel or screw that I foresaw that I should have to make to propel the boat. I at last fixed upon a propeller, to work in the open space of water in the interior of the boat, and which I readily set up with good strong gearing, that I could as readily take down by hand when needful. By means of bevelled gearing I obtained several revolutions of my propeller to one of the balance-wheel of the treadmill, and I saw, as a mechanic, that my boat would move forward, perhaps not very fast, but still at the rate of three or four knots an hour, which would answer all purposes.

I had one more necessary thing to make, and that was a rudder, which I connected to the outside of the rear tank of the boat, bringing the tiller or steering rods into the interior of the boat under the bottom of the tank. I took care to fasten the heel of the rudder, which was quite wide, above the line of the bottom of the tank, so that if the boat grounded it would not be injured or destroyed.

And now I came to the most important part of my boat, and, in fact, upon the success of which, and practical application, rested the actual consummation of all my efforts. It was to obtain a supply of air whilst under the surface of the water without connection with the atmosphere, from which I was of course debarred. This problem solved, I had, I felt, the whole matter under control,—and let it not be believed that I had proceeded thus far in my self-imposed task without seeing a way out of this difficulty. The following every-day facts were easily ascertained from my Book of Useful Arts and Sciences, and upon the following conclusions I had based my invention. It is well known that oxygen is the portion of atmospheric air which supports life, and that it composes nearly twenty-two per cent of the same, whilst nitrogen, the remaining portion, is incapable of sustaining life. It is also well known that water also contains oxygen, in the proportion of two parts to one of hydrogen, of which two gases water is composed; or, in other words whilst atmospheric air holds only twenty-two per cent of the life-giving principle, water contains about sixty-six per cent, or, by weight, eight-ninths of oxygen to one-ninth of hydrogen. I also ascertained that the specific gravity of nitrogen is 0.94, whilst that of hydrogen is only 0.0692. Now if I could release the oxygen in the water I could make new air and at the same time precipitate the nitrogen and carbonic acid in the boat, that might be in the atmosphere, that had accumulated by my repeated breathings. Now the only problem to solve was evidently how to release this oxygen with which the water was so freely impregnated, charged, or made up of, and by the breathing of which fishes sustained life. And this is how I set about to do it. I made a very light paddle-wheel, full six feet in diameter, with many, but light arms, and only six inches across the face of each paddle; this was arranged so as to ship inside the boat, upon sockets arranged so that the lower paddles would just touch the water, and was adjustable by set screws, so that the journals could be lowered or elevated as the pressure of the water in the boat might show itself, higher or lower, according to the depth the boat might be at. By this arrangement I could have the paddles, which were more like a set of large-teethed combs than paddles, dip just such distance into the water as I desired. This wheel was connected by series of light wheels to the drum of the treadmill, so that I could obtain many revolutions of the water-wheel to one of the latter. My idea was this. By violent motion of the extreme ends of my comb-paddles through the water I intended to throw up into the interior of the boat a mass of minute spray, that in that form would itself release the oxygen that it contained, or at least a large part of it, and grant to my exhausted air the vitality it needed by new oxygen, or the life-sustaining principle, and at the same time precipitate the carbonic acid that the used-up atmosphere might contain. By this simple contrivance I intended to renew my air, and thus remain just as long below the surface as I might desire. The test that I should have that my air was becoming impure would be the dimness with which the candles would burn, with which I was to furnish the boat; and if after the use of the spray-wheel they again flashed up brilliantly, I should know that my theory was correct.

I had only one more thing to make to complete the whole affair, and that was a compass, which, having finished, I took within the boat to see and note its variations from the true north on account of the attraction of the iron, and to regulate it so that I might be aware always of my true course, for upon the exactitude of this instrument rested the responsibility of my ever again reaching land should I dare to go out into the ocean, supposing that the boat should work according to my desires and theory.

For light I had nothing but the light contained in the water and my candles. I could only pass from spot to spot by compass alone, and in case of utmost disaster plunge into the water within my own boat and try to reach the surface by coming up outside. It was not my intention to propel the boat near the bottom but only when near the surface. When near the bottom a turn or two of the propeller would send me in any needed direction.