Provided the hull of the vessel be composed of number of small divisions, similar to the life preservers constructed by Mr. Daniel, it will scarcely be possible to sink it, especially if a large sheet, well prepared with oakum, be drawn under the vessel in the event of a fracture occurring, as the pressure of the water on the surface of the vessel will force the canvass into the chasm, and allow of the necessary reparation. The latter method has been adopted in the navy for several years. No. XIII. How to make such false decks, as in a moment should kill and take prisoners as many as should board the ship, without blowing the real decks up, or destroying them from being reducible; and, in a quarter of an hour's time, should recover their former shape, and to be made fit for any employment without discovering the secret. NOTE. At about six inches from the fixed deck, and supported by cross beams, it will be necessary to raise an artificial one of thin planks, under which must be previously placed a number of small iron boxes, open at the top, and filled with powder, connected with each other by a train. The instant this is fired, the upper, or false deck, will blow up _en masse_, without affecting in the slightest degree the permanent deck beneath. No. XIV. How to bring a force to weigh up an anchor, or to do any forcible exploit in the narrowest or lowest room in any ship, where few hands shall do the work of many; and many hands applicable to the same force, some standing, others sitting, and, by virtue of their several helps, a great force augmented in little room, as effectual as if there were sufficient space to go about with an axle-tree, and work far from the centre. NOTE. The application of an endless screw, or worm, appears the most advantageous mode of increasing power in a small space; and it possesses the additional advantage of remaining stationary at any point without the assistance of the ratchet and click. No. XV. A way how to make a boat work itself against wind and tide, yea, both without the help of man or beast; yet so, that the wind or tide, though directly opposite, shall force the ship or boat against itself; and in no point of the compass, but it shall be as effectual as if the wind were in the poop, or the stream actually with the course it is to steer, according to which the oars shall row, and necessary motions work and move towards the desired port, or point of the compass. NOTE.