supporting the extremities of the ship, which have so little bearing below to give them the necessary support from the water. The bows and stern generally sink one or two inches on launching, and continue to do so as long as the ship is afloat. A curvature in the keel, such as that in the 'America,' would also tend to prevent hogging. It is a matter of importance to have the gunwale no higher out of water than is necessary to prevent the decks being drowned, because every inch of it tends to impede her way on a wind, and to send her to leeward. When a sea meets her bows, it first rises considerably above the load-water-line ; but as it passes along, the vessel is heaved up over it, and the stern again sinks into it. Hence the wave, when amidships, is not much higher than the load-water-line, and the deck ought, therefore, not to be very much above that. The stern need not be so high as the bows if it be broad. CHAPTER II. THE dividing-line, which we have taken as our guide in forming the body of the vessel, has been described by the batten through the three given points. No particular curve has been assigned to it. Its projections in the sheer and half-breadth plans have been curves, which the batten naturally assumed. It is necessary, therefore, to ascertain by experiment, what sort of curve, of single or double curvature, should be given to the dividinglines; or what kind of curve, of simple curvature, its projections in the sheer and half-breadth plans, should assume. If experiments be made by drawing bodies of certain shapes through the water, noticing both the rates at which they travel respectively, and the weights required to move them, we shall learn which body offers least resistance to the water; and by ascertaining its dividing-lines, we shall know supporting the extremities of the shi so little bearing below to give them support from the water. The bo generally sink one or two inches on! continue to do so as long as the A curvature in the keel, such as 'America,' would also tend to prever It is a matter of importance to ha no higher out of water than is neces the decks being drowned, because tends to impede her way on a wi her to leeward. When a sea mee first rises considerably above the but as it passes along, the vessel is it, and the stern again sinks into wave, when amidships, is not mɩ the load-water-line, and the deck not to be very much above that. not be so high as the bows if it be that applied to BCD. ertained from numerous relocities, a blunt bowresistance in nearly the velocities. And as the untness of the bow has › resistance. ved through the water at ; and it was found that flat bow-end,) obtained, ice, more velocity than of six feet below, provided But at a high velocity, re velocity at the surface (with the sharp bow-end) ity, when moved close below id when sunk to a depth of velocity was not great. But igh velocity, its speed at the more than below. bears that, for a high velocity, it D what form a dividing-line should have, and where its greatest breadth should be. And if these bodies are so formed as to have: 1. Two horizontal planes for their upper and under surfaces, and vertical superfices for their sides; then the dividing-lines will be all the same, and of the same form as the water-line. 2. If the sides are vertical planes, parallel to the line of motion, and the under side is a superficies, such, that its intersections with planes perpendicular to the line of motion shall be horizontal lines, then the dividing-lines will be all similar and in vertical planes. 3. If the body be a solid of revolution, the dividing-lines will all be similar, and the same as the water-line. Numbers of experiments have been made, and it is thence ascertained that, if there be taken two cuniform bodies, ABDC, B and BCD, of which the D C D C part, BCD, the same as the smaller body, with another part, ABC, of which the upper and under surface is an equilateral triangle; and if the bodies are moved through the water with the end D aftermost; and (1) if the bodies are moved slowly, then the body, AD, |