any heavy matter, as stone, gravel, or iron, thrown into the hold of a ship, in order to make her sink a proper depth in the water, that she may be capable of carrying a sufficient quantity of sail without upsetting. To ballast a ship properly, the materials should be so disposed that she may be duly poised, and maintain a proper equilibrium on the water, without either being too stiff or too crank, which are conditions equally pernicious. Stiffness, in ballasting, is occasioned by disposing a great quantity of heavy ballast, as lead or iron, in the hold, which naturally places the centre of gravity very near the keel; and that being the centre about which the vibrations are made, the lower it is placed, the more violent will be the motion of rolling. Crankness, on the other hand, is occasioned by having too little ballast, or by disposing the ship's lading so as to raise the centre of gravity too high, which also endangers the mast when it blows hard. For, when the masts are deflected from the perpendicular, they strain on the shrouds in the nature of a lever, which increases as the sine of their obliquity.

Ships are said to be in ballast when they have no other loading. Masters of vessels are obliged to declare the quantity of ballast they bear, and to unload it at certain places. They are prohibited unloading their ballast in havens, roadsteads, &c., the neglect of which prohibition has ruined many excellent ports.