Cleaning a ship's bottom by burning off the grass, ooze, shells, or sea-weed, which it has contracted by lying long in harbour; it is performed by holding kindled furze, faggots, or reeds to the bottom, which, by melting the pitch that formerly covered it, loosens whatever filth may have adhered to the planks; the bottom is then covered anew with a composition of sulphur, tallow, &c., which not only makes it smooth and slippery, so as to divide the fluid more readily, but also poisons and destroys those worms which eat through the planks in the course of a voyage. This operation may be performed either by laying the ship aground after the tide has ebbed from her or by docking or careening.