Most ships have a small fire-engine on board, which is not only an admirable safe-guard, but facilitates the washing of decks; an operation that usually takes place once or twice weekly. At such times all the chests are sent below, and all the hammocks hauled upon deck, for the purpose of being aired. Seamen become habitually cleanly in their persons, and in their bedding; but when recruits are on board, they, being less attentive to personal appearance and to comfort, not only breed vermin, but sometimes propagate infectious diseases. Hence, a small quantity of vermin-ointment will perhaps prove an useful succedaneum; its timous application preventing the growth of any colony, of which some stragglers may have laid the foundation. When the decks are washed, it is customary to exercise the seamen in the use of great guns. For this purpose the drum beats to quarters; when all repair to their several stations, and, under the instruction of the several officers, go through the ordinary operations attendant upon that branch of discipline. No persons, of whatever description, females excepted, are exempted from being appointed to some post, where their services may be efficient. The military officers are allotted to commands on the poop, fore-castle, waist, &c.; having under them such cadets and recruits as may be on board; the whole acting as marines. The surgeon, with his mates, those of the sick who are incapable of taking an active part, together with all females, descend to the cock-pit; which, being below the level of the water-line, is tolerably secure from danger; though sometimes a shot, between wind and water, will find its way to that retreat. The crew are always portioned into two watches, except when very numerous; in which case, as well as during the time a vessel is in port, they divide them, including recruits, &c. into three watches. The chief mate commands the starboard-watch; the second mate commands the larboard-watch; and, when there are three, the other, called the mid-watch, is commanded by the third mate. It is customary to relieve the watch every four hours, except in the interval between four and eight o’clock in the evening, which is divided into two reliefs, of two hours each, called ’dog-watches.’ But for the intervention of these, there would be no change in the times of coming upon duty; as each of the starboard and larboard watches would, respectively, come on at the same hours daily; and this would be the same, even if a mid-watch existed: whereas, by dividing the evening-watch, it occasions an odd number, and changes the tour, or series, every day.