In time of tempests, when all hands are called to save ship, they issue forth into the gale, like the mysterious old men of Paris, during the massacre of the Three Days of September: every one marvels who they are, and whence they come; they disappear as mysteriously; and are seen no more, until another general commotion.
Such are the principal divisions into which a man-of-war's crew is divided; but the inferior allotments of duties are endless, and would require a German commentator to chronicle.
We say nothing here of Boatswain's mates, Gunner's mates, Carpenter's mates, Sail-maker's mates, Armorer's mates, Master-at-Arms, Ship's corporals, Cockswains, Quarter-masters, Quarter-gunners, Captains of the Forecastle, Captains of the Fore-top, Captains of the Main-top, Captains of the Mizen-top, Captains of the After-Guard, Captains of the Main-Hold, Captains of the Fore-Hold, Captains of the Head, Coopers, Painters, Tinkers, Commodore's Steward, Captain's Steward, Ward-Room Steward, Steerage Steward, Commodore's cook, Captain's cook, Officers' cook, Cooks of the range, Mess-cooks, hammock-boys, messenger boys, cot-boys, loblolly-boys and numberless others, whose functions are fixed and peculiar.
It is from this endless subdivision of duties in a man-of-war, that, upon first entering one, a sailor has need of a good memory, and the more of an arithmetician he is, the better.
White-Jacket, for one, was a long time rapt in calculations, concerning the various "numbers" allotted him by the _First Luff_, otherwise known as the First Lieutenant.

In the first place, White-Jacket was given the _number of his mess_; then, his _ship's number_, or the number to which he must answer when the watch-roll is called; then, the number of his hammock; then, the number of the gun to which he was assigned; besides a variety of other numbers; all of which would have taken Jedediah Buxton himself some time to arrange in battalions, previous to adding up.

All these numbers, moreover, must be well remembered, or woe betide you.
Consider, now, a sailor altogether unused to the tumult of a man-of-war, for the first time stepping on board, and given all these numbers to recollect.

Already, before hearing them, his head is half stunned with the unaccustomed sounds ringing in his ears; which ears seem to him like belfries full of tocsins.

On the gun-deck, a thousand scythed chariots seem passing; he hears the tread of armed marines; the clash of cutlasses and curses.