"The best way for you to learn would be for you to spill some of that water you have got in your kettle on the deck." Frank, without stopping to think, tipped up his kettle, and turned out some of the water; and the man, who had been watching his every movement, sprang toward him and threw down the swab, exclaiming, "I've caught you, my hearty; now you may log this bit of rope for awhile." "What do you mean?" inquired Frank, amid a roar of laughter from every sailor who had witnessed the performance. "What does he mean?" repeated the mate; "why, he means that you have got to wipe up that water you have spilt on deck, and carry that swab until you can catch some one else doing the same thing." For the benefit of the uninitiated, we will make an explanation. It often happens on shipboard, especially receiving-ships, that the men become very careless; and in carrying water, paint, or grease about the ship, frequently spill some of it on deck. While this state of things continues, it is impossible to keep a ship clean, and, in order to break up this habit, the culprits are obliged to wipe up whatever they have spilled, and then carry a swab about the deck until they can detect some one else equally unfortunate. This is not a pleasant task; for, as soon as this rule is put in force, the men become very careful, and the luckless offender is sometimes obliged to walk the decks the entire day before he can detect any one in the act of violating it. Frank, of course, did not understand this, and the mate had got him into the scrape for the purpose of getting the man who first had the swab, who was a particular friend of his, out of his unpleasant position. "Come, youngster, drop that mess-kettle and pick up that swab," commanded the mate. Frank knew he had no alternative; so he set his mess-kettle on deck out of the way, and picking up the swab, walked aft to the place where he had left Simpson. "Hullo, there," exclaimed the latter, as Frank approached, "what's the matter with you?" Frank related the whole circumstance, and Simpson could scarcely restrain his indignation. "That bo'son's mate ought to be mast-headed for a whole week," he exclaimed. "But I'll square yards with him some day. I'm sorry you have got into this scrape, but it can't be helped. I've seen many a good fellow, in my time, in the same fix. Now you must walk around the ship, and if you see any one spill the least drop of water, or any thing else, on deck, rush up and give him the swab. There are a good many landlubbers on board, who don't know the rules, and you won't have any trouble in catching them. Always be careful to keep the swab behind you, out of sight."