Hammock. [From Sp. hamaca, a kind of hanging bed or mat. Columbus, in the narrative of his first voyage, says: "A great many Indians in canoes came to the ship to-day for the purpose of bartering their cotton, and hamacas or nets in which they sleep] Hammocks used at sea, especially in men-of-war, are made of canvas, and have a number of cords at each end called clues, which are brought together and secured to an iron ring, which is hung on a hook attached to the deck beams. Those used in tropical parts of America and in the North in the summer time are made of hemp or Panama grass. Hammocks may be made water-proof by immersing in boiling linseed oil, and leaving them in it a day or two. When taken out the superfluous oil should be rubbed off with a cloth, and allowed to dry. They will then not become rotted by the action of the weather.