WHALEBONE. The baleen-plates which take the place of teeth in the mouths of the baleen whales (see Whale) constitute the whalebone of commerce. They vary in length from a few inches up to 10, and even in rare instances 12 feet. Chemically they consist of albumen hardened by a small proportion of phosphate of lime. Their color is usually of a bluish black, but in some species they are striped longitudinally with bands of a whitish color; and they terminate at the point in a number of coarse black fibres of the baleen, which fibres are also found more or less down both sides of the blade. These fibres are used by brush-makers. Whalebone before being fit for use is first trimmed—that is, all the hairs are removed from the point and edges of each blade; and generally the surface of each flat side is scraped. The blades are then boiled in water or heated in steam for several hours, until they become soft enough to be cut with a common knife. The workman then cuts them into lengths fitted for the purposes to which they are to be applied. They were formerly extensively used in thin strips, such as stay-bones and umbrella-ribs, but within recent years steel rods have been largely substituted in these manufactures.