Slender filaments issuing out of the pores of the skins of animals, and serving most of them as a covering. All hair appears round; but the microscope shows them to be of various shapes, as square, triangular, hexan-gular, etc. The human hair forms a considerable article of commerce, princi pally for the manufacture of perukes. The hair of northern countries is preferred on account of its greater strength and length. Hair is sometimes leached on the grass like linen, after previous washing and steeping in a bleaching liquid; it may then be dyed of any colour. When it does not curl naturally, it is made to do so by first boiling it and then baking it in an oven.
M. Vanquelin, who investigated the chemical constituents of hair, found that red hair differs from black only in containing a red oil instead of a blackish green oil; and that white hair differs from both these only in the oil being nearly colourless, and in containing phosphate of magnesia, which is not found in them. Hair is usually distinguished into various kinds; the stiffest and strongest, such as those on the back of swine, are called bristles. The soft and pliable, like that on sheep, is called wool; and the finest of all is called down. Hair is also woven into cloth (of which it forms only the weft) for covering the seats of chairs and sofas, besides other purposes.