FELT, a kind of stuff resembling coarse cloth, made of hair or wool, without weaving. The fur of the hare, rabbit, seal, beaver, and the wool of the sheep, are the materials chiefly used for making felt. The hairs and loose flocks of wool are thoroughly mixed together by an operation called boning, which depends on the vibrations of an elastic string; when, in consequence of their anatomical structure, they become matted together. This mass, after undergoing pressure to render it firmer, is dipped into a liquor containing a little sulphuric acid; and, when intended to form a hat, it is first moulded into a large conical figure, which is afterwards reduced in its dimensions by working it with the hands. It is afterwards formed into a flat surface, with several concentric folds, which are still further compacted in order to form the brim and the circular part of the crown. It is then forced on a block, which serves as a mould for the cylindrical part of the hat. The nap or outer portion of the fur is afterwards raised by the application of a fine wire brush. The hat is subsequently dyed and stiffened with glue, or with an aqueous solution of shellac. It need scarcely be observed, that these processes are not applicable to the silk hat now in such very general use. See HAT-MAKING. Besides its use in hat-making, felt is much employed to encase the cylinders of steam-engines, and is also rendered waterproof to be applied in the roofing of houses
and many other ways. Attempts have been made to form woollen cloths by a process similar to that of felting, without spinning or weaving; but the cloth made in this way has little strength or durability.