Felt

a fabric formed of wool, hair, or fur, by matting the fibers together under the influence of heat, moisture, and pressure. The invention of felt is ascribed by tradition to St. Clement. It is said that he put carded wool in his sandals to keep his feet warm. He found that the warmth, moisture, and pressure of his feet felted the wool into something resembling cloth. In Roman Catholic countries the hatters celebrate St. Clement's day on the 23d of November in honor of his discovery. As a matter of fact felt was known long before St. Clement's time. It is thought that the first cloth ever made was a species of felt. It was probably produced by treading under the bare feet the wool of sheep and the hair of goats. It is said that the Turkomans of Central Asia still employ this method to produce a coarse felt with which they cover their movable huts. The Roman Pliny says that the ancient Gauls made a felt so firm and strong that a sword could not cut through it, and adds that they employed vinegar in its manufacture. Felt was known to the Greeks in Homeric times; its manufacture is supposed to have been introduced into western Europe during the Crusades.

Since the invention of the microscope made possible the examination of the structure of wool fiber a much more perfect felt has been produced. Previous to this invention the real cause of felting was unknown. Consequently the method employed in the manufacture was far from scientific. The microscope revealed the fact that nearly all animal fibers are covered with minute scales or hooks pointing in one direction and overlapping each other, as do the scales of a fish. These scales have been counted successfully. No animal fiber has less than 1,000 to the inch, and some reveal as many as 2,400 to the inch. When hair or wool is worked, rolled, and pressed, these tiny scales or teeth catch into and hold each other fast. If subjected to alternate baths of hot and cold water the fibers shrink within themselves, which adds to the action of the scales in making a firm mat. Wool fiber is naturally wavy or crinkled, and this form is an advantage in helping the fibers to become closely interlaced with each other. Cotton and other vegetable fibers are smooth and straight. They cannot be felted, although occasionally small quantities are used in admixture with animal fibers.

The manufacture of felt is the simplest process used in producing fabrics of any sort. As short fibers and many "waste" products may be used, common felt is usually quite inexpensive. For special purposes, however, high grade raw materials are employed. In the making of felt for hats the best of fur is chosen.

In making felt the fiber is carded into fine, gossamer-like sheets, the size of the finished web. These are laid one on top of another. The finest fiber is reserved for the top layer. If several grades are used the secret of success lies largely in distributing the better grades properly through the mass. This is the only part of the operation which requires skill and judgment. The other processes are entirely mechanical. The pile of fluffy sheets of wool is pressed between heavy rollers. Sometimes the rollers are heated with steam. Sometimes the felt is immersed in hot water. An oscillating motion is given to the rollers, which aids in the contracting and matting of the fiber. After a few hours in the machine, a sheet of strong, compact felt is the result. In making light weight felt several layers are pressed at one time, an "apron" being laid between each two layers. After leaving the press the fabric is fulled, dyed, and pressed. Fine qualities are napped, brushed, and sheared, as are woven goods, to produce a smooth surface.

Felt of various grades is in use for a vast number of purposes. It is employed in the manufacture of boots and shoes, in the manufacture of boots and shoes, in the rubber and saddlery trade; for packing engines, deadening sounds, in making refrigerators, for carpets, rugs, and table covers, for linings, trimmings, mittens, and gloves. Men's, women's, and children's hats of every variety and quality of felt are produced in large numbers. Felt is of greater importance, probably, in this line than in any other industry.