This section is from the "A Complete Dictionary of Dry Goods" book, by George S. Cole. Also available from Amazon: A complete dictionary of dry goods and history of silk, cotton, linen, wool and other fibrous substances,: Including a full explanation of the modern processes ... together with various useful tables.
Woolens. There are two great classes of manufacturers in this country each employed in using the same raw material - the fiber from sheep: still they are in many respects unlike each other. The products of the factories in which carded wool is employed are termed "woolen" fabrics; those in which combed wool is used are termed "worsted" fabrics. The fundamental distinction between the two classes of the fabrics is the way the yarn for each is spun. Yarn for woolen cloth is very slightly twisted, so as to leave the fibers as free as possible for the fulling process, and the fibers are crossed and interlocked in every direction. Worsted, on the the other hand, is fiber prepared by combing, and requires the long hairs to be laid parallel with each other, being hard spun and made into a much stronger thread, thereby producing a yarn quite unlike the woolen yarns. Names are given to various kinds of woolen cloths according to the way they are finished, the special material of which they are made, and the purposes for which they are intended. Broadcloth, melton, kersey, cassi-mere, tweed, ladies' cloth, flannel, blankets, cheviot, and doeskin are representative woolens. In order to illustrate the difference between a worsted and a woolen fabric of exactly the same weave, compare the character and properties of a fine doeskin with those of a fine corkscrew worsted: the qualities of luster, softness of handle, and fineness of texture are common to both these fabrics; but however carefully the doeskin may be examined, the crossings of the warp and weft will be found to be completely hid from view, causing the cloth to appear more like the result of felting wool than of interlacing individual threads of warp and weft with each other. On taking up the corkscrew worsted, although the threads may not be followed without the aid of a magnifying glass, yet it is clear to the casual examiner that its leading feature (the "corkscrew") is obtained by the mode of interlacing the threads. This leads to an important conclusion, namely, that the soft, pliable and mellow condition, or rather structure, of a woolen thread make it capable of taking a different finish to that of worsted, while the latter is more suitable to fabrics where the weave is intended to be the most prominent feature of the pattern. The well defined surface of the worsted thread fully develops the effect of woven pattern, and hence the larger variety to weave effects seen in the worsted fabrics for both ladies' and gentlemen's wear. The soft and pliable nature of woolen yarns fit them especially for napping, or in which the finish is to form the main feature of the completed fabric.