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.
Flannel. [From Welch gwlanen; in the Middle Ages known as flannella and flannen] Wales appears to have been the home of flannels, and this one fabric has long been the only textile manufactured in that country, while it has been of so much importance there that fairs have been commonly held solely for the exhibition and sale of flannels. The high estimation in which Welch flannels are still held is attributed to the fact that hand labor is much employed in their production. Flannels are woven of "woolen" yarn, but slightly twisted in the spinning, the object being to have the cloth soft and spongy without particular regard to strength. The manufacture is identical with that of other "woolen" goods, their organization being closely allied to that of blankets (which see). The best grades of flannels intended for men's shirts, ladies blouses, etc., commonly known under the term of Cricket flannels, are always shrunk more than the common qualities, because of the numerous cleansing processes they must necessarily undergo after being made into garments. The "shrinking is accomplished by folding a bolt-length of flannel between heavy wet sheets, and letting it remain there 24 hours. The pieces are then hung upon rails to dry in rooms heated by hot pipes. The next process is to fold them in specially prepared papers, which have a very glossy surface. They are then pressed, some mills using hydraulic, others large hand presses, worked by8 or l0 men. The more pressure the more "clothy" they feel. Cheap flannels are never shrunk, because they will not stand it. When being made into wearing apparel by factories they do not even make the acquaintance of the tailor's goose, as they would contract a full "size" or more from the heat. Flannel is recommended by medical men for clothing in both hot and cold countries, from its property of promoting insensible perspiration, which, being absorbed by the spongy material, is immediately distributed equally throughout by the whole thickness of the fabric, and thus being exposed over a large surface is carried off by the atmosphere, keeping the body at the same time at an equal temperature. Like other woolen fabrics, flannels are bleached by the steam of burning sulphur to improve their whiteness. The quality of domestic flannel is denoted by the ounces of weight per square yard. [See Wool, Woolen, Shaker, Canton, Vegetable, Tricot, Outing, Basket, Opera, Flan-nellette, underwear]