"My readers are sure to know that all woven fabrics consist of two distinct parts, the woof and the warp. The woof is that which is passed by the shuttle from one side of the loom to the other, and which is enchased between the two surfaces formed by the warp. As the woof is subjected to more wear and tear than the warp, it should be stouter. For this reason each of the two ends of which it is composed is twisted separately before the two are twisted together, while for the warp the latter of these processes is sufficient. The result of this difference is that, when looked at beneath the microscope, the thread of the woof has an uneven look, as though it were a small cable, while that of the warp looks flat and smooth, and is therefore adapted to reflect the light, receiving the shiny look which makes a silk-stuff so attractive. "But the beauty of these fabrics depends, above all else, upon the way in which the silk is divided as it is drawn from the cocoon. This first stage of the spinning is performed in one or other of three ways, according to the kind of wheel which is employed for it. The method which the Spaniards have adopted from an early period has the following drawback; that the small threads of six, seven, and eight cocoons which are stripped at the same time, go to form a single thread, and are deposited upon a small spindle without the thread rubbing against another one, which friction serves to lay the little hairs which bristle up, so that the slip of silk thus formed retains a hairy nap and is easily frayed. In the Piedmontese method, on the other hand, each slip is joined to another, and is not drawn apart until it has been twisted round it four or five times. "The third method, known as that of Vaucanson, is more expensive than the one last mentioned. In the wheel invented by Vaucanson, the two silk-slips are reunited after the first twisting, in order to be twisted once again. This operation is called the 'double _croissade_.' "If these threads, thus placed on bobbins, are intended for the woof, they are enchased perpendicularly in a machine consisting of several compartments, in which they are twisted separately. Thence they are transferred to another machine, in which they are twisted all together; after which they are ready for the loom. Those which are destined for the web are not twisted (as I have explained above) until the moment when they are united. Both at Valencia and at Talavera de la Reina these machines, so precious to the weaver's craft, and which economise manual toil, are not unknown.[20]