The lengthwise threads of a fabric are called the warp. The crosswise threads are called the weft or filling. To make cloth, the warp and weft must be interlaced with each other in a suitable manner. The operation is called weaving, the machine in which it is performed is, of course, the loom. The principal operations of weaving are as follows: 1. Shedding, or the raising and lowering of the alternate threads of the warp, so that the weft may pass under and over them. This is done by means of the harnesses and their heddles. 2. Picking, or placing a thread of the weft between the warp threads so raised and lowered by means of the shuttle. 3. Beating-up, or pushing, each thread of the weft into its position close against the thread which has preceded it by means of the reed. 4. Letting-off, or permitting the warp to unwind from the beam only just as fast as is needed by the speed of the weaving. This is accomplished by friction bands and weights on the warp beam. 5. Taking-up, or winding upon a roller the cloth as it is manufactured. In addition to these primary operations, the loom has attachments for performing several other functions, such as stop-motions for stopping the loom when warp or filling threads break, or when the shuttle fails to cross the loom completely; temples for holding out the cloth laterally as the weaving proceeds; a mechanism--in the most modern looms--for changing the shuttles, or the cops in the shuttles, as the weft thread on the cops becomes exhausted, etc. [Illustration: _Diagram of ring spindle_] The modern cotton loom, which automatically removes the filling bobbins without stopping the loom, is rapidly displacing the older types, and one weaver can now attend to a surprisingly large number of looms, being greatly assisted also by the automatic warp and filling "stop motions." CHAPTER IX The Finishing Operations Following the manufacture of the cloth, come the operations necessary to prepare it for the market. These involve such treatments as bleaching, printing, mercerizing, dyeing, and finishing (in the narrow sense). The number of machines involved in these various processes rivals the number which are used in the actual spinning and weaving operations. Modern bleaching is a highly technical science, conceived and planned by engineers, and carried out with elaborate machinery by skilled workers.