The yarn is now a finished product. It may be sold by the spinner to the weaver or it may be woven in the mill in which it is spun. Before it is ready for the loom, however, there are a number of operations which must be completed. The yarn from the ring frame, or mule, is wound in a large cop, or on a bobbin. It must be put upon spools before it can be warped. The spooler is a simple machine, but one that requires constant attendance. In the spooler, bobbins are placed upon holders or spindles, and the thread is passed over a series of guides to the spool, up above. The spool revolves at a high rate of speed, and the thread is wound evenly upon it. The operator must watch for broken threads, retie them, replace the empty bobbins by full ones and see that the empty ones are gathered up uninjured. She--the operator is usually a girl or woman--must be alert and active, and especially nimble fingered. [Illustration: _"Close-up" of Ring Spindle in American mill_] One of the most important inventions, one that was received with acclaim by the American manufacturer, and one which actually reduced his labor cost on spooling no less than ten per cent. at one clip, is a tiny little thing that is held in the palm of the hand. This is the Barber knotter. When a thread breaks, the attendant places the two ends together in the machine and by the mere pressure of her thumb ties the knot much better than she could do it without the knotter. The economies which it effects extend beyond the mere spooling, for better knots mean fewer breaks in the warping process, and a better cloth at the end of weaving. The spools from the spooler are placed on a large frame, called a creel. The creels have an average capacity of about 600 spools, and there are usually 16 to 20 in one tier. The threads from the spools are drawn between the dents of an adjustable reed, then under and over a series of rollers. From here they are led down to the beam, upon which they are wound. The revolving of the beam unwinds the yarn from the spools and winds it regularly and evenly upon the beam itself. There is a device for measuring the length of the warp wound, and stop motions for arresting the operation should a thread break or other accident occur. [Illustration: _Each operator at these spoolers has a Barber knotter on her hand_] The yarn of the warp must usually be impregnated with a sizing which will smooth out and stick down its furry surface and add as well to the tensile strength so that the strain of weaving may be withstood. For this the most effective and most generally used machine is the slasher, the chief feature of which is a roller, whose lower side is immersed in the sizing solution. Threads from the warp beam are run around this roller through the solution and then dried, after which it is finally wound on another beam for the loom. A considerable number of loom beams can be filled from one set of the warper beams mounted in the slasher.