excelling in the manufacture of very fine counts, to which their system of worsted mule-spinning seems to be especially adapted. The finer yarns spun in America will usually average about 40s, which involves a length of more than 20,000 yards to a pound of yarn.
From the drawing machines, the material next advances to the roving frame, the last operation through which the sliver—called "stubbing" at this stage of manipulation—must pass before it is ready for spinning. Roving may be described as a combination of drawing and twisting, with an excess of drawing; while 
Fig. 17.—Flier-spindle. worsted spinning is a combination of the same processes, with an excess of twisting.
The spinning-frame, originally used in the worsted manufacture, is very different from the mule, the roving having been subjected, as we have seen, to processes not required in dealing with the condensed sliver. In the worsted spinning-frame, or throstle, the rollers are so arranged as to draw out the roving before any twist is imparted. There are three distinct types of worsted spinning-frames in common use, known as the flier, cap, and ring. The French utilize a fourth method, involving a different preparation of the roving, which is simply the principle of mule-spinning, already described. A flier-spindle is shown in the illustration.[1] It is most commonly used for the
- ↑ It is quite clear that the flier, which is fitted around modern spindles for twisting the yarn before it is wound on the bobbin, was known to Leonardo da Vinci, and probably invented by him. Among his mechanical drawings is one which shows a spindle, with flier and bobbin, with a device for moving the bobbin up and down on the spindle so as to effect
