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THE POPULAR SCIENCE MONTHLY 



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 combina- 

 tion of drawing and twisting, with an excess of drawing ; while 



worsted spinning is 

 a combination of 

 the same processes, 

 with an excess of 

 twisting. 



The spinning- 

 frame, originally 

 used in the worst- 

 ed manufacture, is 

 very different from 

 the mule, the roving 

 having been sub- 

 jected, as we have 

 seen, to * processes 

 not recpiired in deal- 

 ing with the con- 

 densed sliver. In 

 the worsted spin- 

 ning-f rame,or thros- 

 tle, the rollers are so 

 arranged as to draw 

 out the roving be- 

 fore any twist is im- 

 parted. 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, involv- 

 ing a different preparation of the roving, which is simply the 

 principle of mule-spinning, already described. A flier-spindle is 

 shown in the illustration.* 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 in- 

 vented 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 



Fig. 17. Flier-spindle. 



