COTTON-SPINNING 981 



we suppose the spindles and bobbins (both of which have independent motions) to 

 revolve simultaneously and in the same direction, their operation will be as follows : 

 The sliver properly drawn by the fluted rollers, enters the opening of the funnels, pro- 

 ceeds thence downwards through the hole in the arm of the fork, runs along its tube u, s, 

 aiid then winds round the bobbin. This path is marked in fig. 568 by a dotted line. 



The revolution of the spindles in the above circumstances twists the sliver into a 

 soft cord ; and the flyer , t, or particularly its tubular arm s, lays this cord upon 

 the bobbin. Were the speed of the bobbins equal to that of the spindles, did the 

 bobbin and spindle make the same number of turns in the same time, the process 

 would be limited to mere twisting. But the bobbin makes in a given time a some- 

 what greater number of revolutions than the spindle, and thus the cord is wound upon 

 it. Suppose the bobbin to make 40 revolutions, while the spindles make only 30 ; 30 

 of these revolutions of the bobbin will be inoperative towards the winding-on, because 

 the flyers follow at that rate, so that the cord or twisted sliver will only be coiled 10 

 times round the bobbin, and the result as to the winding-on will be the same as if the 

 spindle had stood still, and the bobbin had made 40 30 = 1 turns. The 30 turns of 

 the spindles serve, therefore, merely the purpose of communicating twist. 



Simple as the winding-on process may seem, a little reflection will show that there 

 are complications involved in it which do not at first sight appear. It must be 

 observed, in the first place, that as the cord is wound on the bobbin, the diameter 

 of the latter increases with every succeeding layer of cord put upon it, and the length 

 taken up by each turn becomes continually greater. It is, therefore, necessary so to 

 reduce the number of revolutions of the bobbin as that they may not stretch nor break 

 the cord by taking it up faster than it is delivered from the fluted rollers. A second 

 point to be noticed is, that in order to secure a proper distribution of the cord upon 

 the bobbin, and the regular increase of its diameter, two of its successive convolutions 

 should not be applied over each other, but that they should be laid close side by side. 

 This object is attained by the slowly ascending and descending motion of the bobbin 

 upon the spindle. This up-and-down motion must become progressively slower, since 

 it increases the diameter of the bobbin at each range by a quantity equal to the dia- 

 meter of the sliver. What has now been stated generally will become more intelligible 

 by an example. 



Let it be assumed that the drawing rollers deliver, in 10 seconds, 45 inches of 

 roving, and that this length receives 30 twists. The spindles must, in consequence, 

 make 30 revolutions in 10 seconds, and the bobbins must turn with such speed, that 

 they wind up the 45 inches in 10 seconds. The diameter of the bobbin barrels being 

 1-J inch, their circumference of course 4 inches, they must make 10 revolutions 

 more in the same time than the spindles. The effective speed of the bobbins will be 

 thus 30 + 10=40 turns in 10 seconds. Should the bobbins increase to 3 inches 

 diameter, by the winding-on of the sliver, they will take up 9 inches at each turn, and 

 consequently 45 inches in 5 turns. Their speed should therefore be reduced to 

 30 + 5 = 35 turns in 10 seconds. In general, the excess in number of revolutions 

 which the bobbins must make over the spindles is inversely as the diameter of the 

 bobbins. The speed of the bobbins must remain uniform during the period of one 

 ascent or descent upon their spindle, and must diminish at the instant of changing the 

 direction of the up-and-down motion ; because a fresh range of convolutions then 

 begins with a greater diameter. 



The motions of the drawing rollers, the spindles, and bobbins are produced in the 

 following manner : A shaft c, figs. 565 and 566, extending the whole length of the 

 machine, and mounted with a fly-wheel d', is set in motion by a band from the running 

 pulley upon the shaft of the mill, which actuates the pulley of. b' is the loose pulley 

 upon which the band is shifted when the machine is set at rest. Within the pulley a', 

 but on the outside of the frame, the shaft d carries a toothed wheel b 1 , which by means 

 of the intermediate wheel c 2 turns the wheel d 2 upon the prolonged shaft of the back- 

 most fluted roller (m 2 , fig. 566). This wheel, d 1 , may be changed for one with a 

 greater or less number of teeth when the cotton is to receive more or less twist ; for 

 as the spindles revolve with uniform velocity, they communicate the more torsion the 

 less length of sliver is delivered by the rollers in a given time. Upon the same shaft 

 with d 1 , a pinion, e 2 , is fixed, which works in a wheel, y 2 . Within the frame another 

 changeable toothed wheel, or ' change pinion ' g 1 , is made fast to the shaft of/ 2 . This 

 pinion regulates the drawing, and thereby the fineness or number of the roving. It 

 works in a wheel, A 2 , upon the end of the backmost fluted roller a, fig. 566. The 

 other extremity of the same roller, or, properly speaking, line of holder and the pulley 

 is sufficient to distend the endless band n', which runs from the cone K, through under 

 the pulley I', and round the small drum m! on the shaft s 2 . A pulley or whorl C with 

 four grooves, is made fast by means of a tube to this shaft, and slides along it back- 

 wards and forwards, without ever ceasing to follow its revolutions. The shaft pos- 



