COTTON MANUFACTURE. 89 
of the levers, 0,0 (fig. 7). These levers receive their motion from the heart- 
formed cam, Pp, upon a shaft with the wheel, xr, which is driven by a pinion 
upon the shaft, s, and a worm, 1, on the shaft of the wheel, 5. The whorls, 
bb, make about 6,000 revolutions in a minute. To prevent the interference 
of the threads with each other at this great speed, the bobbins are sometimes 
separated from each otber by partitions of tin plate secured to a board back 
of them. 
5. Taz Morr, anp Mute Spinnine. 
The finer qualities of thread are spun upon the mule. The operation of 
the machine is in general similar to that of the stretching frame, and may 
be stated as follows : | 
The rovings coming from the bobbins in the creel pass between the rol- 
lers and the spindles, the carriage in this machine moving somewhat faster 
than the rollers, and not as in the stretching frame, where they move with 
equal velocities. This excess of velocity is called the gain of the carriage, 
and has the effect of rendering the thread uniform by drawing out the larger 
and less twisted portions. When the carriage has advanced 45 or 50 inches, 
according to the fineness of the work, a general change takes place in the 
operation of the mule; the drawing rollers stop, the velocity of the spindles 
is nearly doubled, and the carriage slackens its pace to about one sixth of 
its former velocity; this part of the operation is called draw. When the 
threads are sufficiently extended the carriage stops, but the spindles con- 
tinue to revolve until the requisite twist is communicated. The thread is 
then wound upon the spindles, as the carriage returns to repeat the opera- 
tion. 
Pl. 18, fig. 8, is an end view of a self-acting mule, or mule jenny ; jig 9, 
a plan of the head-stock, showing a portion of the drawing-rollers, certain 
portions of the head-stock being removed, which are shown in jig. 10; 
jig. 11 is a cross-section, fig. 12 a front view of a portion of the carriage 
which moves beneath the head-stock; jig. 18, the frame opposite to the 
head-stock ; and jigs. 14 and 15 are detached portions, to which reference 
will be made. 
AAA (fig. 8) is a cast-iron frame, to which, on each side of the head- 
stock, is fixed the roller-beam 8, seen in section. co’ co’ (figs. 8 and 10) are 
three pulleys upon a horizontal shaft, a. The pulley c, secured together 
with the wheel 7 upon a hollow axle, turns freely upon the shaft; c’, on the 
contrary, is secured to the shaft, and the narrow pulley c” is the loose 
pulley. 
Two bands, p and p’, drive these pulleys; the first moves the pulleys by 
covering one half of each, but it is moved at a certain stage of the process 
upon c alone. At the same time the band p’, running in a contrary direc- 
tion and with a less velocity, runs for a few seconds on the pulley o’ and 
immediately returns to the loose pulley c’. The pulley c, which revolves 
constantly with a uniform velocity, drives the apparatus for changing the 
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