e of speed; so
quickly indeed, that there is no other body used in spinning which
approaches it for speed.

It is quite a usual practice to have them making about 8000 revolutions
per minute, and sometimes a speed of 10,000 is attained by them.

Assuming that a "Cop" of yarn (see Fig. 27), showing the cops on the
spindles, has been partly made upon each spindle, the roving or thread
from the rollers would extend down to the cop and be coiled round the
spindle upwards up to the apex. The spindle would probably twist the
thread for 40's counts twenty-three or twenty-four times for each inch
that issued from the rollers, there being a well-recognised scale of
"twists per inch" for various sorts and degrees of fineness of yarn.

Unlike the bobbin and fly frames, the roving or yarn is not wound on its
cop or spindle as it is delivered, but a certain definite and regulated
length of cotton is given out to each spindle, and fully twisted and
attenuated before it is wound into a suitable shape for transit and for
subsequent treatment.

To keep each thread in tension, therefore, as it is delivered from the
rollers, the carriage containing the twisting spindles is made to recede
quickly away from the rollers, a common distance for such movement being
64 inches. All the time the spindles are quickly revolving and putting
twist into the rovings, thus imparting strength to them to a far greater
degree than at any previous stage. Often the carriage is made to recede
from the rollers a little quicker than the latter, the difference in the
surface speeds between the two being technically known as "_gain_." The
object of this carriage "gain" is to improve the "evenness" of the yarn
by drawing out any thick soft places there may be in the length of
thread between each spindle and the roller, a distance of 64 inches. It
is a property of the twist that it will run much more readily into the
thinner portions of thread than the thicker, thus leaving the latter
capable of stretching out without breaking.

Arrived at the limit of 64 inches stretch (see Fig. 27), certain rods,
levers, wheels and springs are so actuated that the parts which draw out
the carriage and cause the rollers to revolve are disconnected, so that
both are brought to a standstill for the moment.

In many cases the spindles at this stage are kept on revolving in order
to put in any twist that may be lacking in any portion of the stretch.

Twisting being finished, the