distributed over the full range between the ends or flanges.

Each spindle is driven separately by means of a tape or band which
passes partially round the driving cylinder and the driven whorl of
the spindle, and a constant relation obtains between the delivery of
the yarn and the speed of the spindle during the operation of
spinning any fixed count or type of yarn. In this connection, the
parts resemble those in the roving frame, but from this point the
functions of the two frames differ. The yarn has certainly to be
wound upon the bobbin and at the same rate as it is delivered from
the drawing or delivery rollers, but in the spinning frame the bobbin,
which rotates on the spindle, is not driven positively, as in the
roving frame, by wheel gearing; each spinning bobbin is actually
driven by the yarn being pulled round by the arm of the flyer and
just sufficient resistance is offered by the pressure or tension of
the "temper band" and weight. The temper band is simply a piece of
leather or hemp twine to which is attached a weight, and the other
end of the leather or twine is attached to the builder rail.

[Illustration: FIG. 21 A LINE OF SPINNING FRAMES]

The front part of the builder rail is provided with grooves into one
of which the temper-band is placed so that the band itself is in
contact with a groove near the base of the bobbin flange. A varying
amount of resistance or tension on the bobbin is required in virtue
of the varying size of the partially-filled bobbin, and this is
obtained by placing the temper-band successively in different groves
in the builder so that it will embrace a gradually increasing arc of
the spinning bobbin, and thus impart a heavier drag or tension.