rn equally on
every part of the spool barrel, and the requisite drag resulted from
friction set up by the thread rubbing against the surface of the cup.
The throstle has almost disappeared from the cotton industry, and
Danforth's cap frame entirely so, but the latter is still used to spin
worsted.

_Ring spinning_ is practically the only system of continuous spinning
used in the cotton industry; it was first patented in the United
States of America by J. Thorpe, in 1828, and in that country was
extensively used long before it became established in England. Its
chief feature consists in the substitution for the flyer, or the cap,
of a smooth annular ring (A, fig. 8) formed with a flange at the upper
edge, over which a light C-shaped piece of wire (B), called a
traveller, is sprung. The rings are secured in a rail (C) that rises
quickly and falls slowly, but at each succeeding ascent and descent it
attains a higher point than that previously reached. A spindle (D) is
supported by, and turns in a bolster secured to a fixed rail (E). If
the bolster only provides a bearing for the centre of the spindle, and
so leaves the foot free to find its own position of steadiness, it is
known as a self-balancing or gravity spindle. A recess in the bolster
is filled with oil to automatically lubricate the bearing. A spindle
is placed in the centre of each ring; it has a sleeve fitted upon it
which carries a wharve (F) that covers the upper part of the bolster,
and a band from a pair of drums is drawn round the wharve to drive the
spindle. So perfect is the construction of these spindles that they
can be run without appreciable vibration at speeds far beyond the
ability of operatives to attend them; although a speed of 11,000
revolutions per minute is a practicable one. After passing the drawing
rollers (G), the roving (H) is twisted, hooked into the traveller (B),
and made fast to a spool (I) placed upon the spindle. As spinning
proceeds the traveller is pulled round the ring by the thread; it thus
puts a drag upon, and holds the thread at the winding point. In all
continuous spinning the number of twists inserted into a given length
of thread is governed by the surface speed of the front roller,
relatively to the revolutions of the flyer, or to the speed of the
winding surface.

[Illustration: FIG. 8.]

_Intermittent Spinning_.--The essential difference betwee