. Two wooden rollers are fixed into
the uprights (see A and B in fig. 170) and in the surface of each of
these a narrow groove is hollowed out lengthwise (see fig. 171); this is
for the purpose of holding a long metal pin, by means of which the
warp-threads are kept in place. The rollers are fitted at one extremity
with a handle for turning them round, and at the other with a ratchet
and toothed wheel to prevent unwinding. The purpose of the upper roller
is to hold the supply of warp-thread and unwind it as required; the
lower one is for winding up the web as the work progresses, so that upon
a loom of this size a piece of work of considerable length can easily be
carried out.

[Illustration: Fig. 172.]

The warp soon after it passes from the top roller is divided into two
leaves by a cylindrical wooden bar about one inch in diameter, called
the cross stave (see fig. 172). The cross stave may be oval or round in
section; if it is oval the warp-threads may be moved more widely apart
when required by turning the stave round, but this is not often
necessary. The upper part of the cross stave can be seen in position in
the loom diagram, which shows also how the stave divides the threads,
which pass alternately one in front and one behind the bar. After this
the threads are passed through a comb-like instrument, having about
fourteen divisions to the inch (see fig. 173). This extends from side to
side of the loom, and lies in a groove made in the bar that fixes the
coat-stave (C in fig. 170) in position at either extremity. It can be
taken out and exchanged for another with a different divisioning, if
necessary; without doing this, however, it is quite possible to put at
intervals two threads through one division, or to pass over one
occasionally if need be. The threads are next fixed in the lower roller.

[Illustration: Fig. 173.]

The coat-stave can be seen projecting from near the top of the loom. A
number of looped threads called coats are fixed to it, and each one of
these encircles a thread of the warp. They are attached only to those
threads that were passed behind the cross stave and form the back leaf
of the warp, and they are for the purpose of pulling these forward when
required.

Underneath the lower roller is fixed a wooden tray, which is useful for
holding bobbins, comb, or scissors.

On the loom is hung a small mirror facing the right side of the work
(see fig. 170). This enables the weaver to glance no