ong teeth fastened upon a large cylinder
(A), revolving rapidly, and is flung by centrifugal force against an iron
grid (B) time after time. Sometimes there is a strong current of air
blowing through the tangled mass, helping to loosen the particles. The
dirt comes out through the grid and is carried away, while the lint
itself, after being carried around an indefinite number of times,
gradually works its way along a channel, and finally out between two
large rollers (C), which compress it once more, so that it is, in effect,
a sheet of batting. This sheet, or lap, is rolled up in a large roll (G),
which may be two or three feet in diameter, and is then ready for the
first doubling or blending process. In mills where strength and evenness
of yarn are at a premium, the sheets from three or four laps may be fed
through another opener, usually called a "scutcher," which breaks them
all apart again, mixes up the fibers, cleans out more of the dirt, and
produces a more even lap.

The cotton, as it comes from the opener and the scutcher, is much cleaner
and more attractive. It begins to look like the riches it contains.

[Illustration: _Cross-section diagram of opener_]

To convey the heavy opener-lap from the opener to the carding room, the
more modern mills are doing away rapidly with hand-power, and carry the
lap on a sort of travelling mono-rail conveyor.

The fibers of the lap which comes from the opening room are by no means
parallel, but lie in all directions just as they happened to come from
the grid of the opener. The function of the card is to straighten them,
and at the same time to remove those which are knotted or immature and of
a length below that required for the yarn to be spun, and to take out
practically all of the impurities which may have escaped in the opening
operations.

The principle of carding is one of the oldest of textile mechanical
principles, and all the improvements that have been made have been in
developments rather than in basic ideas. Hargreaves, inventor of the
jenny, and Sir Richard Arkwright both expended their ingenuity upon it,
the latter seeming to have been the first to provide a carding machine
operated by other than hand-power. The basic principle involved is the
straightening out of the fibers by combing or brushing them with wire
brushes or cards.

[Illustration: _"Scutchers" at work_]

In the revolving flat card, which dominates the field today, there are,
as a rule, th