cleansed fiber is made up chiefly of the chemical
substance keratin, being similar in composition to horn and feathers. In
burning it gives off a characteristic disagreeable odor. It is a
substance very weakly acid in its nature, for which reason it combines
readily with many dyes. Wool resists the action of acids very well, but
is much harmed by the alkalis, being dissolved completely by a warm
solution of caustic soda. High temperature harms wool.

FLAX

Next to wool and cotton, flax is used most largely in our textile
manufactures. The linen fiber consists of the bast cells of certain
species of flax grown in Europe, Africa, and the United States. All bast
fibers are obtained near the outer surface of the plant stems. The pith
and woody tissues are of no value. The flax plant is an annual and to
obtain the best fibers it must be gathered before it is fully ripe. To
obtain seed from which the best quality of linseed oil can be made it is
usually necessary to sacrifice the quality of the fibers to some extent.

[Illustration: FLAX]

[Sidenote: Treatment of Flax]

Unlike cotton, flax is contaminated by impurities from which it must be
freed before it can be woven into cloth. The first process to which the
freshly pulled flax is submitted is that of "rippling" or the removal of
the seed capsules. Retting, next in order, is the most important
operation. This is done to remove the substances which bind the bast
fibers to each other and to remove the fiber from the central woody
portion of the stem. This consists of steeping the stalks in water.

[Illustration: A FIELD OF FLAX IN MINNESOTA

The Flax Must Be Pulled Up by the Roots to Give Fibres with Tapered Ends.

(Photograph of C. R. Dodge).]

[Sidenote: Retting]

(1) Cold water retting, either running or stagnant water.
(2) Dew retting.
(3) Warm water retting.

[Illustration: RETTING TANK _A_--Inlet; _B_--Undisturbed Water;
_C_--Bundles of Flax.]

Cold water retting in running water is practiced in Belgium. Retting in
stagnant water is the method usually employed in Ireland and Russia. The
retting in stagnant water is more rapidly done, but there is danger of
over-retting on account of the organic matter retained in the water
which favors fermentation. In this case the fiber is weakened.

[Illustration: RETTING FLAX IN THE RIVER LYS, BELGIUM

From the Government Bulletin, "Flax for Seed and Fiber."]

In dew retting, the flax is spread