[Sidenote: Varieties of Sheep]
There are supposed to be about thirty distinct varieties of sheep, nearly half of which are natives of Asia, one-third of Africa, and only four coming from Europe, and two from America. Wool is divided into two general cla.s.ses--long and short staple, according to the average length of fiber. The long fiber wool is commonly carded, combed and spun into _worsted_ yarn. The short fiber is usually carded and spun into woolen yarn. The short fiber obtained in combing long staple wool is called "noil." It is used for woolens.
[Sidenote: Goat Wools]
Alpaca, Vicuna and Llama wools are obtained from animals which are native to the mountains of Peru and Chile. The Angora goat, originally from Asia Minor, furnishes the mohair of commerce. This fiber does not resemble the hairs of common goats in any respect. It is a very beautiful fiber of silky l.u.s.ter, which const.i.tutes its chief value.
[Ill.u.s.tration: ANGORA GOATS]
[Sidenote: Fur]
The fur of beavers and rabbits can be and is used in manufacture, either spun into yarn or made into felt. The fibers of both animals enter largely into the manufacture of felt hats.
[Sidenote: Sorting Wool]
The fleece of sheep after being sheared is divided into different parts or _sorted_, according to the quality of the wool, the best wool coming from the sides of the animal.
[Ill.u.s.tration: WOOL FIBERS
_a_--Medium Wool; _b_--Camel"s Hair; _c_--Diseased Fiber; _d_--Merino Wool; _e_--Mohair.]
[Sidenote: Scouring Wool]
As it comes from the sheep, the wool contains many substances besides the wool fiber which must be removed before dyeing or spinning. This cleansing is called _scouring_. Before scouring, the wool is usually dusted by machines to remove all loose dirt. The scouring must be done by the mildest means possible in order to preserve the natural fluffiness and brilliancy of the fiber. The chief impurity is the wool grease or "yolk" which is secreted by the skin glands to lubricate the fiber and prevent it from matting.
[Ill.u.s.tration: ONE METHOD OF WOOL SORTING
1--The Best Grade; 2--Lowest Grade; 3--Fair; 4--Medium Grade.]
[Sidenote: Scouring Agents]
In the scouring of wool, soap is the princ.i.p.al agent. Soft soap made from caustic potash is generally used as it is less harmful than ordinary hard soda soap. Pota.s.sium carbonate--"pearl ash"--is often used in connection with the soap. If the water for scouring is hard, it is softened with pearl ash. The temperature of wash water is never allowed to go above 120 F. The scoured wool weighs from a little over a half to one-third or less of the weight of the fleece.
[Sidenote: Hydroscopic Moisture]
Wool has the remarkable property of absorbing up to 30 per cent or more of its weight of water and yet not feel perceptibly damp to the touch.
This is called "hydroscopic moisture." To this property wool owes its superiority as a textile for underclothing.
[Ill.u.s.tration: WOOL SORTING]
The thoroughly 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.
[Ill.u.s.tration: 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.
[Ill.u.s.tration: 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.
[Ill.u.s.tration: 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.
[Ill.u.s.tration: RETTING FLAX IN THE RIVER LYS, BELGIUM
From the Government Bulletin, "Flax for Seed and Fiber."]
In dew retting, the flax is spread on the field and exposed to the action of the weather for several weeks without any previous steeping.
This method of retting is practiced in Germany and Russia. Warm water retting and chemical retting have met with limited success.
When the retting is complete, the flax is set up in sheaves to dry. The next operations consist of "breaking," "scutching," and "hackling" and are now done by machinery.
[Ill.u.s.tration: FIBERS OF FLAX]
Breaking removes the woody center from the retted and dried flax by being pa.s.sed through a series of fluted rollers. The particles of woody matter adhering to the fibers are detached by scutching.