Flax culture must be divided into two branches, culture for fiber and culture for seed. In the United States flax is raised almost entirely for the seed. Linen is woven to a certain extent in this country, but the raw material is imported and the manufacture is limited almost entirely to thread, twine, and coarse materials. Very recently a new branch of flax manufacture has been attempted, in which the broken straw, left after the removal of the seed, may be converted into yarn and woven.1 Up to this time all straw left after the removal of the seed has been a waste product.
The flax plant requires a temperate climate, but grows in varied soils. It cannot, however, be grown for many years in succession on the same soil, but must be rotated with other crops. The best grades of flax for fiber are produced on fertile soils, in districts where the temperature is even, moist, and not too high, as in parts of Russia, the Low Countries, and Ireland. The temperature lines of this area would include Wisconsin, North Dakota, Minnesota, Iowa, and parts of Michigan, the states in which flax is grown for seed.
1 Described more fully on p. 120.
Flaxseed must be sown in early spring in land which is rather heavy and well drained. It requires a rich soil, not because it takes more from the soil than other crops, but because, if it is to be used for fiber, it must take it quickly. The ground must be well prepared, finely broken up, the seed sown broadcast, and is best raked in by hand. When the plants are two to three inches high they must be weeded very carefully by hand. When they are nearly grown a stalk of blue flower appears, followed by the flaxseed. Before the seed is entirely ripe, and when the stalk of the plant has turned yellow about two-thirds of the way down, the flax is harvested. In most countries the harvesting time is July. The plant should be about three feet high when pulled, and must be pulled in clear, dry weather. If flax were cut as other grains are, part of the available fiber would be lost.
The process of separating flax fibers from the rest of the plant is a long and tedious one. The seeds and leaves are removed from the stems by a process known as rippling, the ends of the stalks being put between rollers which crush off the seeds and leaves. Next, the stems are tied in bundles and put through a process of fermentation, which loosens the bast fibers from the woody portion by decomposing the resins which unite them. This process, known as retting, may be accomplished in a number of ways. Dew retting consists in spreading the fibers on the grass and leaving them exposed to the action of dews and sun for about two weeks. This method is practiced in parts of Russia and yields a silky fiber, but it is a question if the result would not be just as good if the same flax were retted in another way. A more common method is to put the bundles of flax into pools of stagnant water and allow them to remain for several days. Since gas is evolved in the process of fermentation, the bundles must be weighted down to keep them under water. Soft water gives better results than hard. A third method is that of soaking the flax in streams of running water. The famous Courtrai flax of Belgium is retted in this manner in the slow-running waters of the River Lys. Its creamy color is due probably to the soft, slow-running water, which has a peculiar ferment.
Fig. 30. Flax.
A. Michigan Flax, seeds removed B. Flax retted C. Flax scutched.
D. Flax hackled E. Flax drawn.
The dark color of B and D is due to chemical retting.
As a rule, running water gives a whiter flax than pool retting, because the water does not become so polluted. Dew retting does not produce such uniform results. Many attempts have been made to shorten the process of retting, the most successful being those in which tanks are used and the water is heated. This water may be changing or not. In this way flax has been retted in fifty or sixty hours. Retting, by whatever method, must be stopped at the right time or the fiber will be weakened and discolored. Certain chemicals added to the water hasten the process, but while they aid the destruction of the resins binding the fibers, they weaken the fiber and injure the color, thus detracting greatly from the value of the product.
Upon removal from the retting, the bundles of flax straw are set up in fields to dry, after which they are ready for the mechanical part of the separating process. The woody portion is now thoroughly rotten and may be crushed in the flax brake. The old brake consisted, of a row of heavy slats, held firmly at each end. The straw was laid across these, and another set of slats, hinged to the first at one end and weighted at the other, was dropped down on the flax, breaking the woody tissues. At the present time the same result is obtained by the use of fluted rollers run by machinery.
Scutching is the first rough process to remove the broken woody portion of the stalk. Originally a wooden block and a wooden knife were the crude implements used for this process. The flax was placed over the block and the knife struck off the woody part. A modification of this is the modern scutching machine, in which several wooden knives are mounted in a wheel and strike, as the wheel revolves, against a wooden block across which the flax is laid.
Hackling is a combing process and further frees the fiber from the woody particles. When done by hand the hackler holds a bundle of fibers in his hand and throws the free end over a set of upright teeth, drawing it carefully through. The short fibers, or tow, are separated out by this process, the long fibers, or line, remaining in the hackler's hand. Several sets of combs must be used, as the process must not only remove the tow, but must separate the flax into finer filaments and leave the line in untangled hanks. The tow remains in the comb and must be removed from time to time. It is used for coarse grades of yarn. The machine process differs only in the fact that metal needles, set in blocks of wood on a revolving apron, and wheels with teeth do the work of the hackler and his comb. Hand hackling usually supplements the machine work, especially for the better grades of flax.