Page:The American Cyclopædia (1879) Volume VII.djvu/272

264 FLAX fibres are tlius set free. The water most suit- able for this purpose is soft river water. The flax is left more free from color by a stream of water flowing over the bundles than if these are steeped, as is often done, in a pool, the water of which is kept to be applied to the soil. This process is called water-retting or rotting. The result is sometimes obtained by exposing the flax on grass plots to the dew and rain, when the operation is called dew-retting. This requires much longer time, and also the con- trol of extensive grass fields. It is an excellent method to combine the two processes, com- mencing with the water-retting, and when the boon is partially rotted and the gummy matter loosened, to complete the operation upon the grass ; the risk of carrying the fermentation too far and injuring the fibre is thus avoided. "When the steeping process alone is employed, the flax is removed from the water as soon as the harl is found to separate by the fingers from the boon, and this breaks without bending. At this stage also several stalks knotted together sink in the water. The duration of the process is from 6 to 20 days. The riper the plant, the longer is the time required ; hence the ne- cessity of sorting the stalks into bundles of similar qualities. The bundles, being lifted out of the water by hand, are set on end to drain for 24 hours, and the stalks are then spread upon grass, and occasionally turned, to be soft- ened and ripened by exposure for several days. "When again gathered and made into sheaves, these may be kept for years in stacks, the qual- ity of the fibre continuing to improve for some seasons. Though the fermenting process is not intended to pass to the putrefying stage, a dis- agreeable odor is given out from the flax, which even contaminates the air of the district, and the waters are so affected that the fish are poi- soned. A more expeditious and agreeable pro- cess was therefore highly desirable, and such a one was devised by Mr. E. B. Schenck of New York, and successfully introduced into the flax districts of Ireland in 1847. This consisted in steeping the stalks in water heated by steam pipes to a temperature of about 90 F. The gummy matter is thus rapidly decomposed, so that in about 60 hours the operation is com- pleted without the escape of any disagreeable odors. The mucilaginous water is then drawn off, and the flax is set to dry upon frames, the waste steam of the engine being used, if neces- sary, to heat the air for hastening the drying. Other improvements have also been introduced, as that of Mr. Bower of Leeds, which consists in rolling the stalks after they have been steeped in cold or warm water, again steeping, and again rolling. The glutinous matter is thus more thoroughly removed. The addition of a pound of caustic ammonia or of common salt or Glauber salt to every 150 Ibs. of rain water is recommended; and the temperature being kept at from 90 to 120, the operation may be completed in 30 hours. The most rapid process, however, is to steep the flax for a short time, and then exhaust the air from its fibres by the action of an air pump. Twice steeping and twice exhausting the air serve to remove the glutinous matter in a few hours. Attempts have been made to substitute for the retting mechanical methods of separating the fibre from the boon, but they have not been successful, owing to the inferior quality of the filaments thus prepared. The introduction of chemical matters to hasten the fermentation has been greatly objected to from their liabili- ty to weaken the fibres. The reducing of the fibre to the condition of cotton by the process of the chevalier Claussen has excited strong opposition on this account. He had observed that the flax caught in the branches overhang- ing a stream in Brazil, which ran through his flax fields, was by repeated wetting and ex-' posure converted into a substance exactly like cotton. He then contrived a way of attaining the same result by exposing the flax to the action of a weak alkaline solution, and after- ward removing the alkali by boiling in water to which -^-5- to -zfa of sulphuric acid is added. The straw is next steeped in a strong solution of bicarbonate of soda ; and when the fibres are filled with this salt, it is transferred to a solution of sulphuric acid, weak like the former. Carbonic acid gas is generated throughout the substance, and this bursts and splits the fibre in a remarkable manner, giving it the ap- pearance of cotton. Samples of various fabrics of this material, both alone and mixed with cotton, and others with wool, and also with silk, were placed by Claussen in the London exhibition of 1851, and attracted much atten- tion. The same article, however, appears to have been made in England and Germany du- ring the last century, and a factory was estab- lished near Vienna in 1T80 for its manufacture. Berthollet, Gay-Lussac, and Giobert have ex- perimentally investigated the subject, and Ber- thollet states that as fine cotton may be ob- tained from the commonest refuse tow as from the best flax. For some reason, however, pos- sibly the expense of the process or the inferior quality of the fibre, the operation does not seem to have prospered. After the flax has been retted and dried, it is submitted to the pro- cess called breaking, by which the straws are cracked repeatedly across, the effect of which is to produce the separation of the brittle woody portion, which falls away in pieces from the filaments when afterward beaten by a broad flat blade of wood in the operation of scutching. A variety of machines are used for cracking the boon. The most simple is made with a large wooden blade, called a swingling knife, worked by a handle at one end, and fastened by a pivot at the other into a block with a cleft into which it fits ; across this block the flax is laid, a handful together, broken by the blade, and moved along, as straw or hay is chopped in a common cutter. Other brakes are worked by the foot a grooved block being brought down by each impulse upon the flax, which is