Paragraph 40. Next to cotton, the most important vegetable fiber comes from the flax plant. This fiber is not a seed hair like cotton, but is a bast fiber; this is the tough thread-like substance found just beneath the bark of the flax plant.

Flax is raised in a great many different countries but it varies in the fineness, length and quality of its fibers. The flax plant is cut when ripe, and the stalks are then allowed to lie in a damp place, usually a swamp or an artificial pond, in order to soften the outside layer of the bark. This process is called "retting." There are a number of artificial means now adopted for the retting of flax. After this process is completed the flax is broken and by a proper machine the bast fibers are separated from the waste material. These fibers are properly cleaned, combed and spun into linen thread. This thread is very much stronger than thread spun from wool or cotton. The strength of linen thread is due to its very long libers, varying from a few inches up to several feet. Each fine fiber is a long filament composed of small cells.

Linen is used in a number of the finer fabrics for domestic use. It has been employed for various home uses for many centuries, in fact, it is almost impossible to study the history of the very earliest people without finding the use of linen. It probably came into use long before cotton was introduced.

Linen does not stand the action of alkali and soap as well as cotton; it is more difficult to dye than cotton, but is usually treated with about the same process. Linen fibers are very smooth and rather gray in their natural color, although they readily bleach to a beautiful white. This is why linen is so popular for table cloths, napkins and fine towels. Linen absorbs moisture very rapidly. In fact, one of the common tests for linen is to touch it with a moistened finger to see whether it will immediately absorb the moisture. This test is not always accurate, however, due to the fact that cotton may be so woven as to absorb moisture in almost the same way. A surer test is to moisten it with a drop of glycerine which will be readily absorbed by linen, but will not be so readily absorbed if the cloth contains cotton.

Linen burns freely in the air, almost entirely without disagreeable odor; it leaves but very little ash. Linen may usually be identified by the long slender point which is left when the thread is broken. Cotton thread usually breaks more abruptly, leaving a ragged end. There are a great many chemical tests that are used to detect the presence of cotton or other adulterations in linen, these however, are so technical that no effort will be made to present them here; they may be found in some of the references given in this text.

The following kinds of linen cloth are most common.