Rhea or China-Grass Ramie

RAMIE, RHEA or CHINA-GRASS, the product of species of the genus Boehmeria, a member of the family Urticaceae and nearly allied to the stinging nettle genus (Urtica), from which, however, it differs in absence of stinging hairs. Some confusion has arisen in the use of the various terms China-grass, Ramie and Rhea. Two plants are concerned. One, Boehmeria nivea, China grass, has been cultivated by the Chinese from very early times under the name Tschou-ma. The other, probably a variety of the same species (Boehmeria nivea, var. tenacissima), though some times regarded as a distinct species (B. tenacissima), is the ramie (Malay aim° of the Malay islands and the rhea of Assam.

B. nivea is a shrubby plant with the growth of the common nettle but without stinging hairs, sending up each season a num ber of straight shoots from a perennial underground rootstock.

The long-stalked leaves recall those of the nettle in their shape and serrated margin, but their backs are clothed with a downy substance and have a silvery appearance. The minute greenish flowers are closely arranged along a slender axis. This variety has been cultivated by the Chinese for many years, and the fibre, which is obtained from it by a tedious hand-process, has been used more or less as a substitute for silk.

The variety tenacissima differs in its more robust habit and larger leaves, which are pale green on the face and a very much Paler green on the back. They are not downy, however, and this affords a ready means of distinction from true China-grass. B. nivea is sometimes found wild in India, Malaya, China and Japan, and is probably a native of further India and Malaya. China-grass and ramie are widely cultivated not only in China, Formosa, Japan, India and Malaya, but also in Queensland, Mauritius, the Cameroons, the West Indies, Brazil, Mexico and the southern states of North America, and also in south Europe.

Cultivation.—The plant, which attains a height of from 3 to 8 ft., is grown from seed, cuttings or layers, or by division of the roots. From two to four crops per season may be obtained on suitable ground, each crop yielding about four tons of stems per acre. With only two crops per year, and a 4% yield of fibre, the resulting product would nearly reach one-third of a ton per acre. When proper attention is given to the choice of ground, and to planting, there is not much difficulty in raising a good crop; the trouble arises in the extraction of the fibre.

The stems when ripe are cut down, and after the leaves and small branches have been removed, the outer cover and the layers of fibre are stripped off in the form of ribbons. These ribbons contain the bark, the fibre and a quantity of very adhesive gum. The Chinese remove this bark and as much of the gum as pos sible before the plant has dried. This hand-process is naturally a

slow and tedious one, and many decorticators have been invented to supplant it, though none are entirely satisfactory. The fibre cannot make much headway until the operations of decorticat ing and degumming are successfully carried out on or near the growing grounds; and, until a proficient decorticator is made, the fibre should be stripped by hand and degumming begun im mediately.

Properties.—The fibre possesses some very valuable proper ties ; it is not only much stronger than any other known fibre, but almost equals some kinds of silk in its brilliance. Its lustre is about equal to that of mercerized cotton but much inferior to that of artificial silk. Ramie successfully resists atmospheric changes, is easily dyed and is affected but little by moisture. On the other hand, articles manufactured from it are said to crack and break easily when sharply bent, and on account of their hairy character have not the same smart appearance as those made from flax. Al though the fibre is in some cases 12 in. long, it varies considerably in length. This is one of the drawbacks in the industrial operations of preparing and spinning. It is impossible to make perfect yarns from fibres of various lengths; hence it is necessary either to separate the fibres into reasonable groups, or to cut them into satisfactory lengths.

Manufacture.

In general, we may say that, after decorti cation, the first process is that of degumming. This is usually done by immersing the fibre in a caustic soda solution, which is then heated in a closed vessel. The fibre is laid on galvan ized trays, of which as many as 44 can be fitted in a cage ; the cage with its charge is then placed inside the boiling keir, the lid of which is screwed down and the necessary pressure of steam ad mitted. After having been boiled a sufficient time to remove the gum, the material is lifted out, the alkali neutralized, and the fibre thoroughly washed to remove all traces of chemicals. The bulk of the water is removed by a hydro-extractor, and the fibre is then hung up or laid on perforated plates to dry. To facilitate the sub sequent process, the fibre is softened by passing it through a machine fitted with fluted rollers. Then follow the operations of dressing, roving, wet spinning and doubling, and finally the twisted thread is passed through a flame to remove superfluous hairs.

Ramie is at present chiefly used for gas mantles, for which it is particularly well adapted. It has also been used for paper making, ropes, lines, nets, underwear, and for canvas and several other fabrics. If only a good supply of clean fibre could be ob tained, there is not the least doubt but that manufacturers and machine-makers would quickly provide means for utilizing it on an extensive scale.