Page:EB1911 - Volume 10.djvu/325

Rh (c) Various animal hairs, such as those of the cow, camel and rabbit, are also employed; the latter is largely worked into the class of fabrics known as felts. In these the hairs are compacted together by taking advantage of the peculiarity of structure which causes the imbrications of the surface.

(d) Horse hair is employed in its natural form as an individual filament or monofil.

Vegetable Fibres.—The subjoined scheme of classification sets out the morphological structural characteristics of the vegetable fibres:—

In the list of the more important fibrous raw materials subjoined, the capital letter immediately following the name refers the individual to its position in this classification. In reference to the important question of chemical composition and the actual nature of the fibre substance, it may be premised that the vegetable fibres are composed of cellulose, an important representative of the group of carbohydrates, of which the cotton fibre substance is the chemical prototype, mixed and combined with various derivatives belonging to the subgroups. (a) Carbohydrates. (b) Unsaturated compounds of benzenoid and furfuroid constitutions. (c) “Fat and wax” derivatives, i.e. groups belonging to the fatty series, and of higher molecular dimensions—of such compound celluloses the following are the prototypes:—

 (a) Cellulose combined and mixed with “pectic” bodies (i.e. pecto-celluloses), flax, rhea.

(b) Cellulose combined with unsaturated groups or ligno-celluloses, jute and the woods.

(c) Cellulose combined and mixed with higher fatty acids, alcohols, ethers, cuto-celluloses, protective epidermal covering of leaves.

The letters a, b, c in the table below and following the capitals, which have reference to the structural basis of classification, indicate the main characteristics of the fibre substances. (See also .)

Miscellaneous.—Various species of the family Palmaceae yield fibrous products of value, of which mention must be made of the following. Raffia, epidermal strips of the leaves of Raphia ruffia (Madagascar), R. taedigera (Japan), largely employed as binder twine in horticulture, replacing the “bast” (linden) formerly employed. Coir, the fibrous envelope of the fruit of the Cocos nucifera, extensively used for matting and other coarse textiles. Carludovica palmata (Central America) yields the raw material for Panama hats, the Corypha australis (Australia) yields a similar product. The leaves of the date palm, Phoenix dactylifera, are employed locally in making baskets and mats, and the fibro-vascular bundles are isolated for working up into coarse twine and rope; similarly, the leaves of the Elaeis guineensis, the fruit of which yields the “palm oil” of commerce, yield a fibre which finds employment locally (Africa) for special purposes. Chamaerops humilis, the dwarf palm, yields the well-known “Crin d’Afrique.” Locally (Algiers) it is twisted into ropes, but its more general use, in Europe, is in upholstery as a stuffing material. The cereal straws are used in the form of plait in the making of hats and mats. Esparto grass is also used in the making of coarse mats.

The processes by which the fibres are transformed into textile fabrics are in the main determined by their structural features. The following are the distinctive types of treatment.

A. The fibre is in virtually continuous lengths. The textile yarn is produced by assembling together the unit threads, which are wound together and suitably twisted (silk; artificial silk).

B. The fibres in the form of units of variable short dimensions are treated by more or less elaborate processes of scutching, hackling, combing, with the aim of producing a mass of free parallelized units of uniform dimensions; these are then laid together and drawn into continuous bands of sliver and roving, which are finally drawn and twisted into yarns. In this group are comprised the larger number of textile products, such as