224 INDUSTRIAL PLANTS 



transported, require light fibrous material so soft and elastic that 

 it will fully occupy the sj^aces into which it may be crowded. Paper 

 consists of fibers, especiall}' rich in cellulose, which have been soft- 

 ened and compacted, and finally pressed into sheets or molded into 

 other forms as papier-mache'. Besides the more familiar uses of 

 paper for writing, drawing, printing, book-binding, boxes, and so 

 on, there are many others of considerable importance. Thus we 

 have paper garments, paper napkins and other substitutes for fab- 

 rics used in the household, paper pails and similar articles rejilacing 

 wooden ware, paper canoes and paper car-wheels. 8uch wheels hav- 

 ing steel hubs and tires, are found to wear far better than wheels made 

 wholly of steel. Fine paper is nearly pure cellulose. The larger the 

 percentage of cellulose in a fiber the better the paper it makes. 

 Fibers rich in cellulose are also the source of various cellulose prod- 

 ^icts, obtained by chemical means presently to be described. These 

 products include guncotton which is a high explosive used in the 

 manufacture of smokeless powder; collodion, of much use in surgery 

 as a covering for wounds; celluloid, the well-known substitute for 

 ivory, bone, tortoise-shell, and similar materials; and artificial silk 

 which is coming to be used widely in place of the product of the silk- 

 worm. 



From what has been said of the great variety of uses to 

 which fibers are put, it follows that the term fiber must have 

 a rather broad definition. Fibers may be either fine or coarse, 

 flexible or stiff, elastic or soft. They differ also in structure 

 and chemical composition, and in the part from w^hich they 

 are derived. They agree, however, in being comparatively 

 slender structures, Avhich although separately weak, form 

 strong yet pliable articles of manufacture when twisted, 

 woven, or otherwise intimately joined together. If w^e define 

 fiber-plants as those which j-ield slender parts of economic 

 use when thus united, it may be said that over a thousand 

 species of them are known to be used more or less in various 

 parts of the world. The great majority of these, however, 

 are used only in restricted regions and are not cultivated. 

 Less than fifty are of much commercial importance. Of 

 these the most useful are the species 3'ielding cotton, flax, 

 jute, hemp, and manila. 



Fibers may be classified most conveniently for our present 

 purpose into the following groups: (1) surface fibers, more or 

 less hair-like outgrowths; (2) bast fibers, consisting entirely 

 of such tough strands as form the bast or strength-giving 



