224 INDUSTRIAL PLANTS 



transported, require liglit fil^rous material so soft and elastie that 

 it will full}' occupj' the spaces into which it maj' be crowded. Paper 

 consists of fibers, especially rich in cellulose, which have been soft- 

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

 other forms as papier-maclie. 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 replacing 

 wooden ware, paper canoes and paper car-wheels. Such wheels ha^'- 

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

 wholly of steel. Fine ])aper 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- 

 ?(c(.s, obtained bj' 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 iiseil widely in place of the product of the silk- 

 worm. 



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

 which fibers arc 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 ]:)art from which they 

 are derived. The}- agree, however, in being comparatively 

 slender structures, which although separately weak, form 

 strong 3'et pliable articles of manufacture when twisted, 

 woven, or otherwise intimately joined together. If we define 

 fiber-plants as those which yield slender jjarts of economic 

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

 species of them are known to lie 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 im])ortance. Of 

 these the most useful arc the s]5ecies yielding cotton, flax, 

 jute, hemp, and manila. 



Fibers may be classified most conveniently for om' present 

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

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

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



