CHAPTER yi 

 INDUSTRIAL PLANTS 



65. Uses of industrial plants. By industrial plants we 

 mean those which yield raw materials or products used in 

 the industrial arts; that is to say, in such industries as spin- 

 ning, weaving, building, paper-making, tanning, dyeing, and 

 painting. Industrial plants cannot be separated entirely 

 from edible and medicinal plants any more than those econo- 

 mic groups can be distinguished sharply one from the other; 

 for, as we shall see, there are industrial plants which also 

 yield food or medicine or both. 



As with the economic plants already studied, so with these, 

 we shall find it convenient to classify them according to 

 the useful products which they yield. Out of the immense 

 number of industrial plants more or less useful to mankind, 

 we can here consider only a few of the most important which 

 yield fibers, uwods, cork, elastic gimis, resins, coloring matters, 

 tannins, oils, and fuels. 



66. Fibers in general. Next to food-plants those produc- 

 ing fibers have proved the most useful of all the vegetable 

 kingdom, and have contributed most to the advancement of 

 civilization. 



Mankind while yet in the stage of savagery needed some 

 sort of cordage easier to procure than sinews or strips of 

 hide, and more suitable for bowstrings, snares, fish-lines, 

 nets, baskets, and the like. He needed also some form of 

 clothing less cumbersome and cooler than that afforded by 

 the skins of animals. These needs were admirably met by 

 twisting, plaiting, or weaving the flexible strands which he 

 found strengthening roots, stems, and leaves, or by spinning 

 the woolly covering of seeds. We know that sheep's wool 

 and other animal fibers, including the silk of which the silk- 



