CHAPTER VI 
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, woods, cork, elastic gums, 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- 
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