278 ECONOMIC BOTANY. 



is six to fifteen feet (with forty to sixty joints), and diam- 

 eter one and a half to two inches. It was not known in 

 North Europe till the time of the Crusades. It went to 

 the West Indies in 1506 ; the juice is a watery solution of 

 sugar (seventeen to twenty per cent.), with traces of aleu- 

 rone grains, glutin-like substance, vegetable wax, etc. It is 

 pressed from the cane, and boiled to the point of crystalli- 

 zation ; the crystals which then form are the brown sugar, 

 and the amorphous residue forms the molasses of com- 

 merce. The brown sugar when refined constitutes the 

 white sugar, which may be in large masses, broken lumps, 

 granulated or pulverized. A considerable quantity of 

 sugar is now manufactured from the beet. Although the 

 quantity of sugar produced annually amounts to billions 

 of pounds, " yet five hundred years ago it was but little 

 known to our European ancestors, and even a century and 

 a half ago it was one of the luxuries." 



FIBRES. 



256. The various Fibres used in the manufacture of 

 fabrics, cordage, etc., may be (1) hairs, as cotton, silk- 

 cotton, vegetable silk ; (2) fibro -vascular bundles {o{ Mono- 

 cotyledonous plants), as New Zealand Flax, Manila Hemp, 

 Tillandsia ; and (3) parts of fibro-vascular bundles . (of 

 Dicotyledonous plants), as Hemp, Flax, Jute, etc. They 

 are mostly whitish in color, but may be yellow, green or 

 gray, snow-white or black. Some are lustrous, and others 

 are not. They are composed almost exclusively of cellulose; 

 sometimes they are partially lignified, and are then more 

 brittle. The amount of ash varies from .5 to 0.6 per cent. 

 The hairs are generally unicellular, filled with air, and 

 covered with a more or less distinct cuticula. The fibres 



