214 



COTTON 



Only the ripe, twisted fibers are fit for perfect spinning and dyeing. 

 The flattened and twisted form of the cotton fiber makes it par- 

 ticularly useful for the manufacture of cloth. No other vegetable 

 fibers are like cotton in this respect. As compared with wool, the 

 cotton fiber is smooth and twisted, while a strand of wool is straight 

 and its edges are scaly. 



Fio. 82. Showing the three classes of cotton fibers: A, unripe; B, half-ripe; C, ripe (after 



Bowman). 



Desirable Qualities of the Fiber. The value of cotton fiber is 

 determined by its color, length, tensile strength, ripeness, fineness, 

 and uniformity. The lint which grades highest in these respects is 

 spun into the finer and more expensive cotton fabrics. 



Seed. About 20 per cent of the weight of the dried, mature 

 plant is in the seeds. The average number of seeds in the usual four- 

 celled boll is from thirty-five to forty ; but there is considerable vari- 

 ation, depending upon the number of cells in the boll and the vigor 



