FIl'.ICR CROPS 319 



if the separate fibers in a pound were placed end to end they 

 would reach 2,200 miles. 



The tensile strength or breaking strain of the cotton fiber 

 may vary from about 2.5 to 15 grams, depending on the fineness 

 and ripeness of the fiber. 1 Hilgard found American upland 

 cotton to vary from 4 to 14 grams. Silk has a greater and wool 

 a less tensile strength than cotton in proportion to the diameter 



Cotton seeds with lint attached, illustrating types of long staple cotton. 1 1mported 



Mit Ami 'Egyptian), b ordinary sea island 



(After Webber) 



of their respective fibers. The tensile strength of various 

 fibers in relation to their size and therefore their strength in 

 relation to the weight of garment may be expressed by the 

 "breaking length," which means the length of fiber which would 

 break of its own weight. 



Table Showing Length of Fiber Which Will Break of Its 

 Own Weight 



Breaking length 



Fiber in nvles 



Wool 5.1 



Jute 12.4 



Ramie or China grass . . . . . . 12.4 



Flax 14.9 



Cotton 15.5 



Hemp 18.6 



Manila hemp 19.8 



Silk 20.5 



1 In order to get concordant results, care must be taken concerning the 

 method of suspension. 



