FIBER CROPS 



371 



In the steam presses the cylinder and piston are about 30 

 inches in diameter and the boiler pressure of the steam is from 

 70 to 100 pounds per square inch or from 50,000 to 70,000 

 pounds per bale. Compresses are simply specially powerful 

 steam presses having cylinders from 

 80 to 90 inches in diameter, which 

 are operated under about 100 pounds 

 pressure, or from 500,000 to 600,000 

 pounds per bale. 1 



472. Ginning. Short staple up- 

 land cotton is ginned on a saw gin 

 as invented by Whitney and Holmes, 

 although subsequently much im- 

 proved in mechanical details. For- 

 merly each plantation ginned its 

 own cotton and pressed it into bales 

 by means of the wooden screw 

 presses, but at present most of the 

 cotton is ginned and pressed at the 

 public ginnery. 



A gin is usually rated by the num- 

 ber of its saws, 70 saws being the 



Standard size and capable of ginning Wood frame hand and horse cotton 



about a bale an hour. An ordinary pre , ss ' Do ^ d line shows 



levers of horse press 



public ginnery usually has four to six 



gins so arranged as to convey the cotton from the wagon through 

 a twelve-inch pipe by suction, to feed the cotton simultaneously 

 into all the gins, and to collect the ginned cotton as it leaves 

 the different gins into a single condenser which delivers the 

 lint in a continuous stream into the press. At the same time 

 the seed is delivered by special conveyer, air-blast or suction, 



1 For detailed discussion of modern cotton gins and presses, see D. A. 

 Tompkins: Cotton and Cotton Oil, Chapter VI. 



