GENERAL VIEW. SEPARATION AND CLEANING. 21 



round by cattle machinery. The process of separation is CHAP. 



thus performed. Each thin circular saw passes in every re- .' 



volution through a corresponding narrow grating,* so narrow 

 indeed that whilst the wool passes through with the saw, the 

 seed is cut off by the grating and left behind. The Cotton 

 is accordingly placed in a trough or hopper above the saw 

 wheels. The wheels as they turn round carry away the 

 Cotton, and as they pass through the grating they sepa- 

 rate the wool from the seed. Meantime a cylinder sur- 

 rounded with brushes revolves in an opposite direction, and 

 not only brushes away the wool from the saw wheels, but 

 cleanses it from all impurities. The attempts which have 

 been made to adapt this machine to Indian Cotton, and to 

 invent some other Cotton cleaning machine, which should 

 combine the perfection of the saw wheels and brush wheel 

 with the cheapness and simplicity of the churka, will be 

 illustrated in the following pages.f 



The Thresher. This machine was originally intended 27 

 to purify the seed Cotton from leaves and trash prior to 

 ginning ; for though the brush wheel of the saw gin suffici- 

 ently cleaned the wool, yet it was found that the gin worked 

 more easily if the principal trash was thrown off prior to the 

 submission of the seed to the action of the saws. The thresher 

 consists of a large trough or hopper in which two or three 

 cylinders revolve, being turned round by the same motive 

 power which turns the gin. The seed Cotton is thrown into 

 this trough, and thereupon is rendered so loose and lively by 

 the action of the cylinders, that the trash falls off, and 

 passes through a grating in the bottom of the trough into a 

 receptacle below. The seed Cotton thus purified is removed 



* Description of Whitney's Saw Gin. Cotton Reports (1836) p. 430. 

 Here, as elsewhere, the compiler has indicated the sources' of his inform^- 

 tion, though he has found it necessary to express himself in totally dif- 

 ferent language. 



f A description of the Cottage saw gin will be found at para 245, accom- 

 panied by an illustration. This will be found sufficient to explain the prin- 

 ciple of the American gin. 



