370 SOUTHERN FIELD CROPS 



separated by rollers from the lint. This general type of 

 gin has been in use in India for centuries. 



The saw gin, employed to gin short-staple cotton, is a 

 modern machine, which has been second to no other agri- 

 cultural invention in its effects on the world's wealth, 

 commerce, and comfort. The sa^^' gin has made possible 

 the South's greatest industrj^, — cotton culture, — and has 

 supplied with fleecy food the textile industries of all manu- 

 facturing nations. It was invented by Whitney and 

 Holmes about 1792. Before that time a laborer -with his 

 fingers separated about one pound of lint cotton per da3^ 



A single gin of average size accomplishes the work of about 

 4000 such laliorers. Within one hundred years after its inven- 

 tion the saw gin made possible A' four-hundred-fold increase in 

 the cotton crop of the United States. 



The saw gin is also used in ginning long-staple ui)Iand cotton ; 

 but to do this without injury to the staple, the usual speed of 

 the saws should be greatly decreased. 



When long-staple upland is ginned, care should first be taken 

 to remove from the gin the roll of cotton left by the preceding 

 bale of short-staple ; for the mixing of e^'en a little of this with 

 long-staple cotton greatly lowers the selling value of the latter. 

 This is because the spinning machinerj' in any one mill is arranged 

 for a fiber of a definite length ; the admixture of fibers of widely 

 different lengths results in loss to the spinner, either by fibers 

 wasted or by the making of thread of undesiralile quality. 



344. Care of baled cotton. — Since cotton does not 

 readily absorli large amounts of ntoistiu-e, farmers and 

 warehousemen often leave bales of cotton exposed for 

 weeks or months to the weather (Fig. IGl). This results 

 in darkening and weakeiting the fillers in the otiter layers, 

 and consequently in a decreased selling value. Cotton 



