THE WHEAT INDUSTRY 



different sections of the country. Large fields 

 make big machinery profitable. Where fields 

 are small the machinery is also small. The 

 width of the cylinder is always much less than 

 that of the separator behind it. This is a neces- 

 sary arrangement, for much space must be pro- 



FIG. 43. A typical four-stack setting ready to thresh. 



vided if the straw is to be shaken thoroughly and 

 thus rid of all its grain. Cylinders vary in width 

 from 1 8 to 42 inches. The width of corresponding 

 separators is 36 to 70 inches, respectively. 



The Power Thresher. - - In the early threshers, 

 attempts were made to use water power as the 

 motive force. This did not prove successful, 

 chiefly because such machines could not be lo- 



