30 SCIENCE OF THRESHING. 



The manner of separation is seen to be the moving 

 of the stalks among themselves to free the confined 

 kernels and allowing gravity to act on them, causing 

 them to fall out. The speed and motion that moves 

 the stalks among themselves with the least upward 

 motion is the best for effective separation. 



RADDLES. 



The ordinary raddle is constructed of parallel belts 

 running over pulleys, connected by slats which are 

 situated far enough apart to permit the grain to fall 

 through while carrying the straw along. If their 

 motion is quite rapid they work very well, as the 

 movement keeps the sheet of traveling straw compar- 

 atively thin, thus giving the kernels opportunity to 

 fall through. The raddles should be of sufficient 

 length to allow all of the grain to work out before 

 the straw is passed over. 



Some raddles are agitated by being driven over 

 irregularly shaped pulleys which produces a rapid 

 jarring motion. This has the effect of moving the 

 straws slightly among themselves. 



The point where the straw falls on the raddle 

 needs special attention. The straw should be deliv- 

 ered to the raddle in a thin, loose mass, for when 

 large or close bunches are allowed to drop on it, it 

 carries them along without giving them a chance to 

 separate or spread out, and thus prevents the kernels 

 from falling through. 



As the straw falls on the slats of the raddle, the 

 rapidly moving bars give the straw sudden jar or 



