152 SCIENCE OF SUCCESSFUL THRESHING. 



harder to knock out of the heads than bound grain, but no 

 trouble is experienced with the "Case" separator in head- 

 ings, if the cylinder and concaves be in good condition. Most 

 of the grain raised on the Pacific coast is headed, and a 

 special feeder, known as the "Spokane Feeder," is used, 

 usually in connection with derrick-forks. In the more east- 

 ern headed grain districts, the mounted feeder carrier is 

 used as an extension to the regular bundle feeder. 



Threshing Wheat. Ordinarily, it is not difficult to do 

 good work in threshing wheat with a separator which is in 

 good condition. To get the best results, the cylinder, es- 

 pecially, should be in good repair and it should maintain a 

 uniform speed. The speed should be fully up to the regula- 

 tion, 750 revolutions for the twenty-bar cylinder or 1075 

 revolutions for the twelve-bar cylinder. It is seldom that the 

 ordinary varieties of wheat cannot be threshed with four 

 rows of concave teeth. Before concluding that more are 

 required, see that the teeth are in good condition, and that 

 the cylinder fully maintains the given speed. It is generally 

 admitted that four rows of concave teeth are more effective 

 if a blank concave be placed between the filled concaves, 

 and that the straw is less cut up if the filled concaves be 

 placed together, but some good operators do not agree with 

 the former statement. However, with this in mind, it will 

 not be difficult for an operator to determine which arrange- 

 ment is best suited to the particular conditions under which 

 his machine is at work. Good operators judge by the work 



