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FARM MACHINERY 



148. Disk drills are the more recent development and 

 consist of two classes : those with single- and double- 

 disk furrow openers. In the single-disk type the disk is 

 formed much like those used on disk harrows. Some 

 form of heel or auxiliary shoe is provided to insert the 

 grain in the bottom of the furrow made. It is desirable 

 that the passage for the seed be so arranged that there 

 can be but little chance for it to become clogged with 

 dirt. The furrow opener that allows the seed to come 

 into direct contact with the disk is not to be advised, but 

 an inclosed boot should be provided to lead the seed into 

 the bottom of the furrow. Some ingenuity is displayed 

 by different makers in securing the desired results in 

 this respect. In some drills the grain is led through the 

 center of the disk. The single-disk may be given some 



FIG. 84 A STANDARD SINGLE-DISK DRILL WITH A PRESS-WHEEL ATTACH- 

 MENT. THE STEEL RIBBON SEED TUBES ARE ALSO SHOWN 



