HARVESTING 47 



places by the larger harvesting machinery. The 

 machines used where wheat is produced in com- 

 mercial quantities are the reaper, self-binder, 

 header, and the combined harvester-thresher. 

 These have several essential things in common. 

 In each, the cutting device consists of a number 

 of triangular sections, two sides of which are 

 ground to knife edge and serrated. These are 

 then fastened to a bar in the manner of saw teeth. 

 This whole device is known as the grain sickle. 

 This sickle moves rapidly back and forth through 

 stationary guards as the machine is drawn through 

 the field, and the grain is held against the sickle 

 by a reel or set of rakes. As it is cut the grain 

 falls upon the platform with straw parallel. The 

 power for this work is derived from the turning 

 of a large wheel, known as the master wheel, on 

 which the greater paft of the weight of the machine 

 rests. The sickle can be raised or lowered while 

 in motion by a lever so placed as to be within 

 easy reach of the driver. The swath to be cut is 

 separated from the remainder of the field by 

 a grain point so that no grain is run down or 

 broken. 



The above outlined essentials are common to 

 all grain-harvesting machines. Marked differ- 

 ences are found, however, in working out the 

 details of their operation. 



The Reaper. - This term is used to define a 



