68 THE WHEAT INDUSTRY 



specially prepared for the purpose, and cattle or 

 mules are driven over it. The hoofs of the ani- 

 mals crush out the grain by repeatedly stepping 

 on the heads. In some cases a crude sled is 

 dragged over the wheat in order to assist in the 

 shattering process. By means of the hands or a 

 fork, the mixed straw, chaff, and grain are then 

 thrown into the air when a breeze is blowing. 

 The separation is accomplished by the settling 

 of the heavy grain first and by the blowing a little 

 farther on of the lighter parts. This method is 

 called winnowing and is used extensively in Asia 

 Minor, in parts of Palestine and Egypt, and to some 

 extent in many other countries. Although this 

 method is faster and less laborious than the flail, 

 it is too slow and takes too much hand labor to 

 compete with modern methods. For this reason 

 it is not adapted to the needs of extensive wheat- 

 growing regions. 



The Thresher. - The principle of the modern 

 threshing machine is the same as that of the early 

 types just described. Its function is to shatter 

 the spike and separate the wheat grain from 

 the straw and chaff. Machines of this type 

 were not introduced until 1800 and did not 

 come into general use in our country until about 

 1840. 



The modern thresher has added several attach- 

 ments so that now the complete machine consists 



