CHAP. VIIT. 



MACHINES FOR DRESSING CORN. 



779 



it without going on his knees to fill the sieve. One more protest, and 

 that is, that most winnowing machines are now called such on very 

 slight grounds, as beyond blowing out dust and chaff they do little. 

 When a heap of wheat contains impurities, such as wild onions (garlic), 

 or wild oats, it is very hard to make a good separation, because part of 



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the impurities owing to their size pass through or remain on the same 

 sieves as the wheat ; but they have a different density, and can readily 

 be separated by wind if it is applied under favourable conditions. 

 These latter, however, do not exist in many machines which are 

 practically little else than sifting machines. Taking all things into 

 consideration, and noticing that our experience is corroborated by the 



