THE IMPLEMENTS OF THE FARM. 17 



Fixed threshing machines are driven by water, wind, 

 horse-power, and steam ; portable machines by steam only. 



Portable threshing machines are made of wood or iron 

 framing, trussed wood framing being preferred, and are 

 mounted on four wood or iron travelling wheels. Their 

 threshing drums are made of iron, but those with tough 

 ash beaters and steel beater plates are preferred. The 

 concaves are made wholly of iron. The drum is fed from 

 above, and should have a guard, or safety feeding board, 

 to prevent accident in feeding. From the drum the threshed 

 grain and straw is thrown on to the shaker, of whieh there 

 are two kinds, namely, the single or double crank tossing- 

 riddles, the common description, and the rotary shaker 

 (Eansomes'), which consists of a series of transverse 

 drums, each armed with three curved teeth, which revolve 

 and clean each other, and pass the straw on to the end. 

 In both cases the corn and cavings fall through to the 

 caving riddle, the straw being tossed to the straw elevator 

 beyond, by which it is stacked. Special drums are made 

 for threshing wheat, beans, rape, clover. 



In the first dressing apparatus attached to the threshing 

 machine, the cavings, chaff, sticks, stones, weed seeds, and 

 sand are separated from the corn, which is next elevated to 

 the barley awner and smutter by a blast or cup elevator. 

 From the awner and smutter the corn passes on to the 

 second dressing apparatus, which consists of a series of 

 riddles, with blast, which separate from the corn the- 

 refuse produced in the previous operation, the refuse being 

 delivered below by a spout, the corn passing on to a rotary 

 screen, which sorts it into three qualities, each being 

 spouted into its own sack. Where the chaff is used for 

 fodder it is cleaned and bagged by the machine, and where 



