18 BULLETIN 627, U. S. DEPARTMENT OF AGRICULTURE. 



From Table VIII it "will be seen that the cost of heading and stack- 

 ing an acre of wheat varies from $1.06 to $1.38, according to the size 

 of the crew. The cost per bushel will, of course, depend upon the 

 yield. In the last two columns are shown the approximate cost per 

 bushel based on yields of 16 and 30 bushels per acre. The cost 

 per day with the small crews has been divided by 16, and the cost 

 per day with the large crews has been divided by 30. in order to ap- 

 proximate actual conditions, since the larger crews are used more 

 often where the yields are heaviest. From these columns it will be 

 seen that the cost per bushel ranges from 1| to 7 cents. The cost of 

 cutting an acre of wheat with a header and stacking the heads is very 

 little greater than the cost of cutting when the work is done with a 

 binder. It will be seen, therefore, that there is generally a saving 

 in harvesting with a header when the cost of shocking and stacking, 

 or hauling to the separator, is considered. 



COMBINES. 



By far the cheapest method of harvesting and thrashing wheat 

 practiced in this country at present is by means of the combined 

 harvester, a machine that cuts the heads from the wheat and thrashes 

 them at the same operation. Unfortunately the use of this outfit 

 has been limited to certain sections where the grain ripens on the 

 stalk. (PI. II, fig. 1.) 



" Combines/' as they are commonly called in the sections where 

 they are used, vary considerably in size and weight, according to 

 the type and make. The early forms of combines were just what the 

 name implies, i. e., a combination of two machines, a header and a 

 separator, so arranged that the header delivered the cut heads di- 

 rectly to the thrashing cylinder. The first outfits were drawn by 

 horses, and both the header and separator mechanisms were operated 

 by " bull " or drive wheels. A little later steam was utilized to oper- 

 ate some combines, and still later gasoline engines, either in the 

 form of tractors or mounted on the combines themselves as single 

 imits, were used. At present most combines are still drawn by 

 horses, although auxiliary gasoline engines frequently are used to 

 operate the mechanism, the horses merely moving the outfit. 



The combine, like most other harvesting machinery, has undergone 

 considerable improvement during the last few years, and instead of 

 being merely a combination of two machines primarily designed for 

 two different kinds of work, the combines of to-day are designed and 

 built for the complete operation of cutting and thrashing the grain. 

 The width of swath cut by combines varies from about 7 to 25 feet. 

 The first combines were used principally on very large areas of 

 wheat, and were of necessity of large size, in order to complete the 

 work during the weather suitable for harvest. The3 r required about 





