162 CALIFORNIA VEGETABLES 



threshing. But beans wet on a tramping-floor while mixed with 

 pulverized leaves are irreparably damaged, being stained and heated 

 before it is possible to clean them. Every farmer who tramps out 

 his beans should be provided with sheets of canvas sufficient to cover 

 all unwinnowed ar sacked beans liable to be left out during a shower. 

 Tramping is a tedious process but it has some advantages. It is 

 the resource ever at hand to meet the exacting charges of machine 

 owners. And besides, during extreme dry weather beans can be 

 tramped well, the pods being dry and brittle while the vines are still 

 green and tough, a condition in which a machine cannot work in 

 them at all. The energetic farmer can thus often secure a large 

 portion of his crop before a machine could thresh them even if he 

 could get it. So it will probably be many years before tramping is 

 entirely abandoned. 



Machine Threshing. For many years attempts were made to 

 use modified grain threshers for separating beans. At first there 

 was too great a percentage of cracked beans, but recently machine 

 work has become more satisfactory. The following account of bean 

 threshing is prepared by L. W. Fluharty : 



The threshing is usually done with the bean huller, using either a steam 

 or gasoline engine for power. The huller is a double threshing machine. 

 There are two cylinders, one of which is placed in the rear of the other. The 

 rear cylinder operates much faster than does the front one. The cylinder teeth 

 are set one-fourth of an inch farther from the concave teeth than in the regular 

 grain separator. The front cylinder threshes only the beans from the driest 

 pods. The vines, together with the tougher pods pass to the rear cylinder, 

 thus the beans and the tougher pods are threshed by the high velocity cylinder 

 while the dry beans pass through only the one running at a low rate of speed. 

 Much cracking is prevented by this arrangement. 



A grain separator may, by proper manipulation, be made to do very satis- 

 factory work provided the beans have been stacked long enough for them to 

 go into the sweat. The vines and pods are then more nearly uniform in dry- 

 ness. All but one row of concave teeth and generally half of the cylinder 

 teeth are removed. The cylinder is run at a speed of from 350 to 400 revolu- 

 tions per minute, the speed depending upon the diameter of the cylinder the 

 larger the cylinder the slower it must be run. The drive pulley is enlarged 

 so that the separating part of the machine runs at the usual speed for separat- 

 ing grain. 



The tailings from the sieves are returned to the separator at the rear 

 instead of in front of the cylinder. By this arrangement none of the threshed 

 beans pass through the cylinder the second time. If there is a large amount 

 of green pods the tailings are sometimes taken from the machine at the bottom 

 of the elevator. In this way it is often possible to avoid mixing the green 



