174 POWER AND THE PLOW 



beam and rolling coulter are essential. Otherwise the loose 

 trash and sod will gather ahead of the shin and throw the 

 plow out of the ground. 



The beam may be arched and connected directly to the frog, 

 or straight, in which case a heavy casting usually serves as a 

 standard. The casting is shaped so as to form, with the straight 

 beam, a curved throat that will clean easily. If broken it may 

 be replaced by any one, and the straight beam, if bent, may 

 have its alignment restored by any blacksmith. A sprung 

 beam will destroy the adjustment of the plow, and without the 

 factory equipment it is practically impossible to restore a 

 curved beam to its original shape. These conditions have 

 led to the adoption of the straight beam on most plows of this 

 type. One plow has provision for replacing one of the bolts 

 connecting the beam and standard with a wooden pin. Where 

 solid obstructions are met, the breaking of the pin prevents 

 damage to the plow bottom. In straight-beam plows a double 

 beam is customary, the two bars being spread apart in front 

 to give as wide a hitch as possible and thus brace the beam 

 against side strains. 



The bottoms are now commonly hitched independently or 

 arranged in independent pairs, thus being free to follow the 

 irregularities of the ground. When the plows are hitched 

 singly they follow the ground more closely than those in pairs. 

 They require quicker work at the levers at the end of the field, 

 but with the same care will leave the headland more even. 

 One type has bottoms hitched independently and raised in pairs. 

 The single-hitch plows have each a trifle more weight than the 

 double hitch to keep them in the ground, but have a narrower 

 space between clevises at the point of hitch hence are more 

 apt to dodge or "wing" i.e., tilt to one side. The plows 

 tend to balance each other in the double-hitch type. The single- 

 bottom plow is less seriously affected by an accident to one 

 unit. All units, single or double, of the same make, are inter- 

 changeable, save perhaps where one or more of the beams 



