PLOWS FOR MECHANICAL POWER 175 



straddles a carrying wheel; hence the damaged part may easily 

 be replaced by an extra bottom or by moving the rear one into 

 its place. In the latter case, the gang is complete, lacking 

 only one furrow. For ground of varying hardness the single- 

 hitch plow offers the nicer adjustment of load to power, though 

 a single-bottom attachment is now provided by means of 

 which the double-hitch gang is made more adjustable. Either 

 is far more adaptable than the solid gang of three or four 

 bottoms, and much more compact in sizes for large tractors. 



The long lifting levers project forward, and are controlled 

 from the platform. Springs aid the operator in lifting. One 

 plow has adjustments whereby all the levers may be focused 

 near the centre of the platform, saving steps hi handling. 

 The gang is nearly always hitched to the engine by chains, 

 either crossed or straight, considerable adjustment being pro- 

 vided. This adapts it to either a high or low drawbar, and 

 brings the plows, if necessary, to the right of the engine centre, 

 so that the tractor wheels need not travel on plowed ground. 

 The attachment of beam to frame needs to be adjustable as 

 to depth only, since the engine hitch controls the width of the 

 outside furrow and all others are uniform. A bolt and upright 

 clevises are common, also various spring hitches. One of the 

 latter releases a pair of bottoms in case of a solid obstruction. 

 Another allows the plow to be wrenched sidewise without 

 springing the beam, while in case of a solid obstruction the gauge 

 wheel is drawn forward and the plow is lifted until the strain 

 is released. For the double-bottom hitch a separate clevis is 

 provided for each beam. 



The depth of plowing is regulated by the lifting levers, 

 ratchets, and gauge_wheels. as well as by the lieight of iEe 

 hitch to the plow frameT"" Adjustable stops attached to the 

 ratchets enable the plowinan to return the plows quickly to 

 the proper depth after lifting at the headland or elsewhere. 

 On straight-beam plows the adjustment for suction is usually 

 by means of a set screw, which changes the angle between beam 



