64 SCIENCE OF SUCCESSFUL THRESHING 



With one traction wheel in a greasy mud hole or old 

 stack bottom, and the other on solid ground, the differen- 

 tial gear may be locked, but unless you understand the con- 

 sequences of doing this, as elsewhere explained in this 

 book, it will be better to get out some other way. 



The Use of a Cable. It is a good plan to carry a wire 

 cable or heavy rope with the outfit. Then when the en- 

 gine stalls, it can be uncoupled and run onto solid ground 

 where it can pull its load out of the hole by the long hitch, 

 and then be coupled up short again. A cable or rope is 

 elastic and therefore better than a chain, which is liable 

 to snap with the shock of starting the load. Where a rope 

 is used, it should have a ring spliced in one end. The 

 other end may be tied into a shackle or clevis on the engine 

 draw-bar in a "bow-line" knot, which will not slip and is 

 easily untied after being strained. A rope used in this 

 way has the advantage of being adjustable as to length. 

 If a chain be used the engine must be moved very slowly, 

 by means of the friction clutch, until all the slack is out of 

 the chain. 



Special High Grouters. Engines for Louisiana, and 

 other swampy localities, are usually fitted with pressed- 

 steel grouters or "mud-hooks," as they are called, which 

 bolt to the traction wheels, in addition to the regular 

 grouters. These are about five inches high and conse- 

 quently must be taken off before crossing bridges. (They 

 are furnished at an additional price.) 



