History of the Plow. 



133 



mtftrtile portion, using them interchangeably, as may seem most 



convenient or applicable. 



When pretty deep trenching is to be done, the labor of opening 



the first trench is considerably greater than that required for the 



succeeding ones, whether 

 performed with spade or 

 plow, but particularly so 



J^iff. /. 



J^iff 



with the latter. Fig. 1 

 1 represents a trench about 

 nine inches deep, through 

 which the turning and 

 trench plows have each 

 passed, and the raising 

 capacity of the latter is 

 ^^^^^^^^ ^H nearly exhausted by the 

 7i bank. By strenuous effort, 

 H six inches more of depth 

 2. might be accomplished, 



but not very satisfactorily. 

 To enable the plow to 

 gain nearly the requisite 

 depth in this first trench, 

 J, I =;:^H the bank, A, must be 



removed to the position 

 represented at A, Fig. 2. 

 This may be partially 

 done with a plow, but 

 must be completed with 

 spades or shovels, when 

 the depth represented by 

 p, Fig. 3, may be easily 

 gained, but it will be 

 di65cult to go deeper in 

 the trench with any of 

 the plows here represent- 

 ed. The next proceeding 

 in order is to turn over 

 and throw down into the 

 trench, p, a slice com- 

 „. _ posed of the thickness of 



I^iff. 3. 



jp'ig. 4.. 



