150 



MECHANICS. 



adopted. Tho simplest is the " drag-roUei'^'' represented, 

 in fig. 159. It is made of a log, or portion of a hollow 

 tree, into which a common two-horse wagon tongue has 

 been fitted, by which it is dragged over the ground with- 

 out rolling, grinding to powder, in its progress, every clod 

 over which it passes. The greater the diameter of the 



log, the less will 

 be the liability of 

 its clogging by 

 gathering the 

 clods before it. 

 It may also be 

 made of a half 

 Fig. 160 represents 



IGO. 



Clod-crusher. 



One-horse Clod-crusher. 



Fi-. IGl. 



log, with the round side downward, 

 a similar imple- 

 ment for one 

 horse ; this is used 

 for working be- 

 tween the rows 

 of corn in cloddy 

 ground. 



The use of these simple implements, by reducing rough 



fields to a condi- 

 tion as mellow as 

 ashes, has,in some 

 instances, been 

 the means of 

 doubling the crop. 

 It is necessary 

 that the soil be 

 dry when they 

 are used, to pre- 

 vent its packing 



CrosskilVs Clod-crusher. together. 



CrossJcilVs Clod-crusher, first used in England, is a 

 more powerful and more costly implement (fig. 161). It 



