PLOWING, SUBSOILING, AND TRENCHING. I35 



verize it as much as possible, and push it out of the way, to make 

 room for the next bite. As a merely mechanical operation the 

 plowing of pure sand, which it is impossible to turn in a regular 

 furrow, affords the best model, and any arable soil would be im- 

 proved by being made as fine as sand, so that it would not turn 

 in a regular furrow. 



The English use, very extensively, an implement called a 

 grubber, which is a stronger and deeper cultivator, loosening the 

 soil more completely than any plow for a depth of 6 or 8 inches, 

 when drawn by horses. Its teeth project forward like the point 

 of a plow, so that their action is more upward than that of the 

 harrow, while they hold better to the ground. 



THE KIND OF PLOW TO BE USED. 



A single manufacturer of agricultural implements in New York 

 city advertises over a hundred varieties and sizes of plows, and 

 there are hundreds of other large manufacturers and dealers in the 

 country who would add immensely to the number from which we 

 may select. 



In choosing a plow for light land or heavy ; for sod or stubble ; 

 for shallow work or deep ; for sand, clay, gravel, or plastic mould, 

 there are many considerations which should influence us, most of 

 which are familiar to all practical plowmen, and none of which 

 are so well defined that they can be made the basis of any estab- 

 lished rule. Lightness of draft and uniformity of work are the 

 great things sought after, and they are very important ; but some 

 lightness of draft may be very well sacrificed to completeness 

 of the pulverization of the furrow slice, and uniformity — except 

 in plowing grass land — is of much less consequence than thorough 

 breaking. 



In all the investigations that have been made concerning the 

 draft of plows, from the tim'e when President Jefferson submitted 

 to the French Institute his paper on the true shape of the mould- 

 board, and throughout a long course of mathematical philoso- 

 phizing on the subject, the only thing of universal application that 

 can be said to be established as a rule^ is, that on ground in which 



