PLOWING, SUBSOILING, AND TRENCHING. 137 



a wheel would not be clogged up, a wheel on the front part of 

 the beam lessens the draft of all plows, and makes them work 

 more easily generally. After the world has been supplied, for 

 three-quarters of a century, with diagrams and formula on the 

 direction in which the furrow-slice moves over the mould-board, 

 — all of which prove the advantage of a hollow form, so regu- 

 lated that a straight edge may be laid across any part of it, at 

 right angles to the line of motion, touching at all points, — there 

 comes a " convex mould-board " plow, (on which a straight edge 

 so placed will touch only at a single point,) which is claimed to 

 be in all ways superior, and which, in my hands, has certainly 

 performed very satisfactorily ; and the "cylinder" plow, on which 

 it would touch at only two points. 



This is, it must he confessed, a humiliating fact, and it at 

 least shows that science has thus far failed to appreciate all of the 

 resisting forces which come into action in the process of plowing ; 

 and it conveys to the farmer the intimation that he should attend 

 even more to the completeness with which a fair expenditure 

 of the force of his team will break up his land than to the ease 

 with which he can do a certain amount of work. It is not quite 

 true that the hardest plowing does the most good ; but, as above 

 stated, some heaviness of draft is well compensated for by more 

 complete pulverization. 



In making a selection of plows, tlierefore, we can hope for but 

 little aid from books, and, more than in almost any other depart- 

 ment of our work, must depend on practical experience and 

 a judicious observation. Obviously, that plow is the best which 

 will do the work as it ought to be done with the least expenditure 

 of force. My own experience has led me to believe that, for 

 light work — not more than seven inches in depth — I get the most 

 complete pulverization that is possible with one pair of horses, from 

 the use of Holbrook's stubble plow. No. 66, Fig. 58, or of 

 Allen's cylinder plow, with skim attachment. Fig. 59 ; and for 

 heavy work, with a strong double team, going to a depth of nine 

 or ten inches, from the Ames Plow Company's Eagle, No. 25, 

 Fig. 60. 



