32 JETHRO WOOD; 



formity of surface and evenness of connextion, 

 to be an elongation of the mould -board, or, as 

 it were, an extension or continuation of the 

 same. To give the cutting edge firm coher- 

 ence and connexion, it is secured to the mould- 

 board by one or more knobs, pins or heads in 

 the inner and higher side, which are received 

 into one or more holes in the fore and lower 

 part of the mould-board. By this mechanism, 

 the edge is lapped on and kept fast and true, 

 without the employment of screws. That the 

 cutting edge may be the more securely and 

 immovably kept in its place, it has a groove, 

 or ship-lap of one inch in length, below, or at 

 its under side, near the angle between the first 

 and second sides, for the purpose of holding it, 

 and for the further accomplishment of the 

 same object, another groove or ship-lap, 

 stouter and stronger than the preceding, is 

 also cast in the iron, at or near the point of 

 the mould-board, so as to cover, encase, and 



