THE PLOW IN GREAT BRITAIN 139 



coulter insured a sharp crest on the furrow edge left uppermost. 

 The narrow share and long curving moldboard turned over a 

 deep furrow without wrenching it apart, and the narrow cut- 

 ting edge made it possible to maintain the proper depth of 

 furrow, even in hard ground. The resulting plow was one 

 which would not, of itself, swim freely, but the long handles 

 gave the plowman the easy control essential to a straight fur- 

 row. The plow is not regarded in England as a pulverizing 

 instrument; hence there is little longitudinal twist to the 

 moldboard, and only enough vertical curvature to invert the 

 furrow slice. Small's plow did not crumble the crest of the 

 furrow slice, and this, rather than its lightness and superior 

 mechanical construction, rendered it immediately popular. The 

 same feature to-day leads British farmers to give preference 

 to plows of heavy draft but capable of turning their ideal 

 furrow. 



By this time the conception of a plow as a combination of 

 vertical and lateral wedges had been expressed in practice, if 

 not in words. While shapes had been rendered in iron, plow- 

 making was largely the joint office of the village carpenter and 

 blacksmith, each of whom often carried out his ideas without 

 reference to the other's. Plows were generally of wood, faced 

 with strips of iron, or cast-off horseshoes. The shaping of 

 plows was largely empirical. One good plowmaker after 

 another lived, flourished, and died, and his art died with him 

 for lack of a formula for transmitting his results to his suc- 

 cessor. The maker himself could seldom duplicate an ex- 

 ceptionally fine plow, and real progress was slow. There 

 gradually came a conviction, however, that some definite 

 rule some law of nature should govern the shape of the 

 plow, that in some way the cumbersome implement could be 

 simplified, lightened, its draft diminished. 



To Thomas Jefferson, third President of the United States, 

 must be given undying fame for evolving a mathematical analy- 

 sis of the moldboard, one whereby its shape could be forever 



