* 

 76 HOW TO MAKE THE FARM PAY. 



we know that they had plows with colters and without, witti 

 wheels and without them, with mould boards and without them, 

 with broad painted shares and with narrow ones, plows 

 adapted to light soils, and others adapted to clays. 



The Koman's idea of a plow Avas that of a movable wedg^, 

 but he did not comprehend the necessity of combining the 

 principles of the wedge and the screw which modern science 

 has applied to the mould-board, and on which most of its im- 

 provements have been based. 



It is apparent that by far the greater part of the draught of 

 the plow, or the strength of team required, is due to friction 

 in the soil. The cutting, raising, and turning over of the turf, 

 are comparatively easy if the mould-board is properly con- 

 structed. The friction itself is somewhat increased, to be sure, 

 by the weight of the plow, and this in turn is somewhat in- 

 creased by the weight of the furrow slice as it is lifted from its 

 bed, but the draught is not increased by an increase of speed, 

 since this does not add to the friction, which remains nearly the 

 same on the bottom of the furrow, on the land -side and 

 between the furrow slice and the mouldtboard, whether the 

 motion be fast or slow. Now modern improvement has aimed 

 to overcome the friction and resistance by an improved con- 

 struction of the mould-board, and by the use of better mate- 

 rials, for it is now well settled, by practical experiment, that 

 the draught depends l^ss on the weight of the plow itselr 

 than on its constructian. The draught is not increased in pro- 

 portion to the increase of weight, and hence, though some have 

 objected that our modern plows were too heavy, as 'com- 

 pared with those in use half a century ago, it; is universally 

 admitted that they require much less strength of team to do far 

 better work. 



"Every farmer is aware that no one form of plow can be 



