250 BOARD OF AGRICULTURE. [Pub. Doc. 



Experiments have shown that it requires about ninety per 

 cent of power to move the weight of the plow and to cut the 

 furrow, and only about ten per cent to turn it over. If we 

 consider that there must be a centre of resistance, it would 

 be found near the land side and not far from the sole. To 

 prevent the plow being thrown out of the land by the greater 

 pressure on the land side, early inventors placed the beam 

 at an angle to the plane of the land side. John Mears im- 

 proved upon this method by inclining the standard to the 

 right, and placing the beam directly over the centre of resist- 

 ance and in a plane parallel to the plane of the land side. 

 The inventions of James Oliver improved somewhat on 

 Mears' construction. If, when the team is attached to a plow 

 otherwise properly adjusted, it is found that a line drawn 

 from the centre of resistance to the point of draft at the 

 horses' shoulders passes through the point of attachment at 

 the beam, the greatest economy of power and ease of holding 

 will be obtained. It can be seen at once that this is true, 

 for, if the attachment were above, the plow would be in- 

 clined deeper in the ground, and if below, it would be easily 

 thrown out. 



Use or Wheels. 



The plow is not a perfect implement, because the pressure 

 of its three sides tends to make the soil more compact, when 

 it is desired to make it mellow. This is especially true of 

 the bottom of the furrow. An effort has been made to reduce 

 the friction on the sole by placing a wheel at the back part, 

 between the land side and the mold-board, but it was found 

 that the wheel soon clogged and made the running of the 

 plow unsteady, so that its use was soon abandoned. Another 

 experiment placed two wheels at the end of the beam, one in 

 the furrow and one on the land. This arrangement made the 

 plow run steadily, but the larger wheel in the furrow raised 

 the beam and forced it out too soon at the ends. It is be- 

 lieved that Zadock Harris was the first to use one wheel to 

 travel on the land, — an arrangement almost universally 

 adopted in walking plows. This wheel is merely to give a 

 uniform depth of furrow and steadiness in running. If it is 

 found that it presses hard on the land, the team is not prop- 



