Line of Draught of Plows. 177 



to a considerable degree the same efiect attends the swing plow 

 unless it is managed by plowmen more expert than are often 

 found in England or even in Scotland, and of whom scarce a score 

 could be found in the State of New York. On the other hand, 

 in stony land, or where the soil is obstructed by roots, it must be 

 confessed on all hands that a wheel is of the greatest advantage. 



8ixth — The assertion that the wheel plow requires more power 

 than the swing is completely disproved by the most accurate and 

 frequently repeated experiments. 



We have shown by geometrical reasoning that the wheel adds 

 to the draught of the plow when constantly pressed upon by the 

 trim of the plow; but this ought never to be allowed, and will 

 never occur in level and tolerably homogeneous soils, when the 

 draught is properly adjusted. The pressure will only occur in 

 coincidence with the occurrence of inequalities; but on the other 

 hand, these inequalities must be overcome by the pressure of the 

 plowman's hands, which, acting on a long lever, increases the 

 friction in a greater degree than the wheel, and therefore augments 

 the friction of the plow in a greater degree also. 



Mr. Hand ley, in a paper which received the prize of the Royal 

 Agricultural Society, details a series of experiments that he per- 

 formed with a view to the determination of this question. 



Tavo wheel plow^s were tried in connection with two swino- 

 plows. The average draught of the wheel plows was 288 pounds, 

 while the average draught of the swing plows was 341 pounds, 

 making an average difference of 53 pounds in favor of the wheel 

 plows. 



Mr. Handley's experiments were performed at Ipswich, in 1838. 

 The average weight of the wheel plows was 220 pounds; the 

 average weight of the swing plows was 135 pounds. It was 

 farther established at this trial that the draught of a plow is not 

 increased in an equal ratio w^ith its weight, for on loading one of 

 the wheel plows with 112 pounds, or 51 per cent additional 

 Aveight, the draught was only increased 33 pounds, or 12 per cent. 



These trials were repeated by Mr. Pusey in 1840, with the 

 following results: The average draught of four swing ploAvs, 

 Avorking a deep, strong loam, was 441 pounds, while that of the 

 four Avheel ploAvs, working in the same soil, was 434 pounds. 

 shoAving an average difference of 7 pounds in favor of the wheel 

 plows in this kind of soil. In a broAvn loamy sand the average 



12 



