1 



PLOUGH AND PLOUGHING, 

 ferent parts of D C at right angles to | at 45° beyond it at D. The curve 



this line, and meeting the line K E 

 {Fig. 7). These lines will be at dif- 

 Horizontal Plan of the Plough. 



A B, the Sole. C, the Fin. D C, the bottom 

 of the Turn-furrow. 



thus generated will be found to turn 

 over soils of a moderate tenacity 

 very perfectly. If it is very light, 

 the surface may be formed by arcs 

 of circles with a considerable diame- 

 ter, the concave part upward ; if it is 

 very tenacious, the convex part of 

 the arches may be upward. Thus the 

 surface may be varied without alter- 

 ing the fixed line E K. The annexed 

 figures (8, 9, and 10) will explain this. 

 The distance of the perpendicular FG 

 from the tin of the share may also be 

 varied, either lengthening or short- 

 ening the turn-furrow as experience 



ferent angles to the horizon, nearly 

 horizontal at C, where the fin of the 

 point begins, perpendicular at F, and ] may show to be most advantageous. 



Sections of the three different Turn-furrows., at different distances from the Heel. 



Fig. 9. 



A D 



" A plough has lately been con- 

 structed on this principle ; it prom- 

 ises to realize the expectations form- 

 ed of it. In soils of a loose, mellow 

 nature it answers completely, and 

 does the work more perfectly than 

 any other plough. It unites the par- 

 allelism of the sole and bottom of the 

 turn-furrow of the Flemish plough 

 with the improved shape of the turn- 

 furrow. By adopting the variations 

 in the shape of the turn-furrow which 

 we have suggested, this plough may 

 be adapted to any soil, and be used 

 with or without wheels. 



" Ploughs were formerly made of 

 wood, having those parts covered 

 with iron where the greatest friction 

 takes place, the share and coulter 

 only being of iron ; but in conse- 

 quence of the greater facUity of cast- 

 ing iron in modern times, most of the 

 parts are now made of tliis metal. 

 The beam and stilts are still usually 

 of wood, but even these are now 

 sometimes made of wrought iron and 

 cast iron. The advantages of iron 

 are its durability and the smaller fric- 

 tion it occasions when once polished 

 by use. The inconveniences are the 

 additional weight of the instrument, 

 594 



A D 



and consequent greater friction of 

 the sole. Recent experiments have 

 proved this to be greater than was 

 generally suspected. A great im- 

 provement has been introduced by 

 making the points of the shares of 

 cast iron, which, by a mode of cast- 

 ing the lower surface on a plate of 

 metal, makes one surface much hard- 

 er than the other ; and as the softer 

 surface wears more rapidly, a sharp 

 edge is always preserved. 



" The stilts of the plough are most- 

 ly of wood, ^\^lere the soil is light 

 and crumbling, without stones, a sin- 

 gle handle or stilt is sufficient ; but 

 where some force is occasionally re- 

 quired to prevent stones or other ob- 

 stacles from turning the plough out 

 of its course, two stilts are most con- 

 venient, placed at a more obtuse an- 

 gle with the sole of the plough. 



"The force required to draw a 

 plough depends, not only on the na- 

 ture of the soil, but also on the shape 

 of the plough, and especially on the 

 position of its difTerent parts with re- 

 spect to each other, so that they do 

 not counteract each other. 



" If a plough were drawn in the di- 

 rection of the sole, the obliquity of 



