History of the Plow. 



45 



base line, form the very low triangle a d b, whose altitude at d 

 does not exceed three-eighths of an inch, or by extending the sole 

 line h d to h, the depression h a, of the point of the share below 

 this extended line, will be one-half inch nearly. Fig. 47 repre- 



li'fff. 4-6. 



o 



'■'■■■■- 



Scale 



Z.Ft. 



sents a horizontal sole shoe. Here a c is the share, 6 <i is the 

 sole flange of the body frame, the bolt hole at b being that by 

 which the palm of the right handle is fixed to the flange ; e and 

 f the two arms of the frame as cut across in the section g i, the 

 land side of the sole shoe coinciding with the land side plane ; 

 the continuation of this line g i to h exhibits the inclination of the 

 share to the land side, which, in this plow, may be taken at one- 

 half an inch. 



The inclination downward given to the share is intended, and 

 experience confirms the intention, to give steadiness of motion to 

 the implement by giving it a lengthened base on which to stand. 

 It is evident that if a base the converse of this were given to it, 

 convex instead of concave, so that it should rest on the point d, 

 when in motion, the smallest oljstruction occurring at the point 

 of the share would give it a tendency to swerve from the hori- 

 zontal line of progression, and to lose either depth of furroAv or 

 be thrown out, thus rendering the management of the plow very 

 difficult and uncertain. Even a perfectly straight base is found 



