History of the Plow. 



61 



Fiofs. 53 [a mul b) show shares which have been broken, and 



the Avhite lines at the edge show 



the chilled parts. 



This new process proved of 



such practical utility that it was 



soon extended to other parts. A 



Suliblk farmer invented for his 



own use a cast iron sole-shoe, 



Avhich was also chilled at the bot- J^iff- 63.— {a) 



torn. It was provided with mortises to receive the tenons of the 



wooden parts, and soon got into general use. It is represented at 



Fig. 54. The old difficulty, 

 however, still remained, not- 

 withstanding these ffreat im- 

 provements. So long as any 

 portion of the plow was 

 made by the blacksmith, 

 changes would be made in 



the curves and other parts upon which its useful action depended, 



J^iff. 64-. 



and there was a consequent uncertainty on the part of purchasers 

 whether the plows would perform good work. As improvements 



Mff. 55. 



