CHAPTER XXII 



LINE OF DRAFT, WEIGHT OF HORSES AND WAGOb 

 TIRES 



IT is not enough to have good horses well nourished; 

 their powers should be directed along most efficient 

 lines. Figure 92 illustrates how one span may lift 

 and roll out of its resting place a stone so large that 

 it may require three spans of animals to draw it when 

 placed on a stone -boat. However, oxen are better 

 than horses for this purpose. If it is desired to haul a 

 heavy log for a short distance, the chain is attached at 

 the lowest point, or under the side of the log. In some 

 of the old English 

 works on plowing 

 (Fig. 93), the line 

 of draft is repre- 

 sented as starting at 

 the center of resist- 

 ance, thence running - 



. -, , v 



in a straight line 



through the device 



at the end of the 



beam, and ending 



where the traces are attached to the hames. The Ameri- 



can plowman uses short traces, which results in bend- 



ing the line of draft upwards, thus diminishing the 



(347) 



FJG 92 Energy 



directed. 



