THE ANGLE OF TRACTION, ETC. 



235 



first of all a great loss of power by being compelled to 

 put the rudder hard down to one side in order to 

 counteract the action of the horse on the boat's head, 

 and this of course creates backwater ; and then again, 

 we have the horse compelled to exert his strength at a 

 considerable angle to the towing-path on which he 

 works, and instead of progressing straight forwards 

 with his hind feet in the tracks of the fore ones, he is 

 compelled to traverse more or less. By leng-thening 

 the towing-rope, both these evils may be diminished, 

 but they can never be altogether got rid of, for which 

 reason there is no kind of work so desti-uctive of horse- 

 flesh as towing boats on large rivers where the current 

 is strong. 



Let us now return to the horse drawing a wheeled 

 carriage, and take a two-wheeled one in the first in. 

 stance. If the two wheels were placed one behind the 

 other, as in a bicycle, one or more horses placed in 

 front in the line of traction might be harnessed each 

 with as short traces as possible. But the wheels being 



Fig. 20. 

 placed alongside of each other, the case is veiy different. 

 Let X X, fig. 20, I, represent the axle of a gig at right 



