CH. X LENGTH OF TRACE 1 9 1 



quently disclose exaggerated cases of this mistake ; 

 a small horse with a sloping shoulder, attached to a 

 carriage with a hio-h bar or swindle-tree, and with the 

 tug low, will have his collar pulled into an absurd 

 position. 



In Fig. 83, the angle of the collar is 36 degrees 

 to the vertical, and that of the trace 12 degrees 

 to the horizontal ; in Plate XXXI. these angles 

 are 36 and 16 respectively. 



In a trotting-wagon the swingle-trees are usually 

 very high, in order to give the horses ample room 

 for the action of their hind legs ; this brings the 

 traces nearly horizontal, but the draught is so light 

 that the inaccuracy is not important. 



It is a common opinion among coaching men that 

 there is a great advantage in having- the horse close 

 to Ids work, that is, in having a very short trace. 

 But this must be taken with some allowance. There 

 is no absolute mechanical advantage in a short trace. 

 A vehicle drawn along a surface by a horizontal 

 cord and a weight, passing over a pulley, will re- 

 quire exactly the same weight to move it, be the 

 cord long or short ; variations in the effect can come 

 only from the action of the animal. 



It is, of course, important that the motion of the 

 vehicle should be as uniform as possible, and that, 

 once set going, it should continue to move at the 

 same speed, so that small obstacles can be sur- 

 mounted or crushed by the instant action of the 

 horse, before the carriage has time to stop and to 



