CH. X SWINGING OF A COACH 1 67 



landau, runs hard, especially on a soft road, because 

 the hind wheels do not follow promptly, and some- 

 times run partly sideways in lines different from the 

 front wheels ; but within the limits of variation of 

 distance, possible in a coach, this can occur in only 

 such a small decree that the disadvantage is more 

 than balanced by the other advantages of a longer 

 coupling. 



A very short-coupled coach can never be entirely 

 safe at high speeds, especially if the horses are 

 galloping ; a short wheel base, overhung in front 

 by the body, will cause the coach to rock to and fro, 

 and especially to swing sideways. A short base is 

 generally obtained by putting the front wheels far 

 under the front boot, 

 and the effect of this 

 projection of the front 

 of the coach beyond the 

 perch-bolt can be ap- 

 preciated by imagining ' i-i ] ' u — J 

 the front axle pushed IG " 75 ' 

 back nearly as far as the centre of the body, and the 

 coach pulled from that point. It will be seen that a 

 slight side motion of the front wheels will be greatly 

 magnified at the front end of the coach, and will 

 cause a dangerous swing (Fig. 75). 



The distance between the axles of a coach should 

 not be less than 6 ft. 6 in. 



A third element of resistance to the motion of a 

 vehicle, is the action of gravity when ascending a 



