CH. Ill CARRIAGE-PART 21 



upper side of the axle are covered with steel plates 

 (transom plates) which slide on each other. When 

 the axle and the transom are parallel, these plates 

 touch each other throughout their whole length ; but 

 when the axle is turned round the perch-bolt, the 

 plates touch only near their centres and their bear- 

 ing is consequently much diminished. To obviate 

 this defect certain American builders add ' horns' to 

 the transom plates, which practically widen these 

 plates and permit them to bear upon each other 

 through the whole angle of turning. In 

 ordinary carriages the transom does not 

 bear directly upon the axle, but carries 

 upon its under side (Fig. 7) a circular 

 plate, which turns upon a similar plate at- 

 tached to the top of the axle. This is 



Fig 7 

 called the fifth-wheel, and it is generally a 



full circle, although sometimes, as in light wagons, 

 it is a half circle only. A fifth-wheel is not used in 

 a coach, but is sometimes used in a break. 



Inasmuch as the bearing just described, of the bed 

 on the axle, would be insufficient to give the requi- 

 site strength and stiffness, two additional pieces of 

 wood, the inside futchells, are mortised through the 

 axle and run backward, spreading to a width of 

 about sixteen inches at their hinder ends, where 

 they are connected by the sway-bar. In the rough 

 farm wagon, before described, this bar is straight, 

 but in a coach it is curved to a radius equal to its 

 distance from the perch-bolt, so that it is really a 



