THE ANGLE OF TRACTION, ETC. 217 



is a matter of the very greatest importance, as 

 ~we shall now proceed to point out. 



Having, we hope, convinced the reader that the 

 horse's convenience being suited is the first thing to 

 look after, let us examine for a moment which of his 

 members he brings into action in draught, how he 

 uses them, and in what direction the effort is made. 

 Plate I., opposite to the title-page, shows us the 

 shoulder-blade, but it cannot, of course, exhibit the 

 manner in which this bone is attached to the remainder 

 of the framework of the machine, the muscles by which 

 this is effected being mostly hid beneath the bone itself ; 

 some, however, are visible in Plate II. (opposite p. 43), 

 as also some others whose function it evidently is to 

 cause, on the one hand, the lower end of the shoulder- 

 blade, which is articulated (jointed) with the arm-bone, 

 to move forward at each step taken by the horse ; 

 whilst, on the other hand, the muscles that descend 

 from the back and withers at the same time cause the 

 upper end of this bone to move backward, so that the 

 shoulder-blade in fact rotates on its centre, which is fixed, 

 whilst the upper and lower ends are movable. Every 

 judge of horses knows perfectly well the great value that 

 attaches to a long shoulder-blade, because the longer the 

 arms of the lever above and below the central fixed point 

 or fulcrum, the more powerful will be the action. 



Now it seems scarcely necessary to point out that 

 the use of "breast-harness," as it is called, which one 

 sees everywhere in the east of Europe except in Eussia, 

 or the attachment of the trace so low down on the 

 hames, when a collar is used, as to bring the pull 

 opposite, or nearly so, to the articulation of the shoulder- 

 blade with the arm-bone, is perfectly analogous to a 



