BITS AND BITTISTG. 37 



lever ; a, i, c, represent the' ends of the upper arms 

 of the lever, showing what would be their action if 

 they were of different lengths. These are the points 

 where the curb-chain is attached to the hit. The rule 

 which has been established by experience is, that this 

 upper arm of the lever should be exactly as long as the 

 perpendicular distance from d to e. This allows the 

 chain, t, e, to lie easy and naturally in the chin-groove 

 without pinching, when the rein is held lightly, yet to 

 exercise a strong leverage when the reins are drawn. For 

 instance, when the point, /, is drawn back to the point, 

 h, it will not be able to move much farther, and a strong 

 pressure will be brought to bear on the mouth. If the 

 upper arm of the lever were twice as long as the distance 

 from d to e, reaching to a, the chain a e, if hanging in 

 the chin-groove, would have very little efEect, except to 

 pinch and torture the horse, producing the most pain 

 upon the jawbone, just above the chin-groove, causing 

 the horse to throw up his head to escape it. If, on the 

 other hand, the upper arm of the lever were made only 

 haM as long as the distance from d to e, reaching to c, 

 the chain would have very little efEect, unless it were 

 drawn so tight as to be uncomfortable even with a loose 

 rein ; so tight, indeed, that it would soon chafe the chin- 

 groove and make that so painful, that at the least touch 

 of the rein the principal efEect would be produced there 

 rather than in the mouth, and the horse would again be 

 caused to throw up his head. 



If the upper arm of the lever is of the proper length, 

 reaching to i, when the lower end of the lever is drawn 

 back to h, the upper end will be advanced to g, and the 



