THE PRIMER. 



elevate the head of the horse, the tension upon the 

 curb reins should for the moment be relaxed and the 

 snaffle reins be brought into play, and when these 

 have effected their object the tension upon the curb 

 reins may be resumed. 



The curb bit is desiorned to act as a lever of the 

 second class. The curb chain, passing from the 

 upper arms under the chin, gives to the upper 

 ends of the branches a fulcrum ; the power is applied 

 through the reins to the lower branches of the bit, 

 and the weight or effect is felt upon the bars of the 

 horse's lower jaw. With such loosely fitting bear- 

 ings upon the yielding head of the horse as is 

 afforded by the leather head-stall, it is impossible to 

 secure all the powers of the lever, or to give accu- 

 rately the proportions. There are cleverly con- 

 trived instruments for obtaining the measurements 

 for the curb bit, and every horse should, if possible, 

 be fitted with the bit that best suits it. Generally 

 speaking, the upper arms of the bit, from the centre 

 of the mouth-piece to the point where the curb chain 

 takes its bearing, should be from one and three- 

 quarters to one and seven-eighths inches, depending 

 upon the depth of the jaw. The branches should 

 be long or short as the rider requires a severe or a 

 mild bit. The curb chain should lie smoothly and 

 snugly in the chin groove, and this should be a 



