The Lever ^ the Bit aiid Curh^ etc. 177 



diameter of the straight portion of the mouthpiece may 

 vary from a half to three-quarters of an inch ; and it is 

 scarcely necessary to, point out that the greater the 

 diameter the less painful will be its action on the bars 

 of the mouth. When under half an inch it pinches to 

 a certain extent, and should therefore be only employed 

 when one is quite certain that this is desirable. In fig. 

 13 we ha\'e made the width of the port exactly \\ 

 inches, that of the whole moutlipiece being only 4, 

 which would be rather under the mark. The thickness 

 of the mouthpieces Nos. i, 2, 3, 4 is three-quarters of 

 an inch, and these range from what is considered to be 

 the very lightest form. No. i up to No. 4, which repre- 

 sents a medium bit. We, however, should always 

 prefer No. 2 or No. 3 to No. i, for the arched form of 

 the latter throws nearly the whole pressure on the 

 tongue, and the very small amount that fcdls on the bars 

 of the mouth does so laterally., and not from front to 

 rear. This form of mouthpiece, too, is always unsteady, 

 and we have seen many horses whose tongues have been 

 nearly cut through bv its use with a tight curb. The 

 mouthpieces Nos. 5, 6, 7 are only half an inch thick, 

 which renders their action on the bars of the mouth 

 more telling; they represent sharp bits. It will not 

 escape observation that a greater thickness of the mouth- 

 piece adds, in fact, to the height of the port ; it is like 

 placing an arch on higher buttresses, but it renders the 

 action on the bars less painful, and enables us to meet 

 the exigencies of special cases — as, for instance, where 

 a horse has a thick, fleshy tongue and very sensitive 

 bars, and would not bear anything like sharp bitting. 



There is another adjustment that maybe occasionally 

 employed with advantage, and which naturally finds its 

 place here. The plane of the port is usually made to 

 coincide with that of the whole bit ; in other words, if 

 we look at the instrument from either side, the port 



M 



