THE LEVER, THE BIT AND CURB, ETC. 179 



and the two hooks will be once and a half the same 

 dimension. 



The curb-hooks form an important item in the ar- 

 rangement. It was formerly the custom to have one 

 hook attached permanently at the near side of the bit, 

 and another of a somewhat different form to the off 

 side of the curb, but it has now become usual to attach 

 a pair of hooks of exactly the same shape and dimen- 

 sions, which is a great improvement : the proper length 

 for these is three-fourths the height of the upper cheek, 

 or about 1^ inches. 



The above length of curb applies to what is really 

 employed between the two hooks, but it is usual to 

 have one reserve link at the offside, and two of these 

 at the near one, which latter are convenient, or rather 

 indispensable, for catching a proper hold of the curb 

 when being hooked on. 



We now have gone step by step through the several 

 details connected with the bit considered as a lever — 

 namely, its cheeks, and the curb with its hooks, which 

 represent the fulcinim or prop. There remains the 

 mouthpiece, which is of equal if not greater impor- 

 tance as the part of the instrument through which the 

 immediate impression is made on the mouth, and 

 therefore generally placed in the foreground by writers 

 on this subject. It appeared, however, to us to be a 

 matter of great importance to make it perfectly clear, 

 in the first place, that the entire action of the bit 

 should be concentrated on the mouthpiece, that the- 

 operation of the curb should be confined wholly to the 

 function of a painless fulcrum, and that there are cer- 

 tain nari'ow limits to the size of the upper and lower 

 bars which form the cheeks of the instrument. The- 



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