16 PRINCIPLES OF P. r. 



it, as it would, if perfectly straight, rest on 

 the tongue, and occasion an unpleasant re- 

 straint. This passage for the tongue is often 

 made so narrow and small by the bit makers, 

 that one would apprehend they scarcely had 

 aright idea of its use. It should not, how- 

 ever, be high. From the circumstance of its 

 allowing a passage for the tongue, it has been 

 called by some, the liberty ; and, for the same 

 reason, by others, the porte; hence we have 

 the porte-mouth bit, vulgarly called among 

 the bit makers and grooms the Portsmouth 

 bit; and by a supposed counter expression to 

 this term, we probably get the Weymouth 

 bit. 



The straight part of the mouth piece which 

 rests upon the bars of the jaw is termed by 

 the French le canon, and by the old English 

 writers the jeive. This part should be well 

 polished, and may be made of any proper 

 figure, as that of a cylinder, cone, oval, globe, 

 pear shape, &c. It is obvious that the effect 

 of the curb, as far as it respects the bars, will 

 be correspondent to the thickness or thinness, 



