THE NECK, THE HEAD, ETC. 133 



tongue lies, or the distance between the two bars inter- 

 nally, which determines how much of the mouthpiece 

 may be allowed for the port ; the remainder must be 

 reserved for the action on the bars. 



The third dimension is what we term the height of 

 the bars, that is to say, the distance between a straight 

 edge supposed to rest on the upper surface of the bars 

 at d, fig. 11, as above, and another straight edge placed 

 exactly parallel to it, and touching the undermost 

 point of the chin-groove mathematically speaking, 

 the tangent to the curve formed by the groove. This 

 latter dimension the height of the bars is perhaps 

 the most important of all, because all the remaining 

 dimensions of the bit must be deduced from it. 



The width of the mouth is, as may be supposed, a 

 very variable quantity, depending on the breed and 

 size of the horse. Nevertheless Lieutenant -Colonel 

 von Oeynhausen,* who has had occasion to measure 

 the mouths of a very great number and variety of 

 horse's, says,f that with the great majority of horses of 

 the smaller medium size, 15.1 to 15.3 hands high, their 

 dimension amounts to 4 inches. With very small and 

 very light horses one finds occasionally 3|- inches; the 

 great majority of good-sized saddle-horses, 15.3 to 16.2 

 hands, have 4^- inches, and some very large ones go to 

 4^ inches ; while 5 inches is only to be found amongst 

 very heavy draught animals : and on reducing these to 

 English measure we have 4.148, 3.889, 4.407, 4.767, 

 and 5.185 English inches. 



* Of the Austrian army perhaps the most learned man living 

 in the matter of horse-flesh, and the author of several admirable 

 works. 



f ' Zaumungs Lehre/ p. 19. 



