ACTION OF LONG HEELS AND CALKINS. 213 



shown at B by describing a modification of the arc D E. From 

 the position B it passes backwards to assume the position C, 

 describing the curve E' G'. It is, therefore, clear that if the 

 heels of the shoe are longer than the hoof the prolongation will 

 describe a curve which will cut the ground surface. In other 

 words, at the moment the hoof is brought to the ground the 

 heels of the shoe will make contact much earUer than the toe, 

 and the foot will come to rest at E' instead of at G. It will 

 at once be seen how injurious this is, especially to the heels. 



Calkins are just as harmful as long heels for front feet. 

 To those who doubt this, we may commend the practical test 

 of applying a pair of front shoes with heels, say, 1 or 1^ inches 

 longer than the feet, or with calkins 1^ or 2 inches high. On 

 making the horse trot, a peculiar shoulder action will be 

 observable and the horse w^ill go as though affected with 

 Liminitis. The foot seems to be brought to the ground as 

 shown in B, fig. 205. 



In hind-feet lengthening the heels is not accompanied by 

 these disadvantages, but, w'ithin limits, tends to increased 

 speed. 



In America a practice prevails of lengthening the heels of 



trotting horses' hind shoes with this object, although the 

 rationale of the process is not recognised. The following is 

 a possible explanation. 



Before actually coming to the ground the horse's foot 

 assumes the position C (fig. 206), with the sole directed more 

 or less forwards. During the next instant it describes the arc 

 of the circle C D and is firmly pdanted on the earth. 



If, however, the heels of the shoe are prolonged, although the 

 hoof still tends to describe the curve C D (fig. 207), the heel C, 

 describing a parallel but larger curve, will touch the earth at 

 A'. The increase of the stride will then equal the distance 



