14 HOW TO RIDE. 



their own and his weight from right to left becoming more fatiguing than 

 the constant use of each pair of legs for the same functions ; and the proof 

 is, that many of these horses will go a steady trot in harness when they 

 have only their own weight to adjust. It also explains why horses, when 

 hurried in their trot, and over-weighted in the forehand, whereby the bearers 

 (fore legs) become unable to support the weight thrown more and more 

 rapidly on them by the hind legs, which now act solely as propellers, natu- 

 rally, and to save themselves from falling, " lead " with a fore leg, imme- 

 diately followed by a hind one — that is to say, break into a canter. 



Horses that overstep, that is, bring the hind feet ahead of the track of 

 print of the fore ones, will be usually found to be such as are over-weighted 

 on the forehand, whilst those that step short are usually such as are over- 

 weighted behind. 



The advantage conferred by throwing the weight forward is, that it tends 

 to increase the speed; the disadvantages attendant on it are diminished 

 stability, and the rapid using-up of the fore legs. It has been shown that 

 the centre of motion, that is to say, the point around which all otlier parts 

 of the animal move when in action, or what comes to the same thing, the 

 point where the least motion is felt, is situated somewhere in a perpendicu- 

 lar falling through the fourteenth vertebra, Plate I. 



Again, in a ship or boat of any kind, people that have experienced sea- 

 sickness soon find out where the centre of motion lies, and nestle round it ; 

 and the master who sails her knows well that his cargo or load, whatever it 

 may be, must be so stowed away that the centre of gravity of the whole 

 coincides with the centre of motion of the vessel. This is what is called 

 "trim," as we all know. Now, the horse under a rider must have the trim 

 that suits the objects of the latter, and bringing the rider's body, from the 

 hips upwards, slightly forwards or backwards, will answer exactly the same 

 purposes as shifting the hands in a yacht. 



The fourteenth vertebra indicates, by its peculiar shape and position, a 

 different function from that of the others, all of which evidently admit of 

 movement towards it, within certain limits, whilst this one, not being 

 adapted for this purpose, may so far be considered to be intended for the 

 centr-e of motion. The construction of the horse's legs, and the relative 

 position of the various bones composing them, furnish us with very clear 

 proof of this same vertebra being the real centre of motion when the horse 



