38 SEATS AND SADDLES. 



gravity of the whole coincides with the centre of motion 

 of the vessel. This is what is called " trim," as we all 

 know ; and the yachtsman knows well the effect of 

 sending a man or two into the bows, when running 

 before the wind, and the use of keeping his hands aft 

 when in stays ; but he will be chary of altering the 

 builder's trim, which makes these two centres coincide 

 mathematically ; he may never find it again, as has 

 happened in some remarkable instances. Now the 

 horse under a rider must have the trim that suits the 

 objects of the latter ; and for general purposes the ship 

 builder's trim or the carter's trim will be found the most 

 advantageous. The bringing the rider's body, from the 

 hips upwards, slightly forwards or backwards, will 

 answer exactly the same purpose as the shifting the 

 hands in a yacht or the sacks in a cart. It can answer 

 no good purpose to alter the regular trim. To persist 

 in sailing a boat out of trim ends in a capsize, or in 

 carrying away spars at least ; just as riding out of trim 

 usually terminates in a " purl," and always in the 

 premature destruction of the horse's legs. 



And just as too heavy a bowsprit or jib-boom will 

 destroy the trim of a boat, the overhanging position of 

 the horse's head and neck destroys the animal's proper 

 trim after a rider is placed on its back ; and the question 

 is, therefore, how this may be remedied, seeing that 

 we cannot shift a head and neck like a jib-boom. 

 Fig. 3 shows three levers d N, d 0, d P, of equal 

 length, all moving round the same common centre or 

 prop dj which corresponds to the junction of the ver- 

 tebrse of the neck with those of the back in the horse. 

 Now the longer the lever the greater its power that 

 is to say, a given weight will act more powerfully at . 



