46 SEATS AND SADDLES. 



attain his object, whatever that may be as also to 

 save his horse's back, and his own purse, and perhaps 

 neck. 



To begin with the under surface of the saddle the 

 portion coming in contact with the horse's back we 

 find two principal points for consideration : its shape or 

 form, and its size or extent. One general mechanical 

 principle applies to both namely, that the larger the 

 surface over which a given amount of pressure is equably 

 spread or divided, the less will be the action on any 

 given point of the other surface in contact ; and this 

 translated into plain English means, as regards shape, 

 that the under surface of the saddle should bear as 

 nearly as possible the same relation to that part of the 

 horse's back it is intended to occupy as a mould does 

 to the cast that is taken from it, always saving and 

 excepting that strip lying over the horse's backbone, 

 which must remain altogether out of contact. The 

 notion of making one portion come into closer contact 

 than another, "giving a gripe," with the intention of 

 preventing the saddle slipping, is altogether erroneous, 

 because it is the sum total of the pressure which produces 

 the cohesion between two surfaces ; its being concen- 

 trated on one point or line does not increase this amount, 

 but is very likely to make a hole in the horse's back. 

 Which part of the horse's back it should be fitted to has 

 been " dimly shadowed forth'" in Chapter I., but shall 

 be more clearly and accurately determined in the course 

 of this present one. 



As regards size or extent of surface the meaning is, 

 that the greater this is with a given weight, the less 

 will be the pressure on any given point, and consequently 

 the less risk of sore back, provided always that the 



