12 FOltM AND ACTION. 



THE BACK AND LOINS. 



" The back of a horse, to be a good one, should sink a little below the withers, 

 but the other part should never be too low, but always straight. When 

 the back is higher behind than forwards, he is apt to be pinched in his 

 shoulders, which makes him both weak and unsightly ; besides, his hind 

 parts are rendered so heavy thereby, that he generally has an awkward 

 clumsy gait, and moves but slowly. If a horse's back is too short in 

 proportion to his bulk, and yet he is in other respects well built, he may 

 hold out pretty well on a journey, but such are generally slow, and 

 never make a good appearance ; but if at the same time he is tall, and 

 has very long legs, his worth is but trifling. If his back is a little arched 

 behind the saddle, it is a sign of strength, and shews fitness both for 

 hunting and travelling." — Farrier^ Dictionary. 



The strength of arched structures is well exhibited in works of 

 art. Wherever the architect requires great strength and resist- 

 ance he adopts the form of the arch. Between the columns of spa- 

 cious buildings he extends arches, by which their walls are ren- 

 dered more secure, in being bound together, and their roofs better 

 supported ; and in the construction of bridges across waters of any 

 extent, he employs an arch, or a succession of arches. That won- 

 derful work, the Tunnel underneath the bed of the Thames, con- 

 sists of a series of united arches of substance sufficient to resist 

 the pressure of the superincumbent body of water, which at high 

 tide is estimated at an almost incredible weight. 



With all the strength and power of resistance of the archi- 

 tectural arch, the arcs of the spine possess a degree of mobility, 

 enabling them to alter their figure, to become larger or smaller, 

 elliptical or circular, according as circumstances require : a pro- 

 perty that could not be given to the mechanical arch without ren- 

 dering it unstable and detracting considerably from its strength. 

 At the same time it is worthy of remark, that, wherever there is any 

 elasticity arising either from the kind of materials of which the arch 

 is composed, or from the nature of its construction, it is invariably 

 found to possess, in consequence, increased powers of resistance. 

 A happy elucidation of this is seen in the common violin, which, 

 when strung up to concert pitch, has been calculated to be actually 

 sustaining a force equal to eighty pounds; under the pressure of 

 which it would certainly break were it not for its arched form and 



