204 CURB-CHAIN CH. XI 



of all these bits, when the rein is buckled in one of 

 the holes in the branch, depends upon the curb-chain 

 which is attached to the upper eye of the bit and 

 passes under the chin. The tightness of the chain 

 can be regulated by engaging one or other of its 

 links in the hooks. Usually, before hooking, the 

 chain should be turned until all the links lie flat ; if 

 it is turned so that the links are open, or 'roughed,' 

 as it is called, it is more severe. There should be 

 a hook on each side of the bit, so that the chain can 

 be entirely removed for cleaning, and these hooks 

 should have spring points, or the chain will be con- 

 stantly coming unhooked. The chain should be so 

 hooked that when the bit is hanging loose, with the 

 horse's head nearly vertical, three fingers can be 

 passed between the horse's jaw and the chain, which 

 will then lie in what is sometimes called the ' chain- 

 eroove,' above the cushion-like thickening of the 

 lower lip. \\ nen the rein is pulled tight, the head 

 of the horse being vertical, the branch of the bit 

 should come to an angle of about 40 degrees with 

 the vertical ; if it approaches nearer to the horizon- 

 tal, the chain is too loose to have any effect. A 

 curb-strap, with a billet at each end to buckle in the 

 eye of the bit, is in many respects more convenient 

 than a chain, and no hooks are needed on the bit, 

 but it is not as severe as is a chain. 



Since the function of the curb-chain is to provide 

 a fulcrum on which the branch of the bit acts 

 in pressing the mouth-piece against the bars, a 



