porte against this defence.--Defence by the lip.--Defence by
the teeth.--Bar of the military and driving bit.--Martingale.--Danger
does not result from power.

[Sidenote: Place of bit in the mouth.]

To give the bit its most powerful action it should be placed so low as
only just to clear the tusks in a horse's mouth, and to be one inch
above the corner teeth in a mare's mouth. The curb-chain should be so
tight as not to admit more than one finger freely between it and the
chin; these rules are simple, and should be attended to by all riders; a
horseman should no more mount with his bit improperly placed, than a
seaman should set sail with his helm out of order.

[Sidenote: Principle of the bit.]

A twitch round the lower jaw, under the tongue, on the _bars_ or parts
of the mouth _bare_ of teeth, is perhaps the most certain, powerful, and
severe instrument to hold a horse with, and it may be tightened till it
becomes a dreadful implement of torture. Next to this is what is called
the dealer's halter, which is merely a narrow thong of leather in like
manner tied round the lower jaw, under the tongue, but incapable of
being tightened or slackened like the twitch. The bit is a most
ingenious attempt to grasp the lower jaw by the same bare parts, with
the capability of contracting or of perfectly relaxing the grasp, by the
application or withdrawal of the powers of the lever. This is the
intended action of the bit,--the philosopher's stone,--after which all
bit-projectors and bit-makers have laboured; the obstacles to be
overcome are various and perhaps insuperable, and indeed could the
powers of the lever be employed on such exquisitely sensitive parts as
the bare jaws, when within this iron vice, perhaps no hand could be
found sufficiently delicate to use them. By pressing your finger-nail
against your own gums, you may form some idea of the agony such an
implement would have the power of giving to a horse; anything
approaching to harsh, hard, handling with it would drive him desperate,
and force him to throw himself over backward; the idea of lifting his
weight by such parts grasped with iron is absurd, still more
preposterously barbarous that of arresting the headlong impetus of a
falling horse by them. Fortunately the power of the rider is here very
limited, and the horse defends himself against it by throwing his head
upward and backward, and thus the rider only breaks his horse's knees
instead of his jaws