THE ANCHOR ESCAPEMENT. After the crown-wheel escapement, the anchor escapement, invented by Dr Hooke or one of his contemporaries, came into general use, and remains so still; but it is not generally applied to those clocks which are required to go with the nicest accuracy. +----------------------------------------------------------------------+ | [Illustration: Anchor Escapement.] | +----------------------------------------------------------------------+ In the next illustration the tooth is seen escaping from the left pallet at the moment of the right pallet's infringing upon the opposite tooth, the pendulum is therefore to be seen still rising a little to the left, and will thus cause the wheel to recoil a little; upon its return the pallet and pendulum are again urged to the right, and so the impulse is continued which is necessary to maintain the motion. THE DEAD-BEAT ESCAPEMENT. invented by Graham is the one in most general use for the best clocks made by London makers of the highest repute. +----------------------------------------------------------------------+ | [Illustration: Dead-beat Escapement] | +----------------------------------------------------------------------+ FRENCH SINGLE-PIN ESCAPEMENT. This is a simple and ingenious escapement (see next page), which after being used for some time in both France and England went out of use, when, but recently, it was re-invented by a London watch-maker. The teeth are pins of steel set in the face of the wheel, and the upper half of each cylinder cut off as well as a small portion of the under or acting side. This escapement has one great advantage--that if a pin becomes worn or injured it is easily replaced, whereas in a wheel, if one tooth is damaged the wheel itself is worthless. +----------------------------------------------------------------------+ | [Illustration: French Single-Pin Escapement.] | +----------------------------------------------------------------------+ THREE-LEGG'D GRAVITY ESCAPEMENT. +----------------------------------------------------------------------+ | [Illustration: Another.] | +----------------------------------------------------------------------+ The above illustration represents a regulator escapement as it would appear in a front view; the pallets are lifted by the three central pins. The locking teeth vary in size from one to nearly two inches. The horizontal pieces projecting from the top of the pallets form the adjustment for the arc of the pendulum. The great advantages possessed by this escapement over all other gravity escapements, &c., are as follows:-- 1. It requires no oil. 2. The angle of the detent planes reduces the friction to almost nil. 3. As the impulse and the unlocking are in one direction, the escapement is unlocked without recoil of impulse arms.