Anchor escapement the tooth sliding along its surface, pushing it. Then the tooth slides off the end of the pallet, beginning the cycle again. Neither the anchor escapement nor the deadbeat form, below, are self-starting. The pendulum must be given a swing to get them going. The backward motion of the escape wheel during part of the cycle, called "recoil", is one of the disadvantages of the anchor escapement. It results in a temporary reversal of the entire wheel train back to the driving weight with each tick of the clock, causing extra wear in the wheel train, excessive wear to the
Anchor escapement is still a frictional rest escapement because the sliding of the escape tooth on the dead face adds friction to the pendulum's swing, but it has less friction than the recoil escapement because there is no recoil force. In contrast to the backward slant of the anchor escape wheel teeth, the deadbeat escape wheel teeth are radial or slant forward to ensure that the tooth makes contact with the 'dead' face of the pallet, preventing recoil. In 1826 British astronomer George Airy proved that a pendulum that is driven by a drive impulse that is symmetrical about its bottom equilibrium