Anchor escapement it he showed that the wide pendulum swings of verge clocks caused them to be inaccurate, because the period of oscillation of the pendulum was not isochronous but varied to a small degree due to circular error with changes in the amplitude of the pendulum's swing, which occurred with unavoidable changes in drive force. The realization that only small pendulum swings were nearly isochronous motivated clockmakers to design small swing escapements. The chief advantage of the anchor was that by locating the pallets farther from the pivot, the swing of the pendulum was reduced from around 100° in verge clocks
Anchor escapement it unwinds. An escapement in which changes in drive force do not affect the rate is called isochronous. The superior performance of the deadbeat over the recoil is due to improved isochronism. This is due to the different ways changes in drive force affect the swing of the pendulum in the two escapements: When the deadbeat was invented, clockmakers initially believed it had inferior isochronism to the anchor, because of the greater effect of changes in force on the pendulum's amplitude. Recent analyses point out that the nonisochronism of the anchor can cancel the circular error of the pendulum. That