Anchor escapement teeth, which made the escape wheel rotate once per minute so the second hand could be attached to its shaft. In a 30 tooth escape wheel the pallets span about 7½ teeth. The impulse angle of the pallets, which determined the swing of the pendulum, was 3°-4°. The anchor was the second widely used escapement in Europe, replacing the 400-year-old verge escapement in pendulum clocks. The pendulums in verge escapement clocks had very wide swings of 80° to 100°. In 1673, seventeen years after he invented the pendulum clock, Christiaan Huygens published his mathematical analysis of pendulums, "Horologium Oscillatorium". In
Escapement main advantage of the deadbeat is that it eliminated recoil. In the deadbeat, the pallets have a second curved "locking" face on them, concentric about the pivot on which the anchor turns. During the extremities of the pendulum's swing, the escape wheel tooth rests against this locking face, providing no impulse to the pendulum, which prevents recoil. Near the bottom of the pendulum's swing the tooth slides off the locking face onto the angled "impulse" face, giving the pendulum a push, before the pallet releases the tooth. This was the first escapement to separate the locking and impulse actions of