Verge Escapement
This form of escapement is shown in Fig. 310, which shows a plan of the escape wheel and verge in their relative positions in a watch. The inventor of this form of escapement remains in obscurity, but it appears to have been invented about the year 1000, and was the sole escapement up to the seventeenth century. The verge has served a very good purpose in its time, but its lack of correct timekeeping led to its disuse as soon as something better appeared. The escape tooth drops direct upon the impulse plane. If the momentum of the balance is sufficient to overcome the power of the mainspring a recoil is the result, but if not the result is a to and fro motion just sufficient to escape. As shown in the drawing, when the tooth in contact with the right hand pallet leaves it the tooth shown just below will fall upon the left hand pallet and impel the balance in the opposite direction. The opening of the pallets is usually ninety degrees, that is, at right angles to each other. A workman who is acquainted with the other escapements will have but little trouble in repairing the verge. Fig. 6 shows the verge clock escapement.