Sometimes called the 'horizontal escapement', a form of which was patented by Thomas Tompion in 1695 and subsequently perfected by George Graham. It will be found in many platform escapements fitted to 19th-century, and later, carriage clocks, etc. This escapement, the earliest dead-beat escapement for watches, has a steel cylinder with resting surfaces inside and outside for the escape-wheel teeth. The lifting face of tooth B is giving impulse to the exit lip, the balance rotating anticlockwise until the tooth is released by the exit lip, allowing tooth C to drop on to the outside of the cylinder. The escapement remains under frictional lock until the balance, on its return swing, allows tooth C to move on to its impulse face against entry lip D, the balance thereby receiving impulse and tooth C eventually dropping into the frictional rest position inside the cylinder, until the balance again reverses and releases this tooth to continue the cycle. The apparent advantages of this simple dead-beat escapement are offset by the difficulty of retaining oil in its proper place, and by the large radius of the frictional rest from the centre of rotation of the balance, which causes variations, the result of friction and rapid wear.