Cylinder escapement stopwatch, 1748.
© Science Museum / Science & Society Picture Library
This watch with cylinder escapement was made by George Graham (1673-1751) of Fleet Street, London. Since their origins in the 15th century until the end of the 17th century, the verge escapement had always been employed in watches, but, in about 1720, Graham introduced an entirely different escapement known as the cylinder. Graham was also one of the first watchmakers to use a pierced jewel as the end bearing of the balance-wheel shaft because the hardnes of the jewel minimised friction.