One of George Daniels's central contributions to horology is his co-axial escapement. Having observed that the dominant lever escapement begins to change its rate after a year or two - a disturbance caused by the sliding action of the impulse elements of the escapement - Daniels set about developing a mechanism that avoided this problem. The result of his efforts was the co-axial escapement, a mechanism in which he sought to combine the strengths and eliminate the deficiencies of existing watch escapements, the lever escapement foremost among them. First devised in 1977, today it remains...