Mechanical escapement invented There is no way of knowing exactly when the mechanical escapement was invented, but it is probable that it was developed sometime during the late 1200s, around the time that the first turret clocks were constructed. The earliest reference to a true mechanical escapement comes from Richard of Wallingford’s manuscript Tractatus Horologii Astronomici, written in 1327. In it, he describes the escapement of the turret clock at the Abbey of St Albans. His description indicates that the clock contained a ‘strob’ escapement, which is a variation of the verge escapement. The strob escapement features two escape wheels on the same axle, with alternating radial teeth. The lack of a balance spring in this mechanism meant that there was no natural beat; the mechanism had a long beat of nearly 11 seconds, so the clock’s timekeeping was very inaccurate. Read more about early mechanical clocks in the Clocktime article The first timekeepers: Telling time before the pendulum clock. Image Credits Mechanical escapement of the Wallingford Clock at St Albans Cathedral. St Albans Museums, the modern replica itself is now on display in St Albans Cathedral Golden Book of St Albans, Walsingham, Thomas; Wylum, William de;(joint authorship), England [St Albans]; 1380. British Library Board 29/08/2023, Shelfmark: Cotton Nero D. VII, c12741-10
