1851 Great Exhibition: Official Catalogue: Class X.: Thomas Yates
From Graces Guide
9. YATES, THOMAS, Preston — Inventor, Patentee, and Manufacturer.
Patent clock, on the detached dead-beat principle. The wheel-work is so arranged that each vibration of the balance measures half a second, while in the ordinary detached lever each vibration measures a quarter of a second. The teeth of the escape-wheel are not so much undercut as in the ordinary lever. The pallets from the point of rest are drawn a complete circle to the escape- wheel teeth; so that when the balance returns and unlocks the escapement, there is no recoil. This escapement will carry a heavier balance with less motive power, and consequently will require a stronger balance-spring.
Gold watch, beating dead half-seconds.