A most important George III mahogany longcase regulator signed “Josiah Emery, Charing Cross. London,” circa 1785

anchor

The V-shaped anchor has curved impulse pallet faces with concave entrance and convex exit surfaces intended to equalize impulse.

George Daniels in The Art of Breguet describes Breguet's earliest lever watch, made in 1786, and suggests that he learned of the escapement through his friendship with John Arnold, who introduced him to the work of John Leroux and Josiah Emery. The initial forms of Breguet's lever mirror the deadbeat anchor of the present clock:
"It will be observed that the locking faces of the pallets are curves struck from the pallet axis. This ensures that while the lever is moving during the locking and unlocking the escape wheel remains stationary. This feature was regarded as essential in early levers. In fact it is better if the face of the pallet is shaped so that the wheel recoils during the unlocking. In this way the lever can be held firmly against its banking during the supplementary arc and a steadier rate results. This alteration in the angle of the locking face is called "draw" and was not generally introduced to the lever escapement until many years later. If the escapement is without draw then the lever may not always rest against the banking and as a result the balance will engage earlier and cause a variation in rate. It is for this reason that the levers are carefully poised so that change of position of the watch will not affect the banking.
It can be seen that the impulse faces of the pallets are curved to equalize the lift [i.e. impulse] from the wheel teeth. As the pallets rotate about their axis the angle of the impulse faces changes relative to the tooth. The entry pallet increases its lift angle and the exit decreases. By curving the faces Breguet maintained the relative angle constant and so ensured a constant force of impulse. This is a totally unnecessary refinement because the lift lost on the exit pallet is very small and is compensated by a proportional increase from the entry pallet. The balance is insensitive to this small inequality in value and demands only that it receives a sufficient impulse at each oscillation."