Description: Full plate going fusee movement (46.5mm diameter) with Prest keyless mechanism, barrel bridge engraved with scale featuring specific screw holding the the steel bearing supporting one end of the main contrate of the winding wheel. Jeweled (sapphire) cylinder escapement, flat steel balance wheel, spiral balance spring. J R Arnold’s special shaped compensation curb. Enameled copper dial signed ‘Arnold’ and numbered ‘No.24’, subsidiary seconds at 6 (A).
Published: Listed in: Mercer V., John Arnold & Son, The Antiquarian Horological Society, London, 1972
Additional Info:
This is the earliest known movement featuring the Prest keyless system. Thomas Prest, foreman for the Arnold firm since 1784, took the patent out for this first commercially successful keyless system (patent 4501, 20th October 1820). Later the system was taken over by Charles Frodsham. (A)
Antiquarian Horology 
