Exceptionally English 10 Carat gold pocket watch Circa 1950

With patent Montgomery dial and special escapement 
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A fine and exceptionally rare English, keyless, 10 Carat gold filled pocket watch with patent Montgomery dial and special escapement, circa 1950. With the original Hamilton box and guarantee. Accompanied by a box and certificate. Clifford Magnetic Escapement, one of only two known examples to be fitted with a prototype Clifford magnetic escapement, by the firm of Horstmann Clifford Magnetics Ltd., of Bath, England.

Rhodium-plated movement, Geneva striping decoration, now fitted with a Clifford magnetic escapement with à Mumetal pierced escape wheel and spring blade detent type resonator. White enamel Montgomery dial with large Arabic numerals, outer minute divisions and individual Arabic minute numerals, subsidiary seconds, original blued steel spade hands. Case with screwed-down back and bezel with reeded and dot decoration, large bow. Dial, case and movement signed. Comes with the original Hamilton box and guarantee.
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Diameter: 51 mm
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Signed: Hamilton Railway Special  England
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This fascinating watch is one of only two known Hamilton watches that were sent by The Hamilton Watch Company to Horstmann Clifford Magnetics Ltd in Bath, England, for modification.
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The Clifford Magnetic Escapement was invented by Cecil F. Clifford, BSC, FBHI, in 1938 and was experimented upon during World War II with the aim of producing a silent time bomb for naval use. The theory being that as the escapement does not tick it would be undetected by sonar. The escapement consists of a flat pierced sinusoidal escape-wheel made of a magnetisable material called Mumetal mounted horizontally, and a flat upright detent terminating in two prongs allowing the escape wheel teeth to pass through. After the war, Clifford approached various firms with the idea of using silent escapement in clocks and watches. He eventually joined the company of Horstmann Gear Ltd, a maker of mechanical clocks and the company became Horstmann Clifford Magnetics Ltd in 1948, in order to produce clocks and watches with magnetic escapements. The company never actually went into production with magnetic escapements but instead approached various companies to take out production licenses. The Hamilton Watch Company was approached and sent two watches over to England for the escapement to be fitted, the present watch is one of these pieces. Although it was reported that the watches performed well, Hamilton did not take out a manufacturing license and in fact nor did any other company. HCM achieved great success after 1952 with electronic clocks and watches with tuning fork mechanisms and in fact, all tuning fork clocks made in the 1960s had magnetic escapements similar to the Hamilton prototype and linked to an electronically operated transistorized mechanism. With the advent of quartz technology, the escapement became obsolete by 1970.
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Montgomery Dial is designed by H.S. Montgomery and patented on April 20, 1920. This dial is distinctive in that every minute marker has an Arabic numeral written in full.