American watch with prototype magnetic escapement Circa 1950

Gold filled watch with patent Montgomery dial by Hamilton Watch Co
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An American 10 Carat gold filled open faced keyless pocket watch with a prototype magnetic escapement by Horstmann Clifford Magnetics Ltd., circa 1950. Model: Railway Special.
Rhodium-plated movement, Geneva striping decoration, fitted with a Clifford magnetic escapement with a 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, and original blued steel spade hands. Case with screwed down back, bezel with reeded and dot decoration, large bow. Dial, case and movement signed.
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Diameter: 51 mm
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Signed: Hamilton Watch Co U.S.A.
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The movement in this watch was produced at 114 784 examples between 1897 and 1914.
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This piece is one of only two known Hamilton watches to be fitted with a prototype Clifford magnetic escapement by the firm of Horstmann Clifford Magnetics Ltd. of Bath, England. 
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The Clifford Magnetic escapement was invented by Cecil F. Clifford in 1938. It was experimented upon during World War II to produce a silent time bomb for naval use. The theory is 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. A flat upright detent terminates in two prongs allowing the escape wheel teeth to pass through. After the war, Clifford approached various firms to use 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 to produce clocks and watches with magnetic escapements. The company never actually went into production with magnetic escapements but approached various companies to take out production licenses. The Hamilton Watch Company was closed 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, nor did any other company. HCM achieved great success after 1952 with electronic clocks and watches with tuning fork mechanisms. All tuning fork clocks made in the 1960s had magnetic escapements similar to the Hamilton prototype and were linked to an electronically operated transistorised mechanism. With the advent of quartz technology, the escapement became obsolete by 1970.
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The ‘Montgomery dial’ was designed by H.S. Montgomery and patented on April 20th, 1920. This dial is distinctive in that every minute marker has an Arabic numeral written in full.