German half seconds beating deck chronometer Circa 1924

Open faced deck watch with helical balance spring
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An important, as new Glashütte half seconds beating deck chronometer with pivoted detent chronometer escapement and helical balance spring, sold in 1924 for 540 Swiss Francs.
Silver case, tiered, polished, case design “Jürgens”, gold hinge. Silvered dial, radial Roman hours, auxiliary seconds, blued spade hands. 3/4 plate movement, frosted, gilt, Grossmann’s pivoted detent chronometer escapement with 2 screwed gold chatons, nickel steel gold screw compensation balance with 14,400 alternations per hour, freesprung blued helical hairspring, very finely engraved balance cock, gold chronometer wheel.
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Diameter: 63 mm
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Weight: 193 g
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Signed: A. Lange & Söhne, Glashütte B/Dresden
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Pocket chronometers with barrel Pocket chronometers are considered to be the precursors to deck watches. Lange & Söhne originally produced pocket chronometers with going barrels for scientific purposes. Often set in wooden boxes, they were to be used as deck chronometers on ships. Following this style the watches were designed with 14,400 alternations per hour; as a result the second hand was able to jump every half second. The watches all have pivoted detent escapements, which were designed in two different styles: one version was the chronometer escapement according to Berthoud, the other the escapement according to Julius Grossmann, which had an additional safety lever to prevent the escapement wheel from going on once the balance had been taken out.