A. Lange & Söhne Beobachtungsuhr A rare Glashuette half seconds beating deck chronometer of the k. u. k. Kriegsmarine with pivoted detent chronometer escapement and helical balance spring, sold for 275 marks to the Imperial Hydrographical Institute in Pola in 1906. A total of only 41 pieces were produced by Lange & Söhne Movm. No. 60005, Case No. 60005, Dimensions 62 mm, circa 1906, Weight 184 g, Origin German Case: silver, engine-turned, gold hinges. Dial: matt silvered. Movm.: 2/3 plate movement, nickel steel screw compensation balance, freesprung blued helical balance spring. This watch is recorded and illustrated in "Die Lange-Liste" by Martin Huber, Munich 2000, p. 97/98. Pocket chronometers with barrel Pocket chronometers are considered to be the precursors to deck watches. Lange & Soehne 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. Source: "A. Lange & Soehne" by Reinhard Meis, Munich 1997, page 211f. Case: very good. Dial: very good. Movm.: very good, capable of running, cleaning recommended. Case: very good. Dial: very good. Movm.: very good, capable of running, cleaning recommended.