With Uhrenmuseum Glashütte Certificate dated 25 March 1997 confirming the sale of the present pocket chronometer to the Hydrographic Office of Pola, Istria, on 31 December 1904 for the amount of DM 255.
It is listed in Die Lange Liste by Martin Huber, p. 97, chapter "1/2-Seconds-Chronometers with and without power reserve". The balance is oscillating at a rate of 14,400 half oscillations per hour, corresponding to a half jump of the second hand.
As of around 1880, A. Lange & Söhne produced small series of pocket watches with chronometer escapements. The first series were fitted with a chain fusée, the later ones, such as the present watch, with going barrels. Such pocket chronometers with going barrel and detent in the style of Louis Berthoud or Julius Grossmann were intended to be used as deck chronometers for scientific purposes.