Balance cock Small metal plate screwed to the visible side of the movement. It carries the balance wheel shaft bearing.

Diamond endstone A balance wheel shaft held in place by means of a diamond counter-bearing, or endstone, was one of the hallmarks of "1A" quality pocket watches made by Lange. In Lange tourbillon watches of the new era, diamond endstones limit the axial "play" of the carriage on both sides.

Gold chaton The gold setting of a bearing jewel - in Lange watches, chatons are often secured to the three-quarter plate with two or three screws.

This large observation watch No. 83193 crafted by "A. Lange & Söhne" was sold to the Zeppelin yard at Friedrichshafen in 1935. It was used for airship navigation and air traffic control. The Physics Institute of the Clausthal-Zellerfeld Mining Academy and the Berlin Society for Time Measurement belonged to the scientific community that purchased further exemplars of this observation watch type. - 1A quality gilt movement (calibre 57): five screwed | gold chatons, engraved | balance cock with | diamond endstone, large compensation balance with gold screws, gold pallet lever. Movement diameter: 25 lignes - Silver-plated dial with subsidiary seconds and "UP-and-DOWN" power-reserve indicator, signed: A. Lange & Söhne, Glashütte b. Dresden, 83193 - Silver case with gold hinges and gold crown