A rare early lacquered brass WW1 wrist air altimeter AID No 320 by F.E. Becker & Co, Successors W&J George Ltd 1897, Hatton Wall, London c1916

Air altimeter having 2¼” silvered die struck stepped dial, the outer bezel operated altitude ring calibrated in feet with a range from 0 – 10,000ft and divided to 100ft increments, stations marked in red and annotated “FEET.” The inner part with barometric scale calibrated from 22–31” of mercury, divided to 10ths. The upper part marked “Compensated,” the lower with maker’s name and address, “F.E. Becker & Co, Successors, W & J. George Ltd 1897, Hatton Wall, London.” Blued steel pointer. 1.065” single nickel alloy capsule driving a conventional C spring tensioned movement, bimetallic compensation, all raised over a circular lacquered and grained brass chassis.

All contained in a heavy duty drum form case, the verso with scratched annotation  “AID 320” and dated “21/V/16,” later leather strap of correct pattern.

Condition: Fully serviced, conserved and calibrated under laboratory conditions. The dial crisp and clean, very minor marks to centre, slight signs of oxidation to silvered finish. The movement working well, some error seen at 7000ft and 8000ft – this is due to some oxidation of the drive chain. The case retaining most of its original lacquer, some slight marks, minor abrasions and losses. The later strap with some corrosion to buckle, otherwise serviceable. Bezel operated altitude ring running smoothly. Glass appears clean and chip free.

Comments: A really lovely example of this very hard to find instrument, perhaps the most refined of the standard Vidie pattern units as adapted for air altimeters. Particularly interesting as dated 1916 and marked by the Aeronautical Inspectorate Department (AID) as no. 320.

Very much a collector’s piece.