A very good larger lacquered brass aneroid pocket barometer altimeter no. 6644 by Callaghan & Co, London c1885

Pocket barometer altimeter having 2½” silvered and die struck stepped dial, the twin scale outer bezel operated altitude ring with “Higher” running from 0 to 8,000ft, “Lower” from 0 – 1,000ft each divided to 100ft, inner barometric scale calibrated in inches with a range from 22” – 31”, divided to 1/50”. The upper part signed by the maker, “Callaghan & Co,” the lower with address “23a New Bond St, Corner of Conduit St, London.” Blued steel pointer, bevelled glass.

The first quality movement based on the Vidie pattern driven from a single 1¾ nickel alloy capsule tensioned on a C spring, all raised over a lacquered brass chassis. The whole enclosed within a drum form case, engine turned bezel, pendant and bow, calibration port to verso.

Presented in its original pig skin over wood, green velvet and silk lined travel case, the lid silk bearing the Callaghan logogram. Snap closure on a button release. The outer lid with remains of gold embossed initials “H.S.W.” and the underside marked with hand-inked message: “Augt 1908, from G.S.W.”

Condition: The subject of a full service, conservation, and calibration under laboratory conditions, see performance chart from dynamic test.

The dial essentially unmarked, crisp with good vibrancy. The lacquered brass case retaining virtually all its original finish, the bow a replacement. The travel case structurally sound, the leather covering worn and discoloured, the sides re-covered, the fabric lining faded and the lid silk perished.

Comments: A good example in generally very original condition, the brass case and dial being exceptional.