A rare and very early gilt and lacquered brass aneroid pocket barometer altimeter by Callaghan No 1328 for J.B. Dancer, Manchester c1865

Pocket barometer having 1¾” silvered and finely divided die struck dial, the outer altimetric scale calibrated in feet with a range from 0 – 6,000ft, additional 1,000ft higher and lower scales all divided to 100ft, arrow index aligned on a rotating bezel. Inner barometric scale calibrated in inches of mercury with range from 24” – 31” and divided down to 1/10”. The upper part marked “Rain,” “Fair,” and “Compensated,” the lower part signed by the retailer, “J.B. Dancer, Manchester.” Blued steel pointer, bevelled glass.

First quality Callaghan movement constructed to the conventional Vidi pattern with ‘L’ configured cock, 1” nickel alloy single capsule tensioned on a coil spring with stirrup suspension and fine adjustment. The movement stamped with serial number “1328” and dated “25/7/65.” All contained within a stepped drum form gilt and lacquered brass case, also numbered “1328,” having banded decoration and engine turned bezel, case extension and bow, calibration port to verso.

Contained within its correct brown leather over timber, green silk and velvet lined case, snap closure on a button release.

Condition: The subject of a full service, conservation, and calibration under laboratory conditions, the movement working well with easily acceptable accuracy over the standard barometric range 28” – 31” Hg. It should be noted that this instrument does manifest relatively high levels of hysteresis, and for this reason accurate calibration is problematical. It is a product, though, of the evolving metallurgy in capsule making and the likelihood that this capsule is an alloy of nickel and silver found predominantly in very early instruments.

The dial with original silvered finish, some faint radial marks from centre visible depending upon incident light, the bezel, with altimetric ring and index, moving smoothly. The brass case retaining a good proportion of its mixture of gilt and lacquered finish, some losses to side at bottom and to verso.

The leather case structurally sound with evidence of an historic repair at the hinge, the leather in good original condition with a shine, the fabric interior, though aged, still retaining much of its original colour and vibrancy. Snap and button release locking correctly, the keeper replaced.

Comments: Anything by Callaghan is rare, and probably the majority of his production was white labelled, ie made for other retail outlets. Perhaps less well known than Negretti & Zambra but generally very much the superior, Callaghan instruments have an identity of their own, standing out for aesthetic qualities as well as premium quality in making, factually the choice of royalty and the aristocracy.

This is the earliest Callaghan pocket barometer that we have come across, and made just after Negretti & Zambra invented the watch-sized instrument. Numbered and dated, it is very much a collector’s item.