Pocket Barometer Compass Compendium by Negretti & Zambra c.1880

A scarce antique lacquered brass pocket barometer altimeter compass compendium by Negretti & Zambra retailed by James Brown, Glasgow c.1880. Pocket barometer having 1¾” silvered and struck twin-scale dial, the outer altitude scale with a range from 0–8,000ft, the inner calibrated in inches with a range from 23–31" of Hg, the upper portion carrying standard meteorological wording and "J. Brown, 76 Vincent St.," the lower portion "Glasgow," and further marked "Compensated." Fine blued steel pointer set beneath a bevelled glass maintained within a rotating bezel with associated altitude scale. Conventional compensated 1¼” capsule-driven coil spring movement contained within a drum-form case, central rib, and with engine-turned end rings. The verso with centrally-mounted hand decorated compass having blued steel pointer with upper and lower bearings marked "N" and "S," swinging over a bevelled outer card with cardinals and intercardinals, compass rose motif to centre. Brass surround carrying the inscription " To Mr. Wm. Lambert from his Father's old Friend, George Thomson, 1880." Case extension with bow. Barometer compensation grub screw set to side. The whole contained within its fine bespoke burgundy Moroccan leather over wood case with green silk and velvet lining, the base with circular cut out compass viewing port. Snap closure on a button release. Condition: Fully serviced, conserved, and calibrated under laboratory conditions, the movement displaying acceptable accuracy, see performance chart. The brass case retaining most of its original lacquered finish, losses to suspension post and bow, the dial re-silvered, the glass damage-free. The leather case with minor loss around hinge and over button, otherwise in very good original condition, the linings bright. Comments: An unusual and attractive instrument in much above average condition, beautifully decorated and inscribed, and obviously a prized gift. Serviced and calibrated, the pocket barometer functions well with good progression and sensitivity. The compass finds north easily. The pocket barometer adjustment by means of what came to be known as the Whiteside-Cook system - the small grub screw is loosened, enabling the entire movement, and the pointer with it, to be rotated to the correct setting. Made by Negretti & Zambra with compass by Francis Barker, this compendium is a collaboration between two of the leading instrument makers at that time, and a measure of its quality to combine with this pattern of adjustment. Crisp original condition overall - definitely a collector’s quality piece or a wonderful gift.