Silver Hunter Cased Pocket Barometer by Negretti & Zambra c.1908

A very scarce silver full hunter cased aneroid pocket barometer altimeter and thermometer compendium by Negretti & Zambra c1908. Silver pocket barometer having 1¾” stepped silvered and die struck dial, crown operated outer altitude ring calibrated in feet with a range from 0 – 20,000ft divided down to 100ft, inner barometric scale calibrated in inches of mercury with a range from 15” – 31” divided down to ⅒”, the centre upper part marked “Compensated,” the lower signed “Negretti & Zambra, London” with serial no. “27811” surmounting a semi-circular thermometer calibrated in degrees Fahrenheit with a range from 30° – 130°. Blued steel pointer under bevelled glass. Calibration port to verso. Conventional Vidie pattern movement driven from a single 1¼” nickel alloy capsule tensioned on a coil spring. All contained within a full sterling silver hunter case, hallmarks to lid inside and case back inside “Ato” for Albert Thomas Oliver and “n” for 1908, pendant, hallmarked “Ch” for Charles Hatchman and date mark for 1902, hallmarked bow. Presented in its correct brown leather over timber, green velvet and silk lined case, snap closure on a button release. The lid outside bearing initials “H.M.L.” in gold block. Condition: The subject of a full service, conservation, and calibration under laboratory conditions, see performance chart from dynamic test. The pocket barometer movement working well, very accurate across the normal meteorological range 28” – 31” Hg, remaining acceptably accurate down to 21” Hg. The dial bright and clean with good contrast, the altitude ring operating correctly from the crown, the thermometer reading approximately 1° high at 70°F. The silver case with some very shallow depressions front and back ,though barely noticeable unless viewed with reflected high light. Some minor abrasions and wear. The hallmarks well struck retaining good definition. The travel case the subject of some restoration to leather exterior and replaced lid silk, partial re-colouring to velvet. Remaining structurally sound with good external colour, fabric interior sound with good colour. Comments: These full hunter cased instruments are really very infrequently found by any maker. Following on in the tradition of pocket watches, several makers clearly considered this was an attractive though rather more expensive alternative to the standard pocket barometer case. These were effectively watch cases modified for the fitment of barometers. Examples from this most collected of makers, Negretti & Zambra, must be accepted as very unusual, both the design and execution presenting an aesthetically highly attractive instrument. Together with its correct case this is very much a collector’s item Albert Thomas Oliver was a silversmith working in Clerkenwell, London, and specialising in gold and silver watch cases, from 1903 onwards, continuing the business of Richard James Oliver. His son, Richard Oliver, continued his business under the ‘Ato’ hallmark. Charles Hatchman was a London-based silversmith and maker of watch cases, working from 1867 onwards.  The most recent work recorded by Hatchman is dated 1874, but we have three examples showing his silver maker’s mark with date letters for 1901, 1907 and 1909.