A very early, possibly one of the very first gilt brass pocket watch sized aneroid barometers by Negretti & Zambra retailed by James White, Glasgow c1863

Pocket barometer having 1⅞” silvered and engraved dial calibrated in inches of mercury with a range from 18” to 31” divided to 1/10th, the lower part signed by the retailer, “White, Opticians, Glasgow,” fine blued steel pointer, rotating bezel with engraved arrow form index to gilded reflector ring.

The finely poised Vidie pattern movement driven from a single 1⅛” nickel alloy capsule, the bridge with steel facing to lower side, blued screws, the primary lever with early perhaps prototype compensation. Decorated chassis, the verso struck “1,”  sub-chassis supporting spindle and cock. All contained within a stepped drum form case, calibration port to verso, pendant and bow.

Presented in its correct oxblood and black leather over timber, plum velvet lined case, snap closure on a button release. Inner lid with later paper inserts, one an image of a pocket barometer, and the other with handwritten message “To W.G.P. Henderson from His Sincere Friend, Frank Wilson, January 1885.”

Condition: The subject of a full service, conservation, and calibration under laboratory conditions, see performance chart from dynamic test. The movement working across a wide range with more than respectable accuracy, noted maximum error 0.2”.

The dial with very slight ageing otherwise clean, very slight marks. The brass case retaining some original gilded finish. The leather travel case the subject of some restoration, structurally sound, externally with good colour, the fabric interior with some fading, otherwise sound.

Comments: Immediately this is an interesting instrument for its very long scale, 18” – 31”. The movement is unmistably very early, the verso struck “1.” This is very significant, since this is clearly the first pattern of the newly patented pocket watch sized movements, and the instrument dates to the known dates 1863-64 when these were released. It is very likely, therefore that this was one of the first batch of perfected production pieces, the significance of which cannot be over-stated – this was a design from which all pocket watch sized barometers followed.

The arrow form index is a design point not seen on any other instruments of this period. The barb type index had not appeared prior to the production of this piece.

W.G.P. Henderson: This pocket barometer would have been an expensive gift almost certainly to someone of repute and, although research continues, two possible William Hendersons in Scotland at that time surface, both with a shipping connection – Sir William Henderson (1826-1904), former Lord Provost of Aberdeen, who was a partner in George Thompson’s Aberdeen White Star Line, and William Henderson (1826-1895), founder with his brother David of D & W Henderson Ltd, shipbuilders of Glasgow.