A very early, gilt brass Watkin Patent extended scale barometer altimeter by James J Hicks, London, No 23, retailed by F. Robson, Newcastle-on-Tyne

Aneroid barometer having finely engraved and silvered 4½” brass dial with tri-concentric altitude and barometric scales, reading indicator set at 7 o’clock, calibrations from 26½-31 inches of mercury and from 0–5,300ft, “Watkin Patent” in an arc above the centre with “Compensated“ and serial “No 23,” the lower dial signed by the retailer “F. Robson & Co, Newcastle-on-Tyne.” Fine blued-steel index, the case having rotating bezel with mounted telltale, set with bevelled glass and having compensation adjustment to rear.

The dial with some faint ghosting to silvering, the case retaining a good proportion of original finish with various marks, abrasions, areas of oxidation and wear to lacquer.

This is a very unusual aneroid instrument, and differs in a number of ways from the standard 3″ dial Hicks pattern. The serial number is very low, and is almost certain to be a Hicks serial number rather than a Robson one since Hicks was the only manufacturer of these Watkin Patent extended scale barometers and the serial number conforms exactly in placement and style to all other known Hicks-signed altimeters of this type. Further analysis of the rear of the dial shows a substantial depression directly behind the retailer’s name, and the marks of a fine hammer or punch are much in evidence. This would indicate a change was made to this portion of the dial – most probably it was engraved with Hicks’ signature and address which were carefully hammered out from the rear and re-engraved with that of Robson.  There would be no need to amend the serial number, and there are no signs of it having been changed. Upon very close examination there is evidence that this dial may have been re-silvered locally to the Robson name and address. The re-silvering, if so, is certainly contemporary to manufacture, being of the late 19th century style, colour and texture.

The suspension ring, with swinging link, is mounted to the case by means of a heavy machined brass block affixed from the inside by screws, a design very often found on instruments with a British Military property mark (Broad Arrow). The instrument is of substantial weight and size, evidently not for transport in a pocket. With a full scale deflection of a little over 5,000ft, it would be of little use to balloonists or mountaineers.  It would, however, suit the requirements of surveyors or, indeed, the armed services.

It is most curious, given Watkin and Hicks’ close relationship with the armed services, that, to date, a genuinely military-marked Watkin Patent extended scale barometer has not been observed. It would be completely reasonable to suggest that the first few of these instruments were delivered to the government for military trials. It is conjecture but this may well have been one such. There are other differences to the standard instrument as well: the inner bezel ring is clearly silvered, whilst those on the 3″ type are grained and lacquered brass, and the bezel is retained to the case with grub screws. At some point, the clever Hicks/Watkin-pattern telltale was removed and replaced with a very standard fine short steel spur pressed into the bezel and pointing to the arbour. It is possible, therefore, that this early production instrument was manufactured for government trials, ultimately rejected, and returned to Hicks who refurbished it and sold it on to a relatively obscure maker/retailer in Scotland.

Major (later Colonel) Henry Samuel Spiller Watkin of the Royal Artillery was granted a British patent no. 3425 for a rotary indicator and dial scale on 11 March 1886.

In all, a very unusual and possibly unique instrument in good condition, most certainly for the collector. Function is highly sensitive with very smooth transition.