A unique large aneroid barometer altimeter constructed in aluminium supplied by J. Hicks for Edward Whymper, Victorian mountaineer, c1904, in original bespoke mahogany transport case

Aneroid barometer having 7” silvered, engraved and engine divided dial, the outer altitude scale calibrated from 0 – 10,000ft and divided down to 50ft, inner barometric scale calibrated in inches of mercury with a range from 21.6” – 31.4”, the upper part marked “Compensated,” the lower signed by the retailer “J. Hicks” with address “8, 9 & 10, Hatton Garden, London.” Deep mirror polished reflector ring, fine blued steel pointer and bezel driven index, tear drop extension piece, all under heavy bevelled glass.

The conventional Vidie pattern movement mainly constructed in aluminium driven from a single 3” capsule and tensioned on a C spring, set on three spacers and secured on smooth headed threaded pins. The whole contained within a substantial cast, spun, drum form aluminium case.

Presented in its bespoke circular green baize lined mahogany transport case, the inner lid with original calibration chart compiled by hand in ink by Edward Whymper, dated 10 December 1904. Twin securing hooks and keepers.

Condition: The subject of a full service, conservation, and calibration under laboratory conditions, see performance chart from dynamic test. The movement working exceptionally well with full and free registration across the scale. Comparison between the calibration chart of 1904 and that compiled in 2024 shows minimal drift, notwithstanding inherent hysteresis over the period of testing.

The dial with minor marks to centre visible only in certain incident light, some light ageing to periphery of altimetric scale. The glass undamaged. The aluminium case with light oxidation (greying), minor marks and haze to original finish. The timber transport case structurally sound, some shrinkage cracks, light impressions, and minor abrasions. The baize interior lining with some losses, discolouration and staining, otherwise retaining good colour and integrity. The calibration chart legible though aged, abraded and with some staining.

Comments: This substantial barometer was almost certainly supplied as a special order and may well be unique, as no other such instruments of this type have been recorded or observed. Whymper made the last of his trips to the Canadian Rockies in the summer of 1905, and it is most likely that this instrument was commissioned by him to be taken on that expedition.

The choice of instrument by Whymper is interesting. At the time there were smaller instruments available, supplied with loupes or magnifiers, which enabled a more accurate interpretation of values from the dial. This instrument approaches the problem by having a much larger than normal dial which means a more open scale, easier and quicker to read and obviating the need for a loupe or a vernier.

It is evident on examination of this instrument that very special care was taken both with design and execution – for instance, great attention to detail was used in the precise placement of the movement in the same plane as the dial, evidenced by the numbering of the brass spacers to their respective positions on the back plate and something I have not previously seen.

The instrument seems originally to have been designed to hang by a suspension loop which was fitted and then removed prior to delivery – witness marks are evident on the outer case and the mounting hole has been filled with a maker’s smooth headed pin along with a corresponding slitted nut identical to those detailed for securing the movement into the case.

The tear drop bezel extension is interesting. This may or may not have been part of the original design, large diameter bezels being a little more difficult to manipulate and the extension a welcome aid to rotation. In any event there is a corresponding slot cut into the lid of the transport case to accommodate this which means that the extension must be set in exactly the right position for the lid to be re-fitted. This would have been an annoyance for the user unable to set the index and replace the lid for a future observation. For this, and for other unusual attributes such as no hinge, just twin hooks, it is likely that the timber case was a one-off design.

These small details all suggest an almost prototype iteration of the design, and fits completely with the hypothesis that this is a unique instrument.

Of equal scientific and historical interest is that Whymper produced his own calibration chart. He is well known for his applied interest and analysis of the Aneroid Barometer – he authored the 1891 John Murray publication “How to Use the Aneroid Barometer” – and this is evidence that he not only had the equipment to run such a test, or access to such equipment, but also that he may not have wished to rely on any certification supplied with the instrument.

So who was the maker? James J. Hicks was well known for retailing the work of other makers. Most compelling though is the striking similarity of the movements found in the Hicks “Watkin Mountain Aneroid” of 1898 and in this instrument. I have long considered that it was Louis Casella that made the Watkin Mountain Aneroid for Hicks – if correct, then this large barometer is the work of Casella.

One thing is certain – this is an instrument of uncompromising quality, very competently engineered and beautifully poised, as well as could be achieved in the day.

Provenance: By descent, thence directly from the family.

Notes on the Fitting of the Instrument to the Timber Transport Case: With the provision of the tear drop extension lever to the bezel enabling single point rotation, the reaction would have been for the instrument to rotate within the case given the friction between bezel and aluminium case. A short spigot is therefore fitted to the lower or main aluminium case at 4 o’clock engaging with a corresponding slot in the timber case, and thereby locking the instrument in place.

Notes on the Use of Aluminium: Although aluminium was a fairly widely known metal in the mid C 19th it was at that time more expensive than gold. The development of more efficient refining processes from the ore during the later half of the C19th, and ultimately by the Bayer process of 1889, enabled wider access to this “wonder” metal. At the time this instrument was constructed, the application of the metal to engineering was still very much in its infancy: it was highly prized, very expensive, and for the specialist only.

The overarching advantage of this material against copper, iron, zinc and tin based metals was of course substantially less weight, lending itself very much to the construction of instruments for explorers, alpinists, aeronauts, and civil engineers. The first instruments made from aluminium from this period must be considered rare in any event, and they are a fascinating commentary on the advances in engineering and technology of the time.

I am fairly certain that such aluminium instrument cases were initially rough cast and then machined, a complex process and one that would probably have been outside the auspices of most instrument makers of the time. The castings would have had to have been specified and then ordered from a specialist foundry, presumably finally machined “in house.” Careful examination of early aluminium instrument cases strongly suggests this, with similar minor flaws in the material found in contemporary air altimeters manufactured by Negretti & Zambra, pocket barometer altimeters manufactured by Short & Mason, and the Watkin Mountain Aneroid mentioned above. Manufacture of these cases from solid billets of aluminium would have been prohibitively expensive, not to mention time consuming.