The setting or recording aneroid barometer with 3¼” transfer decorated enamel dial, calibrated in inches of mercury with a range from 27 – 31” with stations on the inch and divided to 20ths. The inner part marked with standard meteorological terms “Stormy, Rain, Change, Fair, Very Dry.” The upper part detailed with retailer’s name, “S.C. Tisley & Co,” the lower part marked “London” and, in script, “Aneroid Barometer.”
Early pattern movement driven from a 2” capsule and tensioned on a coil spring. Blued steel pointer, gilt brass index, all set in a gilt brass surround and recessed within a silvered facia, the lower part marked across the top with first letters for days of the week and vertically to the sides with a descending pressure scale from 31 to 29 inches of mercury. High polished silvered frame returns, convex section ormolu surround maintaining a single glass. Seven horizontally arranged rack and pinion vertical brass extending indicator rods, set to correspond with days and positioned from a series of corresponding knobs set below.
All contained within an ebonised oak case, classically mid-Victorian transport handle to top, the whole raised on a moulded plinth with inverted conical bright-plated cast brass feet. The verso with opening door on a catch affording access to the barometer and adjustment port.
Condition: The barometer dial damage free, clear and crisp. The facia retaining virtually all its original silvered finish. The rack and pinion pressure indicators move freely. The barometer performing well within reasonable parameters with good sensitivity and progression, see performance chart below. The timber case structurally sound though noticeably off square when viewed directly from the front. Retains a very good proportion of its original ebonised finish.
The subject of a near complete re-build and re-calibration, tested and calibrated under laboratory conditions. Overall, this is a good, clean and very original instrument in excellent working order.
Comments: We know of three of these instruments only, and this is one of the most extraordinarily interesting meteorological instruments encountered. Clearly made in very small numbers, and almost certainly as a party to the manufacture of drum barograph recorders which at this time were just appearing. The question has to be asked, why were there not more of them? One answer might be that they would not have been cheap, but in any event they clearly required some discipline by the owner to faithfully record the day’s pressure. The idea of the instrument is very sound, the practical operation of it, less than convenient – the drum barograph recorder a much more practical proposition.
It seems likely, based on the two instruments examined, that they were made in France for the English market. Dials and major castings are numbered – we have seen No 4 and No 8, the third example I mention is unknown. This instrument would clearly have been a cheaper alternative to a drum barograph recorder and, with a little conjecture, it might be that they were more a marketing exercise aimed at parochial opticians where the clientele might be more easily persuaded as to the instrument’s merits. This instrument is marked to the dial with the retailer’s details “S.C. Tisley & Co, London” – the other I have examined is marked “Hallett, Hastings.”
S.C. Tisley & Co was a manufacturer and retailer of scientific instruments, particularly globes.
Probably on the same level as the Atmos Barometer (though the Atmos was essentially just a barometer), this instrument stands as representatively most important as a creation born of the infancy of forecasting. They may both, though, have something of the synergy of the drum barograph recorder.
Without doubt a most important collector’s piece. Not unique but extremely rare.
Dimensions: 6” wide x 9” high x 3½” deep
Stock No: BA1665
Price: £ 1850