Negretti & Zambra Fortin-pattern mercury barometer · 1870s
London Fortin mercury barometer in mahogany cabinet. Mercury intact, reads within 0.5mb of modern reference.
- SKU
- MS-SC-1004
- Era
- Pre-1900
- Condition
- Mercury column intact, cabinet re-french-polished 2018, ivory Vernier scale unrestored
- Dimensions
- 38" tall × 4.5" wide
- Weight
- 8 lbs 4 oz
- Provenance
- Ex-collection of a Norfolk yacht club, decommissioned 2017
- Category
- Scientific Instruments
- Tags
- barometermercurynegretti-zambrafortinvictorian
A Negretti & Zambra Fortin-pattern mercury barometer in a mahogany cabinet, London, dated to the 1870s by the ivory Vernier scale style. The mercury is intact and reads within 0.5 mb of a modern reference. Sensitive enough to register a passing train two blocks away.
Fortin's design places the mercury cistern in a leather-bottomed reservoir with a screw adjuster, allowing the meniscus to be brought precisely to the fiducial point of an ivory index — the small detail that separates a meteorological instrument from a piece of furniture. The scale is graduated in both inches and millibars, and the maker's signature is engraved just above the thermometer.
The cabinet was re-french-polished in 2018 by a Norfolk restorer; the Vernier scale, thermometer, and mercury are all as they left Cornhill 150 years ago.
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