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T166-25 · Pocket
early 20th century
Object Overview
This pocket barometer featuring a thermometer dates from the early 20th century and was produced by James Joseph Hicks, one of London’s foremost manufacturers of scientific and meteorological instruments.
The 5 cm case is made of gilt brass and fitted with a suspension ring. The rotating fluted bezel features a rarely seen domed mineral glass with a faceted edge — an uncommon detail in pocket aneroids. On the inner side of the bezel is a fine steel pointer, which functions as a trend indicator hand.
The dial is made of silvered brass and laid out in concentric circles: the inner circle shows atmospheric pressure in inches, comparable to a mercurial column (ranging from 18 to 31), while the outer circle gives altitude in feet, up to a maximum of 15,000.
In the recessed central part of the stepped dial are engraved three weather indication terms. The words RAIN and FAIR are rendered in bold letters with broad strokes and decorative serifs, evoking a 19th-century signage aesthetic. The word CHANGE is executed in a stylized, slightly Gothic script: the initial letter is ornate and almost manuscript-like, while the remaining letters are sharp, slanted, and uneven in stroke width, as if handwritten in ink.
7794
aneroid capsule tensioned on a C-spring
brass, glass, silvered brass, steel
The stepped dial design is not merely decorative — it accommodates a miniature curved mercury thermometer, calibrated in degrees Fahrenheit. The bulb reservoir of the thermometer is recessed into the case and protected beneath the dial plate.
The barometer mechanism is based on a conventional movement tensioned on a C-spring. Temperature compensation is achieved by means of a robust bi-metallic plate, created by milling off half the thickness of the primary lever and replacing the brass layer with an equal thickness of steel — a method known as the bi-metallic link system.
This finely crafted instrument combines precision engineering with elegant detailing, making it a notable example of British pocket meteorological design.