Barometers Realm

One-third of the instrument’s structure is dominated by a rotating bezel, a feature as practical as it is visually captivating. The bezel holds a flat glass with beveled edges, a detail that catches and plays with light, enhancing the sense of depth and precision. Beneath the glass lies a silvered brass altitude scale, calibrated up to 6000 feet — a range that speaks to the adventurous spirit of its era. The scale is adorned with a finely engraved trend indicator in the form of a bold, sweeping arrow, its presence a subtle yet striking guide for interpreting atmospheric conditions.

The dial, also made of silvered brass, is a study in minimalist elegance. Its semi-circular barometric scale, spanning from 24 to 31 inches of mercury, provides clear and precise readings. The sparse meteorological terms, "RAIN" and "FAIR," etched in uppercase letters with shadowed contours, convey a sense of simplicity and directness, prioritizing functionality while retaining an aesthetic charm. Callaghan’s name is engraved in a similarly bold style, asserting the artisan’s reputation, while the workshop’s address, inscribed in flowing cursive with a mix of upper and lowercase letters, adds a refined contrast, grounding the instrument in its London origins.

A delicate steel pointer, blued to a deep, almost luminous finish, traverses the dial with precision. Its crescent-shaped fletching not only adds a decorative touch but also enhances visibility, a practical nod to its intended use in varying conditions. The barometer’s brass suspension ring ensures it can be securely fastened or displayed, adding versatility to its design.

Completing this piece is a leather case, remarkably preserved and as functional as it is protective. The case encapsulates the barometer’s portability, offering both security and an additional layer of craftsmanship that underscores the instrument’s premium nature.

William Callaghan (1817–1874) was an optician from London, England. He worked for Thomas P. Harris, and the 1841 Census lists him as an optician’s apprentice in Harris’s household. By 1845, he was trading at 45 Great Russell Street, Bloomsbury. He sold spectacles, octants, telescopes, perspective glasses, and microscopes, as well as opera, marine, field, and race glasses. Callaghan advertised himself as the sole agent for Voigtländer opera glasses and race glasses, and during the 1860s, he also represented Voigtländer portrait and landscape photographic lenses.

In 1855, he announced in The Times that he had relocated to 23a New Bond Street, where he conducted business until his death in 1874. After his death, the business was inherited by his son, William Edmund Callaghan (c.1853–1890), who in 1875 obtained freedom from the Spectacle Makers’ Company by purchase. He continued his father’s business, and by 1877, the company was advertising under the name Callaghan & Co. His son, Edmund Ford Callaghan (c.1880–1946), was also a manufacturer and dealer in optical instruments and continued the business at 23a New Bond Street until at least 1909.