How do these barometers work?

A sealed glass tube filled with mercury responds directly to changes in atmospheric pressure, causing the column to rise or fall. In wheel instruments, a float resting on the mercury connects to a pulley that turns a pointer around a graduated dial.

Where were these instruments made?

Makers worked in workshops across London as well as provincial towns and cities throughout England, Scotland and Ireland. Many practitioners originated from Italian immigrant families who settled in British urban centres to practice instrument making.

How do I hang a wall barometer?

These instruments require secure mounting from a heavy brass ring or bracket attached firmly to the upper backplate. Because the internal mercury tube is sensitive to alignment, the case must hang plumb against a stable wall surface.

How do I identify the period?

Stylistic details in the timber case, such as shell inlay, pediment shapes and dial designs, point to specific decades. Signatures engraved on the metal dial plates often allow direct identification of the maker and their working dates.