How to move a banjo barometer safely?

You need to plug the mercury tube before moving the instrument. Most antique banjo barometers have a small wooden plug tied to the back board for this purpose. You tip the case gently to a forty-five degree angle until the mercury reaches the top of the tube, then push the plug into the open end. Keep the barometer at an angle while carrying it. If you keep it upright without a plug, the mercury will bounce and smash the glass tube. Laying it flat causes air bubbles to enter the mercury column, which stops it reading pressure correctly.

I want to buy one for my hallway but my walls get damp during the winter, will that damage the mechanism?

Damp walls cause serious problems for the wooden case. The carcase is usually pine, which absorbs moisture from the plaster and swells. This swelling forces the mahogany or rosewood veneers to split and peel away from the front of the instrument. Moisture also degrades the silvered dials. The brass oxidises under the silvering, turning the bright surface black and making the numbers hard to read. You should hang the barometer on an internal wall away from direct heat sources and damp patches to keep it functioning.

Why is the dial always pointing to rain?

The words engraved on the dial are only a rough guide. Atmospheric pressure changes tell you what the weather is doing, rather than the static numbers on the brass face. Tap the glass gently. If the needle drops, pressure is falling and you can expect wet weather.

The large brass needle on the front dial seems stuck in one place no matter what the weather is doing outside, how do I fix it?

A stuck needle usually means the pulley system behind the dial has failed. The needle sits on a small brass arbor with a groove, holding a silk thread that connects the glass float to a counterweight. Over time, the silk thread snaps or slips off the wheel. Fixing it requires removing the back panel and restringing the pulley mechanism. It is a fiddly job that involves balancing the glass float on top of the mercury column. Many owners leave this task to a clockmaker or specialist restorer.

Home > Barometers > Banjo Barometers > Page 4

Antique Banjo Barometers from the 19th Century

← Page 4 of 4 →

Antique banjo barometers are wall-mounted weather instruments featuring a distinctive shaped wooden case housing a prominent circular dial and a hidden mercury glass tube. They were designed to read atmospheric pressure changes, helping households forecast the weather before stepping out the door.