how do you read the secondary dial?

The smaller dial on the neck usually shows the temperature. It relies on a separate mercury or alcohol thermometer mounted to a silvered scale. You read it independently of the main barometer face. It just gives you the current room temperature, not a weather forecast.

My grandfather left me this old wall barometer and I was wondering why the glass tube at the back has a big bubble in the middle of it?

That bubble means air has entered the mercury column. The vacuum at the top of the tube is compromised, stopping the instrument from registering pressure changes correctly. A specialist needs to empty the tube, clean the glass and refill it under a vacuum. Do not attempt to fix it yourself, as handling mercury requires specific safety equipment.

what does the knob at the bottom do?

Turning the knob moves the set hand. You align this brass pointer with the main steel indicator. Check back later to see if the steel hand has moved.

I recently bought a barometer with a dark wooden case but I am having trouble getting it to sit flush against the wall because of a bulging piece of wood on the back.

That bulge is a turned wooden cistern cover. It protects the glass reservoir at the base of the tube. Most cases have a hole at the top for a fixing screw. You let the instrument hang freely from that point, and the cistern cover acts as a natural spacer against the wall.

Home > Barometers > Walnut Barometers > Page 2

Antique Walnut Barometers

← Page 2 of 2 →

Designed to measure atmospheric pressure and forecast approaching weather changes, an antique walnut barometer is a wall-mounted scientific instrument housed within a tall, veneered timber case.