A barometer is a device that measures air (barometric) pressure. It measures the weight of the column of air that extends from the instrument to the top of the atmosphere. There are two types of commonly-used barometers, mercury and aneroid (meaning "fluidless") .

What a Barometer Does

A barometer measures present air pressure, that is the weight of air above it at any one time. As Admiral Fitzroy once described, the air around us can be thought of as an ocean in which we live. The higher you go in the air, such as up a mountain, the thinner the air becomes and the less the air pressure is. So your barometer will normally need setting for the altitude where it is going to finally hang. For domestic barometers this is usually only of any importance to set within 1-200 feet of accuracy.

All our barometers come with instructions and our skilled staff are normally available to help if needed.