English Banjo barometer

Description

Barometer, made by D. Albino in Cheltenham, c. 1840

Case
The mahogany-veneered pine case is of classic design, hence the name wheel or banjo barometer. It is a so-called five-dial barometer, the dials all being silvered. At the top there is a hygrometer, going down a removable alcohol thermometer, followed by a butler mirror and the main dial, with a spirit level at the bottom, signed by the maker: D. Albino Cheltenham. At the back there is a long door giving access to a Torricelli tube. The swan-neck top has a vase-shaped finial.

Register plate
Within the case there is a Torricelli tube which registers the air pressure. There is a float on top of the mercury level, connected to a pulley with a counter weight on the other side. The pulley arbor is connected to a pierced blued-steel central sweep hand on the barometer scale. In this way a small difference in air pressure is made visible on the large silvered register plate (main dial 28-31). The weather conditions are indicated along the various pressures on the scale. The brass setting hand can be moved by turning a bone knob below the barometer scale. The alcohol thermometer has a silvered brass register plate divided in degrees Fahrenheit, whilst the hygrometer indicates the humidity with the words dry and
damp.