English Scientific Barometer cica 1850

A rare mid-nineteenth century scientific barometer with a large diameter tube and a movable scale so that the zero position may be accurately set to the level of mercury in the short limb.  The barometer and a thermometer are mounted on a mahogany backboard.

The barometer has a tube, of constant bore throughout its length, of approximately 1 inch diameter and the lacquered brass scale is graduated from 27 to 31 inches of mercury.  The vernier and travelling microscope enable the pressure to be read to an accuracy of 0.002 of an inch.  The moveable scale, with rack and pinion adjustment enables the scale zero position to be accurately set.

The silvered thermometer scale is graduated from 0 to 130degrees Fahrenheit. The instrument has a replacement barometer tube, and a replacement thermometer tube.

The mahogany backboard on which the barometer and thermometer are mounted is hinged to a second mahogany board so that the screws into the wall are concealed.

The barometer is shown in the photographs without mercury as it is not possible to transport this barometer when filled.

The barometer has been restored.

(Stock No. C958)