A good scarce Mining Barometer with bulkhead mounting retailed by Alex Mabon & Sons, Glasgow, manufactured by Short & Mason c1930

Mining Aneroid barometer having 7½” silvered and machine engraved dial, the barometric scale calibrated in inches of mercury with a range from 27” – 33” divided down to 1/20”, the upper part marked “Mining Barometer,” the lower signed by the retailer “Alex Mabon & Sons, Glasgow.” Silvered reflector ring. Semi circular thermometer calibrated in degrees Fahrenheit, with a range from 20° – 130° divided to 2°. Blued steel pointer and lacquered brass index under bevelled glass.

Conventional grey painted (rust inhibited) Vidie pattern movement driven from a single soldered 2⅞” capsule tensioned on a C spring, plated cock and spindle assembly. All contained within a japanned zinc drum form case fitted with two mounting plates, calibration port to verso.

Condition: The subject of a full service, conservation, and calibration under laboratory conditions, see performance chart from dynamic test. The movement working well with good sensitivity and progression. The dial crisp, very slight marks to outer edge, the reflector ring clear, the finish to case with losses and wear commensurate with age and use, bruise to outer rim at two o’clock.

In completely original condition.

Comments: Alex Mabon & Sons were the leading supplier of mining instruments in Scotland in the early 20th century, carrying a range of high quality instruments including theodolites and surveyors compasses. These mining aneroid barometers are hard to find – we see perhaps one every two years or so – and condition and originality, as always, is all. This instrument is a scarce survivor.

Colliery, Mining or Pit Barometers were made specifically for use in mines from early in the 19th century, with a higher reading scale than above ground barometers. In 1872, an Act of Parliament was passed making their use compulsory. Records clearly showed that before an explosion in a coal mine there had been a diminution of atmospheric pressure. The Act required a barometer to be placed above ground in a conspicuous position near the mine entrance but they were always made of solid construction so they could also be used underground. With the scale going up to 33″ the barometer could be used at least 2,000 feet below sea level.