Lot 713 - 07 Nov 2017
Autumn Fine Auction
A late Victorian oak and brass-mounted Miner's or Pit-head stick barometer
By Negretti & Zambra, London, circa 1890
The plain case with an arched pediment, above a glazed brass surround with silvered plates, signed 'NEGRETTI & ZAMBRA LONDON', and fitted with a thermometer, the trunk with canted angles
90.5cm high. Illustrated
These were used in determining the risks from inflammable and suffocating gases, known to miners as 'firedamp' and 'choke damp'. As the gas was heavier than air, and combined with a drop to low atmospheric pressure, it would be driven to the lowest and least ventilated galleries.