Late Victorian Oak Miner's or Pit Head Stick Barometer by Negretti & Zambra
A late Victorian oak miners or pit head barometer by Negretti & Zambra.
The barometer is comprised of a solid oak case with enclosed a silvered scale, single vernier and brass surround. They were manufactured by Negretti & Zambra as early as 1864, however their use for mining was made compulsory by an act of parliament in 1872. It was understood by this point that a mine explosion was preceded by a corresponding reduction of atmospheric pressure so these instruments had a very real safety purpose for those working in the harsh conditions of a mine.
Section 26 of the Mines (Coal) Regulations Act of 1872 stated that, “After dangerous gas has been found in any mine, a barometer or thermometer shall be placed above ground in a conspicuous position near the entrance to the mine.”
In fact, these barometers were commonly taken underground and this is evidenced from the size of the scale of these barometers, reading from 26 to 33 inches allowing for the barometer to be used at 2000 feet below sea level.
Negretti & Zambra in their “Treatise on Meteorological Instruments” state the following: “The inflammable & suffocating gases, known to coal miners as fire damp and choke damp, are specifically heavier than air; and as they issue from the fissures of the mine, or are released from the coal, the atmospheric pressure tends to drive them into the lowest and least ventilated galleries. Consequently a greatly reduced atmospheric pressure will favour a sudden outflow or advance of gas; whence may result cases of explosion or suffocation. It has been found that these accidents occur for the most part about the time of a low barometric column. A reliable barometer should, therefore, be systematically consulted by those entrusted with the management or control of coal mines, so that greater vigilance and caution may be enjoined on the miners whenever the mercury falls low, especially after it has been unusually high for some days.”
This relic from Britain’s industrial past is both an interesting historical piece and a very smart looking barometer in superb condition and in good working order.
Circa 1880 - 1900