Large colliery barometer with painted brass 8″ dial marked 27–33 inches of mercury, the upper part bearing the legend “Hennessy, Swansea,” the maker/retailer, the lower portion marked “Colliery Barometer” and set with large curved mercurial thermometer having a scale of 20-120 degrees Fahrenheit. Heavy blued-steel pointer, substantial bevelled glass having gilt brass telltale to centre with adjustment wheel. Brass bezel with patinated finish, silvered inner ring. The case of original japanned finish with three radially-mounted fixing tabs, the rear with heavy brass movement fixing ferrules, compensation adjustment screw.
A rare piece of our industrial heritage dating from the late 19th century. Bearing in mind its origin and service life, this aneroid barometer has survived in excellent condition and working order.
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.
Bernard Rudkin Hennessy is recorded as working at 5 Wind Street, Swansea from 1841-1875 as a clockmaker, scientist, gunsmith and optician, as well as a shipping magnate (he owned for a while the iron sailing vessel 3-masted barque Atlantic). He is noted in Peates, Iorwerth Clock and Watch Makers in Wales as a contractor to the admiralty, and was a maker of nautical instruments, including chronometers, barometers and sextants.
Dimensions: 8″ diameter x 2¾” deep
Stock No: BA0233
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