Davy Lamps

Two safety lamps, Davy, the first to be used in a coal mine, 1815.

These are the first safety lamps to be used in a coal mine, and was made by Sir Humphrey Davy. Before the safety lamp’s invention, miners would use candles or other naked flames, which carried a serious risk of causing explosions due to the presence of ‘firedamp’ – methane gas diluted with air - which resulted in heavy loss of life. From 1813, efforts were made to provide a safer form of light underground, in which Davy and George Stephenson were prominent. There has been a long controversy over which of the two men was first in making a safety lamp. However, Davy’s lamp was most significant because of his understanding of the scientific principles underpinning its safe design. It employed a fine wire gauze to surround the flame but let light out, Davy having established through experiments that explosive firedamp mixtures would not pass through such small apertures. For the reason of Davy's experimental approach, the lamp has also been described as one of the very first examples of technology as applied science.

The attention of Humphrey Davy was drawn, in 1815, to the subject of lighting fiery mines; as the outcome of his investigations he found that perforated metal or wire gauze will so cool a flame attempting to pass through it as to prevent ignition of an external inflammable mixture. Davy's original experimental lamp is preserved at the Royal Institution, but the two oil lamps shown are the first actually used in a coal mine. To the upper part of the oil reservoir is screwed a cylinder of brass wire gauze, 1.5 in. diam. by 5 in. high, of 6,400 apertures to the sq. in. (i.e., a much finer gauze than was afterwards used). Three rods, forming a cage to protect the gauze, are fixed to the cylinder at the bottom and to a plate at the top, in which is a carrying ring. In one case the oil reservoir and the gauze are of the same diameter, and the lamp weighs 0.3 lb. In the other case the reservoir is larger than the gauze, has a pricker to turn the wick, and is filled by an external spout; this lamp is probably of a later date than the other, and weighs 0.43 15.