Sir Humphry Davy (1778–1829)

Humphry Davy was a distinguished scientist who changed coalmining with his design for a safety lamp. As a scientist he was a pioneer of electrolysis and the first chemist to isolate many elements, including potassium, chlorine, calcium and magnesium. He identified the potential use of nitrous oxide in anaesthesia. He was the first person to demonstrate the principle of the arc lamp. He was also a mentor to the scientist Michael Faraday.

Davy was born in Penzance, as the south-west end of England, where his father worked as a woodcarver. He was apprenticed to a local surgeon, in whose drug dispensary he began to experiment in chemistry. He learned French so that he could study the work of Lavoisier. He showed exceptional ability and in 1798 he was appointed to an institute for the study of gases at Bristol. He got to know other scientists and innovators, including Josiah Wedgwood and James Watt. In 1801, he joined the newly established Royal Institution in London, where he became Professor of chemistry. He was President of the Royal Society and elected to the Royal Swedish Academy of Sciences and the American Academy of Art and Sciences. He was knighted in 1812.

Explosions were a great danger in coal mines. They occurred especially when methane mixed with air was ignited by the candles miners used to light their work. In 1815, the Sunderland Society for the Prevention of Accidents in Coalmines asked Davy if he could solve the problem after a disaster in north-east England killed 92 men. He began experiments in his laboratory to test mine gas. A few months later he presented a paper to the Royal Society and demonstrated a successful lamp.

His safety lamp was an oil lamp. The principle was to prevent the conduction of heat or flame to the gas outside. He improved his invention in December 1815 by using a wire gauze to enclose the flame. The wire let out light but absorbed heat so that gas outside would not reach ignition point. Although gas was sucked inside by the flame, it was not enough to cause an explosion. His lamp was also a warning device: the flame would change colour if methane was present, or if the mine was short of oxygen it would die down.

Others had been experimenting with lamps and some claimed that Davy had copied the idea from the doctor W. R. Clanny or the engineer George Stephenson. However, Davy’s lamp was based on scientific principles. Davy refused to apply for a patent and safety lamps were used widely. The risk of explosion was much reduced but accidents continued as the coalmining industry grew and extended to more dangerous workings.