Humphry Davy

Humphry Davy (1778 - 1829) was a British chemist and inventor who pioneered the use of electrolysis to isolate chemical elements, discovering potassium, sodium, calcium, magnesium, barium and strontium, and who devised the miner's safety lamp that bears his name.^[1]

Early life and education

Davy was born on 17 December 1778 in Penzance, Cornwall. After schooling that included Truro Cathedral School, he was apprenticed to a local surgeon-apothecary, an arrangement through which he began teaching himself chemistry.^[2] In 1798 he joined the Pneumatic Institution in Bristol, where he investigated the physiological effects of recently discovered gases and observed the intoxicating and pain-dulling properties of nitrous oxide.

The Royal Institution and electrochemistry

In 1801 Davy was appointed to the Royal Institution in London, where his vivid public lectures made him one of the most celebrated scientific figures of his day. Using the powerful voltaic battery assembled there, he became a pioneer of electrochemistry, passing electric current through molten compounds to break them apart.

Isolation of the elements

This method yielded a remarkable series of discoveries. In 1807 Davy isolated potassium and sodium for the first time, and in 1808 he obtained calcium, magnesium, barium and strontium. He also demonstrated that chlorine was an element in its own right rather than a compound, and he studied the newly identified iodine. These results confirmed the elemental nature of many substances and helped establish electrochemistry as a discipline.

The Davy lamp

In 1815 Davy addressed a pressing practical problem: the frequent explosions caused by firedamp in coal mines. He designed a safety lamp in which the flame was enclosed by a fine wire gauze that conducted away heat and prevented the ignition of flammable gas. The Davy lamp saved many lives, and he declined to patent it so that it could be used freely.^[3]

Legacy

A Fellow of the Royal Society, Davy served as its President from 1820 and received leading honours of his era, including the Copley, Rumford and Royal Medals. At the Royal Institution he employed and mentored the young Michael Faraday, who would become one of the greatest experimental scientists of the nineteenth century. In declining health, Davy travelled on the Continent and died in Geneva on 29 May 1829.