Humphry Davy

Sir Humphry Davy (1778 to 1829) was a British chemist, physicist and inventor, born in Penzance, Cornwall. Apprenticed to an apothecary at seventeen, he was appointed at twenty to run the laboratory of the Medical Pneumatic Institution in Bristol, where he found the intoxicating effects of nitrous oxide, and he was then invited to the Royal Institution in London, where his popular chemistry lectures made his name. In 1807 he used one of the most powerful voltaic batteries of the day to decompose potassium and sodium salts by electrolysis, isolating both metals, and the next year he isolated calcium, magnesium, barium and strontium. He showed that chlorine is an element and that acids depend on hydrogen rather than oxygen, and in 1810 he produced an arc light between carbon poles. After 1815 he invented the Davy lamp, a miners safety lamp that encloses the flame in fine wire mesh so that it cannot ignite firedamp, a claim George Stephenson later challenged. In 1824 he proposed cathodic protection for copper-clad ship hulls by mounting iron on them. Knighted in 1812 and made a baronet in 1818, he presided over the Royal Society until 1827 and was the mentor of Michael Faraday.