Sir Humphry Davy, 1st Baronet, FRS (17 December 1778 – 29 May 1829) was a British chemist and physicist. He was born in Penzance, Cornwall, United Kingdom and both his brother John Davy and cousin Edmund Davy were also noted chemists. Berzelius called Davy's 1806 Bakerian Lecture "On some Chemical Agencies of Electricity" "one of the best memoirs which has ever enriched the theory of chemistry."

Biography
In 1812 he was knighted, gave a farewell lecture to the Royal Institution, and married a wealthy widow, Jane Apreece. While generally acknowledged as being faithful to his wife, their relationship was stormy and in his later years Davy travelled to continental Europe alone. In October 1813 he and his wife, accompanied by Michael Faraday as his scientific assistant (and valet) traveled to France to collect a medal that Napoleon Bonaparte had awarded Davy for his electro-chemical work. Whilst in Paris Davy was asked by Gay-Lussac to investigate a mysterious substance isolated by Bernard Courtois. Davy showed it to be an element, which is now called iodine. The party left Paris on December 29, travelling south through Montpellier and Nice and then to Italy.
After passing through Genoa, they went to Florence, where, in a series of experiments starting on Sunday March 27, Davy, with Faraday's assistance, succeed in using the sun's rays to ignite diamond, and proved that it was composed of pure carbon. Davy's party continued on to Rome, and also visited Naples and Mount Vesuvius. By the June 17, they were in Milan, where they met Alessandro Volta, and continued north to Geneva. They returned to Italy via Munich and Innsbruck, passed though Venice and returned to Rome. Their plans to travel to Greece and Constantinople (Istanbul) were abandoned after Napoleon's escape from Elba, and they returned to England.

Retirement and further work
After his return to England in 1815, Davy went on to produce the Davy lamp which was widely used by miners. Although the idea of the safety lamp had already been demonstrated by William Reid Clanny and an engineer, George Stephenson, his use of wire gauze to prevent the spread of flame was quickly copied by both of these inventors in their later designs.

Discovery of chlorine
In 1815 Davy suggested that acids were substances that contained replaceable hydrogen – hydrogen that could be partly or totally replaced by metals. When acids reacted with metals they formed salts. Bases were substances that reacted with acids to form salts and water. These definitions worked well for most of the century. Today we use the Brønsted-Lowry theory of acids and bases.
In 1818, he was awarded a baronetcy and two years later he became President of the Royal Society.

Acid-base studies
Davy died in Switzerland in 1829, his various inhalations of chemicals finally taking its toll on his health. He is buried in the Plain Palais Cemetery in Geneva.
Davy's laboratory assistant, Michael Faraday, went on to enhance Davy's work and in the end became more famous and influential – to such an extent that Davy is supposed to have claimed Faraday as his greatest discovery. However, he later accused Faraday of plagiarism, causing Faraday (the first Fullerian Professor of Chemistry) to cease all research in electromagnetism until his mentor's death.

Death

A lunar crater is named after Sir Humphry Davy. It has a diameter of 34 km and coordinates of 11.8S, 8.1W.
In Penzance in Cornwall, Davy's hometown, there is a statue of him in front of the imposing Market House, now owned by Lloyds TSB, at the top of Market Jew Street, the town's main high street. There also is a secondary school in Penzance named Humphry Davy School. Like James Prescott Joule and Isaac Newton, Davy is remembered in his hometown by a pub. The Sir Humphry Davy pub is located in Penzance opposite the Geenmarket at the end of Market Jew Street.
Davy was the subject of the first ever clerihew.
A satellite of the University of Sheffield at Golden Smithies Lane in Wath upon Dearne (Manvers) is called Humphry Davy House and is currently home to the School of Nursing and Midwifery, until April 2009. Writings by Davy