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Humphry Davy

[dey-vee]

Sir Humphry Davy, 1st Baronet FRS MRIA (17 December 1778 – 29 May 1829) was a British chemist and inventor. He is probably best remembered today for his discoveries of several alkali and alkaline earth elements, as well as contributions to the discoveries of the elemental nature of chlorine and iodine. He invented the Davy lamp, which allowed miners to enter gassy workings. 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. This paper was central to any chemical affinity theory in the first half of the nineteenth century.

Biography

Davy was born at Penzance in Cornwall on 17 December 1778. The parish register of Madron (the parish church) records ‘Humphry Davy, son of Robert Davy, baptized at Penzance, January 22nd, 1779.’ Robert Davy was a wood-carver at Penzance, who pursued his art rather for amusement than profit. As the representative of an old family (monuments to his ancestors in Ludgvan Church date as far back as 1635), he became possessor of a modest patrimony. His wife, Grace Millett, came of an old but no longer wealthy family. Her parents died within a few hours of each other from malignant fever, when Grace and her two sisters were adopted by John Tonkin, an eminent surgeon in Penzance. Robert Davy and his wife became the parents of five children—two boys, Humphry, the eldest, and John, and three girls. In Davy's childhood the family moved from Penzance to Varfell, their family estate in Ludgvan. Davy's boyhood was spent partly with his parents and partly with Tonkin, who placed him at a preparatory school kept by a Mr. Bushell, who was so much struck with the boy's progress that he persuaded the father to send him to a better school. Davy was at an early age placed at the Penzance grammar school, then under the care of the Rev. J. C. Coryton. Numerous anecdotes show that Davy was a precocious boy, possessing a remarkable memory and being singularly rapid in acquiring knowledge of books. He was especially attracted by the ‘Pilgrim's Progress,’ and he delighted in reading history. When but eight years of age he would collect a number of boys, and standing on a cart in the market-place address them on the subject of his latest reading. He delighted in the folklore of this remote district, and became, as he himself tells us, a ‘tale-teller.’ The ‘applause of my companions,’ he says, ‘was my recompense for punishments incurred for being idle.’ These conditions developed a love of poetry and the composition of verses and ballads.

At the same time Davy acquired a taste for experimental science. This was mainly due to a member of the Society of Friends named Robert Dunkin, a saddler and a man of original mind and of the most varied acquirements. Dunkin constructed for himself an electrical machine, voltaic piles, and Leyden jars, and made models illustrative of the principles of mechanics. By the aid of these appliances he instructed Davy in the rudiments of science. As professor at the Royal Institution, Davy repeated many of the ingenious experiments which he had learned from his quaker instructor. From the Penzance school Davy went in 1793 to Truro, and finished his education under the Rev. Dr. Cardew, who, in a letter to Davies Gilbert, says: ‘I could not discern the faculties by which he was afterwards so much distinguished.’ Davy says himself: ‘I consider it fortunate I was left much to myself as a child, and put upon no particular plan of study. … What I am I made myself.’

Apprentice and poet

After the death of Davy's father in 1794, Tonkin apprenticed the boy to John Bingham Borlase, a surgeon in large practice at Penzance. Davy's indenture is dated 10 February 1795. In the apothecary's dispensary Davy became a chemist, and a garret in Tonkin's house was the scene of his earliest chemical operations. Davy's friends would often say: ‘This boy Humphry is incorrigible. He will blow us all into the air,’ and his eldest sister complained of the ravages made on her dresses by corrosive substances.

Much has been said of Davy as a poet, and John Ayrton Paris somewhat hastily says that his verses ‘bear the stamp of lofty genius.’ Davy's first production preserved bears the date of 1795. It is entitled ‘The Sons of Genius,’ and is marked by the usual immaturity of youth. The poems, produced in the following years, especially those ‘On the Mount's Bay’ and ‘St. Michael's Mount,’ are pleasingly descriptive verses, showing sensibility, but no true poetic imagination. Davy soon abandoned poetry for science. While writing verses at the age of seventeen in honour of his first love, he was eagerly discussing with his Quaker friend the question of the materiality of heat. Dunkin once remarked: ‘I tell thee what, Humphry, thou art the most quibbling hand at a dispute I ever met with in my life.’ One winter day he took Dunkin to Larigan river, to show him that the rubbing of two plates of ice together developed sufficient energy by motion to melt them, and that the motion being suspended the pieces were united by regelation. This was, in a rude form, an elementary version of an analogous experiment later exhibited by Davy in the lecture-room of the Royal Institution, which excited considerable attention.

Early scientific leanings

Davies Giddy, afterwards Davies Gilbert, accidentally saw Davy in Penzance, carelessly swinging on the half-gate of Dr. Borlase's house. Gilbert was interested by the lad's talk, offered him the use of his library, and invited him to his house at Tredrea. This led to an introduction to Dr. Edwards, who then resided at Hayle Copper House, and was also chemical lecturer in the school of St. Bartholomew's Hospital. Dr. Edwards permitted Davy to use the apparatus in his laboratory, and appears to have directed his attention to the floodgates of the port of Hayle, which were rapidly decaying from the contact of copper and iron under the influence of seawater. This galvanic action was not then understood, but the phenomenon prepared the mind of Davy for his experiments on the copper sheathing of ships in later days. Gregory Watt, the son of James Watt, visited Penzance for his health's sake, and lodging at Mrs. Davy's house became a friend of her son and gave him instructions in chemistry. Davy also formed a useful acquaintance with the Wedgwoods, who spent a winter at Penzance.

Thomas Beddoes and Professor Hailstone were engaged in a geological controversy upon the rival merits of the Plutonian and the Neptunist hypotheses. They travelled together to examine the Cornish coast accompanied by Davies Gilbert, and thus made Davy's acquaintance. Beddoes, who had recently established at Bristol a ‘Pneumatic Institution,’ required an assistant to superintend the laboratory. Gilbert recommended Davy for the post, and Gregory Watt placed (in April 1798) in the hands of Beddoes the ‘Young man's Researches on Heat and Light,’ which were subsequently published by him in the first volume of ‘West-Country Contributions.’ Prolonged negotiations were carried on, mainly by Gilbert. Mrs. Davy and Borlase consented to Davy's departure, but Tonkin desired to fix him in his native town as a surgeon, and actually altered his will when he found that Davy insisted on going to Dr. Beddoes.

The Pneumatic Institution

On 2 October 1798 Davy joined the ‘Pneumatic Institution’ at Bristol. This institution was established for the purpose of investigating the medical powers of factitious airs and gases, and to Davy was committed the superintendence of the various experiments. The arrangement concluded between Dr. Beddoes and Davy was a liberal one, and enabled Davy to give up all claims upon his paternal property in favour of his mother. He did not intend to abandon the profession of medicine, being still determined to study and graduate at Edinburgh. However, he soon found his whole energies absorbed in the labours of the laboratory. During his residence at Bristol, Davy formed the acquaintance of the Earl of Durham, who became a resident for his health in the Pneumatic Institution, and of Samuel Taylor Coleridge and Robert Southey. In December 1799 Davy visited London for the first time, and his circle of friends was there much extended.

In this year the first volume of the ‘West-Country Collections’ was issued. Half of the volume consisted of Davy's essays ‘On Heat, Light, and the Combinations of Light,’ ‘On Phos-oxygen and its Combinations,’ and on the ‘Theory of Respiration.’ On 22 February 1799 Davy, writing to Davies Gilbert, says: ‘I am now as much convinced of the non-existence of caloric as I am of the existence of light.’ In another letter written to Davies Gilbert, on 10 April, Davy informs him: I made a discovery yesterday which proves how necessary it is to repeat experiments. The gaseous oxide of azote (the laughing gas) is perfectly respirable when pure. It is never deleterious but when it contains nitrous gas. I have found a mode of making it pure.’ He then says that he breathed sixteen quarts of it for nearly seven minutes, and that it ‘absolutely intoxicated me.’ During this year Davy published his ‘Researches, Chemical and Philosophical, chiefly concerning Nitrous Oxide and its Respiration.’ In after years Davy regretted that he had ever published these immature hypotheses, which he himself subsequently designated as ‘the dreams of misemployed genius which the light of experiment and observation has never conducted to truth.’

The Royal Institution

In 1800 Davy informed Davies Gilbert that he had been ‘repeating the galvanic experiments with success’ in the intervals of the experiments on the gases, which ‘almost incessantly occupied him from January to April.’ In these experiments Davy ran considerable risks. The respiration of nitrous oxide led, by its union with common air in the mouth, to the formation of nitrous acid, which severely injured the mucous membrane, and in his attempt to breathe carburetted hydrogen gas he ‘seemed sinking into annihilation.’ On being removed into the open air he faintly articulated, ‘I do not think I shall die,’ but some hours elapsed before the painful symptoms ceased. It is likely that the nitrous oxide he inhaled was contaminated by nitric oxide, a toxic gas which combines with oxygen to form nitric acid, a very strong acid and irritant, which explains the pain he felt.

Davy's ‘Researches,’ which was full of striking and novel facts, and rich in chemical discoveries, soon attracted the attention of the scientific world, and Davy now made his grand move in life. In 1799 Count Rumford had proposed the establishment in London of an ‘Institution for Diffusing Knowledge,’ i.e. the Royal Institution. The house in Albemarle Street was bought in April 1799. Rumford became secretary to the institution, and Dr. Garnett was the first lecturer. Garnett was forced to resign from ill-health in 1801. Rumford had already been empowered to treat with Davy. Personal interviews followed, and on 15 July 1801 it was resolved by the managers ‘that Humphry Davy be engaged in the service of the Royal Institution in the capacity of assistant lecturer in chemistry, director of the chemical laboratory, and assistant editor of the journals of the institution, and that he be allowed to occupy a room in the house, and be furnished with coals and candles, and that he be paid a salary of 100l. per annum.’ In 1801 he was nominated professor at the Royal Institution of Great Britain and Fellow of the Royal Society, over which he would later preside.

Electrolysis

Davy was a pioneer in the field of electrolysis using the battery to split up common compounds and thus prepare many new elements. He went on to electrolyse molten salts and discovered several new metals, especially sodium and potassium, highly reactive elements known as the alkali metals. Potassium was discovered in 1807 by Davy, who derived it from caustic potash (KOH). Before the 18th century, no distinction was made between potassium and sodium. Potassium was the first metal that was isolated by electrolysis. Sodium was first isolated by Davy in the same year by passing an electric current through molten sodium hydroxide. Sodium quickly oxidizes in air and is violently reactive with water, so it must be stored in an inert medium, such as kerosene. Sodium is present in great quantities in the earth's oceans as sodium chloride (common salt). Davy went on to discover calcium in 1808 by electrolyzing a mixture of lime and mercuric oxide. Davy was trying to isolate calcium; when he heard that Berzelius and Pontin prepared calcium amalgam by electrolyzing lime in mercury, he tried it himself. He worked with electrolysis throughout his life and also discovered magnesium, boron and barium.

Discovery of chlorine

Chlorine was discovered in 1774 by Swedish chemist Carl Wilhelm Scheele, who called it dephlogisticated marine acid (see phlogiston theory) and mistakenly thought it contained oxygen. Scheele produced chlorine by reacting manganese dioxide {MnO₂) with hydrogen chloride (HCl).

4 HCl + MnO₂ → MnCl₂ + 2 H₂O + Cl₂

Scheele observed several properties of chlorine gas, such as its bleaching effect on litmus, its deadly effect on insects, its yellow-green colour, and the similarity of its smell to that of aqua regia. However, Scheele was unable to publish his findings at the time.

In 1810, chlorine was given its current name by Humphry Davy, who insisted that chlorine was in fact an element. He also showed that oxygen could not be obtained from the substance known as oxymuriatic acid (HCl solution). This discovery overturned Lavoisier's definition of acids as compounds of oxygen.

Popular public figure

Sir Humphry revelled in his public status, as his lectures gathered many spectators. He became well known due to his experiments with the physiological action of some gases, including laughing gas (nitrous oxide) - to which he was addicted, once stating that its properties bestowed all of the benefits of alcohol but was devoid of its flaws.

Davy later damaged his eyesight in a laboratory accident with nitrogen trichloride. Pierre Louis Dulong first prepared this compound in 1812, and lost two fingers and an eye in two separate explosions with it. Davy's own accident induced him to hire Michael Faraday as a coworker.

Work

In 1812, Davy 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. While 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 in December of 1813, travelling south to Italy. They sojourned in Florence, where, in a series of experiments conducted with Faraday's assistance, Davy succeeded in using the sun's rays to ignite diamond, proving it is composed of pure carbon. Davy's party continued on to Rome, and also visited Naples and Mount Vesuvius. By June 1814, they were in Milan, where they met Alessandro Volta, and then continued north to Geneva. They returned to Italy via Munich and Innsbruck, and when their plans to travel to Greece and Constantinople (Istanbul) were abandoned after Napoleon's escape from Elba, they returned to England.

In January 1819, Davy was awarded a baronetcy, at the time the highest honour ever conferred on a man of science in Britain. A year later he became President of the Royal Society.

Davy lamp

After his return to England in 1815, Davy experimented with lamps for use in coal mines. There had been many mining explosions caused by firedamp or methane often ignited by open flames of the lamps then used by miners. In particular the Felling mine disaster in 1812 near Newcastle caused great loss of life, and action was needed to improve underground lighting and especially the lamps used by miners. Davy conceived of using an iron gauze to enclose a lamp's flame, and so prevent the methane burning inside the lamp from passing out to the general atmosphere. Although the idea of the safety lamp had already been demonstrated by William Reid Clanny and by the then unknown (but later very famous) engineer George Stephenson, Davy's use of wire gauze to prevent the spread of flame was copied by other inventors in their later designs. Unfortunately, although the new design initially did seem to offer protection, it gave less light, and quickly deteriorated in the wet conditions of most pits. Rusting of the gauze quickly made the lamp unsafe, and the number of deaths from firedamp explosions rose yet further.

There was some discussion as to whether Davy had discovered the principles behind his lamp without the help of the work of Smithson Tennant, but it was generally agreed that the work of both men had been independent. Davy refused to patent the lamp, and its invention led to him being awarded the Rumford medal in 1816.

Acid-base studies

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 nineteenth century.

Death

Davy died in Switzerland in 1829, his various inhalations of chemicals finally taking their 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 he became the more famous and influential scientist – to the extent that Davy is supposed to have claimed Faraday as his greatest discovery. However, Davy later accused Faraday of plagiarism, causing Faraday (the first Fullerian Professor of Chemistry) to cease all research in electromagnetism until his mentor's death.

Legacy and honours

A lunar crater (Davy) 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 Greenmarket 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.

Publications

See Fullmer's work for a full list of Davy's articles. Davy's books are as follows:

Researches, Chemical and Philosophical, Bristol: Biggs and Cottle, 1800
Elements of Chemical Philosophy, London: Johnson and Co., 1812
Elements Of Agricultural Chemistry In A Course Of Lectures, London, Longman, 1813
The Papers of Sir H. Davy, Newcastle: Emerson Charnley, 1816 (on Davy's safety lamp)
Discourses to the Royal Society, London: John Murray, 1827
Salmonia or Days of Fly Fishing, London: John Murray, 1828
Consolations in Travel or The Last Days of a Philosopher by Humphry Davy (1830), London: John Murray, 1830

Bibliography

Davy, John (1839-40). The Collected Works of Sir Humphry Davy. London: Smith, Elder, and Company.
Harold Hartley (1960). "The Wilkins Lecture. Sir Humphry Davy, Bt., P.R.S. 1778-1829". Proceedings of the Royal Society of London. Series A, Mathematical and Physical Sciences 255 (1281): 153–180.
Treneer, Anne (1963). The Mercurial Chemist, A Life of Sir Humphry Davy. London: Methuen.
Hartley, Harold (1966). Humphry Davy. London: Nelson.
Fullmer, June Z. (1969). Sir Humphry Davy's Published Works. Cambridge, MA: Harvard University Press.
Knight, David (1992). Humphry Davy: Science and Power. Cambridge, UK: Cambridge University Press.
Lamont-Brown, Raymond (2004). Humphry Davy, Life Beyond the Lamp. Sutton Publishing.