Sir humphry davy

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2. Sir Humphry Davy


Sir Humphry Davy, Bt

Born 17 December 1778
Penzance, Cornwall, England
Died 29 May 1829 (aged 50)
Geneva, Switzerland
Nationality British
Fields Chemistry
Institutions Royal Society, Royal Institution
Known for Electrolysis, aluminium, sodium,potassium, calcium, magnesium,barium, boron, Davy
lamp

3. Influenced Michael Faraday, William Thomson
Notable
awards
Copley Medal (1805)
Rumford Medal (1816)
Royal Medal (1827)
Sir Humphry Davy, 1st Baronet (17 December 1778 – 29 May 1829) was a Cornish chemist and
inventor.
[1]
He is best remembered today for his discoveries of several alkali and alkaline earth metals, as
well as contributions to the discoveries of the elemental nature of chlorine and iodine. 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." He was a 1st Baronet, President of the Royal Society
(PRS), Member of the Royal Irish Academy (MRIA), and Fellow of the Geological Society (FGS).
Early scientific interests
Davies Giddy met Davy in Penzance carelessly swinging on the half-gate of Dr Borlase's house, and
interested by his talk invited him to his house at Tredrea and offered him the use of his library. This led to
an introduction to Dr Edwards, who lived at Hayle Copper House. Edwards was a lecturer in chemistry in
the school of St. Bartholomew's Hospital. He permitted Davy to use his laboratory and possibly directed
his attention to the floodgates of the port of Hayle, which were rapidly decaying as a result of the contact
between copper and iron under the influence of seawater. Galvanic corrosion was not understood at that
time, but the phenomenon prepared Davy's mind for subsequent experiments on ship's copper sheathing.
Gregory Watt, son of James Watt, visited Penzance for his health's sake, and while lodging at the Davy's
house became a friend and gave him instructions in chemistry. Davy was acquainted with
the Wedgwood family, who spent a winter at PenzanceThomas Beddoes and John Hailstone were
engaged in a geological controversy on the rival merits of the Plutonian and Neptunist hypotheses. They
travelled together to examine the Cornish coast accompanied by Davies Gilbert and made Davy's
acquaintance. Beddoes, who had established at Bristol a 'Pneumatic Institution,' needed an assistant to
superintend the laboratory. Gilbert recommended Davy, and in 1798 Gregory Watt showed Beddoes
the Young man's Researches on Heat and Light, which were subsequently published by him in the first
volume of West-Country Contributions. After prolonged negotiations, mainly by Gilbert, Mrs Davy and
Borlase consented to Davy's departure, but Tonkin wished him to remain in his native town as a surgeon,
and altered his will when he found that Davy insisted on going to Dr Beddoes.
In 1802, Humphry Davy had what was then the most powerful electrical battery in the world at the Royal
Institution. With it, Davy created the first incandescent light by passing a current through a thin strip of
platinum, chosen because the metal had an extremely high melting point. It was neither sufficiently bright
nor long lasting enough to be of practical use, but demonstrated the principle. By 1806 he was able to
demonstrate a much more powerful form of electric lighting to the Royal Society in London. It was an
early form of arc light which produced its illumination from an electric arc created between two charcoal
rods.

4. Pneumatic Institution

James Watt in 1792 byCarl Frederik von Breda
On 2 October 1798, Davy joined the Pneumatic Institution at Bristol. It had been established to investigate
the medical powers of factitious airs and gases, and Davy was to superintend the various experiments.
The arrangement agreed between Dr Beddoes and Davy was liberal and enabled Davy to give up all
claims on his paternal property in favour of his mother. He did not intend to abandon the medical
profession and was determined to study and graduate at Edinburgh but he soon began to fill parts of the
institution with voltaic batteries. While living in Bristol, Davy met the Earl of Durham, who was a resident
in the institution for his health and became close friends with Gregory Watt, James Watt, Samuel Taylor
Coleridge and Robert Southey, all of whom became regular users of nitrous oxide (laughing gas), to
which Davy became addicted. The gas was first synthesized in 1772 by the natural philosopher and
chemist Joseph Priestley, who called it phlogisticated nitrous air (see phlogiston).
[8]
Priestley described his
discovery in the book Experiments and Observations on Different Kinds of Air (1775), in which he
described how to produce the preparation of "nitrous air diminished", by heating iron filings dampened
with nitric acid James Watt built a portable gas chamber to facilitate Davy's experiments with the
inhalation of nitrous oxide. At one point the gas was combined with wine to judge its efficacy as a cure
for hangover (his laboratory notebook indicated success). The gas was popular among Davy's friends and
acquaintances, and he noted that it might be useful for performing surgical operations Anesthetics were
not regularly used in medicine or dentistry until decades after Davy's death. Davy threw himself
energetically into the work of the laboratory and formed a long romantic friendship with Mrs Anna
Beddoes, who acted as his guide on walks and other fine sights of the locality. In December 1799 Davy
visited London for the first time and extended his circle of friends.In the gas experiments Davy ran
considerable risks. His respiration of nitric oxide which may have combined with air in the mouth to
form nitric acid (HNO3), severely injured the mucous membrane, and in Davy's attempt to inhale four
quarts of 'pure hydrocarbonate' gas in an experiment with carbon monoxide he 'seemed sinking into
annihilation.' On being removed into the open air, Davy faintly articulated, 'I do not think I shall die, but
some hours elapsed before the painful symptoms ceased. Davy was able to take his own pulse as he
staggered out of the laboratory and into the garden, and he described it in his notes as 'threadlike and
beating with excessive quickness'.
In this year the first volume of the West-Country Collections was issued. Half 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, wrote to Davies Gilbert, ‘I am now as much
convinced of the non-existence of caloric as I am of the existence of light.' In another letter to 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 said 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 he had ever published these immature hypotheses, which he

5. subsequently designated ‘the dreams of misemployed genius which the light of experiment and
observation has never conducted to truth
Davy's later time at the institution was spent partially in experimentation. In 1800, Davy informed 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.’
Roy al Institution
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.

1802 satirical cartoon by James Gillray showing a Royal Institutionlecture on pneumatics, with Davy
holding the bellows and Count Rumford looking on at extreme right. Dr Garnett is the lecturer, holding the
victim's nose.
In February 1801 Davy was interviewed by the committee of the Royal Institution, comprising Joseph
Banks,Benjamin Thompson (who had been appointed Count Rumford) and Henry Cavendish. Davy wrote
to Davies Gilbert on 8 March 1801 about the offers made by Banks and Thompson, a possible move to
London and the promise of funding for his work in galvanism. He also mentioned that he might not be
collaborating further with Beddoes on therapeutic gases. The next day Davy left Bristol to take up his new
post at the Royal Institution. it having been resolved '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.On 25 April
1801, Davy gave his first lecture on the relatively new subject of 'Galvanism'. He and his friend Coleridge
had had many conversations about the nature of human knowledge and progress, and Davy's lectures
gave his audience a vision of human civilisation brought forward by scientific discovery. "It [science] has
bestowed on him powers which may almost be called creative; which have enabled him to modify and
change the beings surrounding him, and by his experiments to interrogate nature with power, not simply
as a scholar, passive and seeking only to understand her operations, but rather as a master, active with
his own instruments. The first lecture garnered rave reviews, and by the June lecture Davy wrote to John
King that his last lecture had attendance of nearly 500 people. "There was Respiration, Nitrous Oxide,
and unbounded Applause. Amen!
Davy's lectures also included spectacular and sometimes dangerous chemical demonstrations for his
audience, a generous helping of references to divine creation, and genuine scientific information. Not only

6. a popular lecturer, the young and handsome Davy acquired a huge female following around London, and
nearly half of the attendees pictured in Gillray's cartoon are female. When Davy's lecture series on
Galvanism ended, he progressed to a new series on Agricultural Chemistry, and his popularity continued
to skyrocket. By June 1802, after just over a year at the Institution and at the age of 23, Davy was
nominated to full lecturer at the Royal Institution of Great Britain. Garnett quietly resigned, citing health
reasons. In November 1804 Davy became a Fellow of the Royal Society, over which he would later
preside. He was one of the founding members of the Geological Society in 1807and was elected a foreign
member of the Royal Swedish Academy of Sciences in 1810.
Discovery of new elements

Sodiummetal, about 10 g, under oil

A voltaic pile

Magnesium metal crystals
Davy was a pioneer in the field of electrolysis using the voltaic pile to split common compounds and thus
prepare many new elements. He went on to electrolyse molten salts and discovered several new metals,

7. including sodium and potassium, highly reactive elements known as the alkali metals. Davy discovered
potassium in 1807, deriving it from caustic potash (KOH). Before the 19th century, no distinction had
been made between potassium and sodium. Potassium was the first metal that was isolated by
electrolysis. Davy isolated sodium in the same year by passing an electric current through molten sodium
hydroxide. Davy discovered 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 was
first to isolate magnesium, boron, and barium.
Discovery of chlorine
Chlorine was discovered in 1774 by Swedish chemist Carl Wilhelm Scheele, who called
it "dephlogisticated marine acid" (seephlogiston theory) and mistakenly thought it contained oxygen. Davy
showed that the acid of Scheel's substance, called at the time oxymuriatic acid, contained no oxygen.
This discovery overturned Lavoisier's definition of acids as compounds of oxygen. In 1810, chlorine was
given its current name by Humphry Davy, who insisted that chlorine was in fact an element.
Popular public figure
Davy revelled in his public status, as his lectures gathered many spectators. He became well known in
1799 due to his experiments with the physiological action of some gases, including laughing gas (nitrous
oxide), with enthusiastic experimental subjects including his poet friends Robert Southey and Samuel
Taylor Coleridge. Davy later damaged his eyesight in a laboratory accident with nitrogen
trichloride.
[18]
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.
European travels

Sir Humphry Davy, 1830 engraving based on the painting by Sir Thomas Lawrence (1769–1830)

A diamond crystal in its matrix
In 1812, Davy was knighted, gave a farewell lecture to the Royal Institution, and married a wealthy widow,
Jane Apreece. (While Davy was generally acknowledged as being faithful to his wife, their relationship
was stormy, and in later years he travelled to continental Europe alone.) In October 1813, he and his wife,
accompanied by Michael Faraday as his scientific assistant (and valet), travelled to France to collect a
medal that Napoleon Bonaparte had awarded Davy for his electro-chemical work. While in Paris, Davy

8. 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 1813, travelling
south to Italy.
[21]
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 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 Istanbul were abandoned after
Napoleon's escape from Elba, they returned to England.
Davy lamp

The Davy lamp

A statue of Davy stands in Penzance, Cornwall; he holds his safety lamp in his right hand.
Main article: 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 byfiredamp or methane often ignited by open flames of the lamps then
used by miners. In particular the Felling mine disaster in 1812 near Newcastlecaused 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

9. 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 used by
many other inventors in their later designs. George Stephenson's lamp was very popular in the north-east
coalfields, and used the same principle of preventing the flame reaching the general atmosphere, but by
different means. Unfortunately, although the new design of gauze lamp initially did seem to offer
protection, it gave much 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 his 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.
Last years and death

Michael Faraday, portrait by Thomas Phillipsc. 1841–1842
In January 1819, Davy was awarded a baronetcy. Although Sir Francis Bacon (also later made a peer
]
)
andSir Isaac Newton had already been knighted, this was, at the time, the first such honour ever
conferred on a man of science in Britain. A year later he became President of the Royal Society.
Davy's laboratory assistant, Michael Faraday, went on to enhance Davy's work and would become the
more famous and influential scientist. Davy is supposed to have even claimed Faraday as his greatest
discovery. Davy later accused Faraday of plagiarism, however, causing Faraday (the first Fullerian
Professor of Chemistry) to cease all research in electromagnetism until his mentor's death.
Of a sanguine, somewhat irritable temperament, Davy displayed characteristic enthusiasm and energy in
all his pursuits. As is shown by his verses and sometimes by his prose, his mind was highly imaginative;
the poet Coleridge declared that if he "had not been the first chemist, he would have been the first poet of
his age", and Southey said that "he had all the elements of a poet; he only wanted the art." In spite of his
ungainly exterior and peculiar manner, his happy gifts of exposition and illustration won him extraordinary
popularity as a lecturer, his experiments were ingenious and rapidly performed, and Coleridge went to
hear him "to increase his stock of metaphors." The dominating ambition of his life was to achieve fame,
but though that sometimes betrayed him into petty jealousy, it did not leave him insensible to the claims
on his knowledge of the "cause of humanity", to use a phrase often employed by him in connection with
his invention of the miners' lamp. Of the smaller observances of etiquette he was careless, and his
frankness of disposition sometimes exposed him to annoyances which he might have avoided by the
exercise of ordinary tact. According to one of Davy's biographers, June Z. Fullmer, he was a deist.

10. Davy's grave at Cimetière Plainpalais in Geneva
He spent the last months of his life writing Consolations in Travel, an immensely popular, somewhat
freeform compendium of poetry, thoughts on science and philosophy. Published posthumously, the work
became a staple of both scientific and family libraries for several decades afterward. Davy spent the
winter in Rome, hunting in the Campagna on his fiftieth birthday. But on 20 February 1829 he had another
stroke. After spending many months attempting to recuperate, Davy died in a hotel room in Geneva,
Switzerland, on 29 May 1829.He had wished to be buried where he died, but had also wanted the burial
delayed in case he was only comatose. He refused to allow a post-mortem for similar reasons. But the
laws of Geneva did not allow any delay and he was given a public funeral on the following Monday, in
the Plainpalais Cemetery, outside the city walls. Jane organised a memorial tablet for him, in Westminster
Abbey shortly afterwards, at a cost of £142.