1911 Encyclopædia Britannica/Davy, Sir Humphry
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Davy, Sir Humphry
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DAVY, SIR HUMPHRY, Bart. (1778-1829), English chemist, was born on the 17th of December 1778 at or near Penzance in Cornwall. During his school days at the grammar schools of Penzance and Truro he showed few signs of a taste for scientific pursuits or indeed of any special zeal for knowledge or of ability beyond a certain skill in making verse translations from the classics and in story-telling. But when in 1794 his father, Robert Davy, died, leaving a widow and five children in embarrassed circumstances, he awoke to his responsibilities as the eldest son, and becoming apprentice to a surgeon-apothecary at Penzance set to work on a systematic and remarkably wide course of self-instruction which he mapped out for himself in preparation for a career in medicine. Beginning with metaphysics and ethics and passing on to mathematics, he turned to chemistry at the end of 1797, and within a few months of reading Nicholson's and Lavoisier's treatises on that science had produced a new theory of light and heat. About the same time he made the acquaintance of two men of scientific attainments — Gregory Watt (1777-1804), a son of James Watt, and Davies Giddy, afterwards Gilbert (1767-1839), who was president of the Royal Society from 1827 to 1831. By the latter he was recommended to Dr Thomas Beddoes, who was in 1798 establishing his Medical Pneumatic Institution at Bristol for investigating the medicinal properties of various gases. Here Davy, released from his indentures, was installed as superintendent towards the end of 1798. Early next year two papers from his pen were published in Beddoes' West Country Contributions — one “On Heat, Light and the Combinations of Light, with a new Theory of Respiration and Observations on the Chemistry of Life,” and the other “On the Generation of Phosoxygen (Oxygen gas) and the Causes of the Colours of Organic Beings.” These contain an account of the well-known experiment in which he sought to establish the immateriality of heat by showing its generation through the friction of two pieces of ice in an exhausted vessel, and further attempt to prove that light is “matter of a peculiar kind,” and that oxygen gas, being a compound of this matter with a simple substance, would more properly be termed phosoxygen. Founded on faulty experiments and reasoning, the views he expressed were either ignored or ridiculed; and it was long before he bitterly regretted the temerity with which he had published his hasty generalizations.
One of his first discoveries at the Pneumatic Institution on the 9th of April 1799 was that pure nitrous oxide (laughing gas) is perfectly respirable, and he narrates that on the next day he became “absolutely intoxicated” through breathing sixteen quarts of it for “near seven minutes.” This discovery brought both him and the Pneumatic Institution into prominence. The gas itself was inhaled by Southey and Coleridge among other distinguished people, and promised to become fashionable, while further research yielded Davy material for his Researches, Chemical and Philosophical, chiefly concerning Nitrous Oxide, published in 1800, which secured his reputation as a chemist. Soon afterwards, Count Rumford, requiring a lecturer on chemistry for the recently established Royal Institution in London, opened negotiations with him, and on the 16th of February 1801 he was engaged as assistant lecturer in chemistry and director of the laboratory. Ten weeks later, having “given satisfactory proofs of his talents” in a course of lectures on galvanism, he was appointed lecturer, and his promotion to be professor followed on the 31st of May 1802. One of the first tasks imposed on him by the managers was the delivery of a course of lectures on the chemical principles of tanning, and he was given leave of absence for July, August and September 1801 in order to acquaint himself practically with the subject. The main facts he discovered from his experiments in this connexion were described before the Royal Society in 1803. In 1802 the board of agriculture requested him to direct his attention to agricultural subjects; and in 1803, with the acquiescence of the Royal Institution, he gave his first course of lectures on agricultural chemistry and continued them for ten successive years, ultimately publishing their substance as Elements of Agricultural Chemistry in 1813. But his chief interest at the Royal Institution was with electro-chemistry. Galvanic phenomena had already engaged his attention before he left Bristol, but in London he had at his disposal a large battery which gave him much greater opportunities. His first communication to the Royal Society, read in June 1801, related to galvanic combinations formed with single metallic plates and fluids, and showed that an electric cell might be constructed with a single metal and two fluids, provided one of the fluids was capable of oxidizing one surface of the metal; previous piles had consisted of two different metals, or of one plate of metal and the other of charcoal, with an interposed fluid. Five years later he delivered before the Royal Society his first Bakerian lecture, “On some Chemical Agencies of Electricity,” which J. J. Berzelius described as one of the most remarkable memoirs in the history of chemical theory. He summed up his results in the general statement that “hydrogen, the alkaline substances, the metals and certain metallic oxides are attracted by negatively electrified metallic surfaces, and repelled by positively electrified metallic surfaces; and contrariwise, that oxygen and acid substances are attracted by positively electrified metallic surfaces and repelled by negatively electrified metallic surfaces; and these attractive and repulsive forces are sufficiently energetic to destroy or suspend the usual operation of elective affinity.” He also sketched a theory of chemical affinity on the facts he had discovered, and concluded by suggesting that the electric decomposition of neutral salts might in some cases admit of economical applications and lead to the isolation of the true elements of bodies. A year after this paper, which gained him from the French Institute the medal offered by Napoleon for the best experiment made each year on galvanism, he described in his second Bakerian lecture the electrolytic preparation of potassium and sodium, effected in October 1807 by the aid of his battery. According to his cousin, Edmund Davy, then his laboratory assistant, he was so delighted with this achievement that he danced about the room in ecstasy. Four days after reading his lecture his health broke down, and severe illness kept him from his professional duties until March 1808. As soon as he was able to work again he attempted to obtain the metals of the alkaline earths by the same methods as he had used for those of the fixed alkalis, but they eluded his efforts and he only succeeded in preparing them as amalgams with mercury, by a process due to Berzelius. His attempts to decompose “alumine, silica, zircone and glucine” were still less fortunate. At the end of 1808 he read his third Bakerian lecture, one of the longest of his papers but not one of the best. In it he disproved the idea advanced by Gay Lussac that potassium was a compound of hydrogen, not an element; but on the other hand he cast doubts on the elementary character of phosphorus, sulphur and carbon, though on this point he afterwards corrected himself. He also described the preparation of boron, for which at first he proposed the name boracium, on the impression that it was a metal. About this time a voluntary subscription among the members of the Royal Institution put him in possession of a new galvanic battery of 2000 double plates, with a surface equal to 128,000 sq. in., to replace the old one, which had become unserviceable. His fourth Bakerian lecture, in November 1809, gave further proofs of the elementary nature of potassium, and described the properties of telluretted hydrogen. Next year, in a paper read in July and in his fifth Bakerian lecture in November, he argued that oxymuriatic acid, contrary to his previous belief, was a simple body, and proposed for it the name “chlorine.”
Davy's reputation was now at its zenith. As a lecturer he could command an audience of little less than 1000 in the theatre of the Royal Institution, and his fame had spread far outside London. In 1810, at the invitation of the Dublin Society, he gave a course of lectures on electro-chemical science, and in the following year he again lectured in Dublin, on chemistry and geology, receiving large fees at both visits. During his second visit Trinity College conferred upon him the honorary degree of LL.D., the only university distinction he ever received. On the 8th of April 1812 he was knighted by the prince regent; on the 9th he gave his farewell lecture as professor of chemistry at the Royal Institution; and on the 11th he was married to Mrs Apreece, daughter and heiress of Charles Kerr of Kelso, and a distant connexion of Sir Walter Scott. A few months after his marriage he published the first and only volume of his Elements of Chemical Philosophy, with a dedication to his wife, and was also re-elected professor of chemistry at the Royal Institution, though he would not pledge himself to deliver lectures, explaining that he wished to be free from the routine of lecturing in order to have more time for original work. Towards the end of the year he began to investigate chloride of nitrogen, which had just been discovered by P. L. Dulong, but was obliged to suspend his inquiries during the winter on account of injury to his eye caused by an explosion of that substance. In the spring of 1813 he was engaged on the chemistry of fluorine, and though he failed to isolate the element, he reached accurate conclusions regarding its nature and properties. In October he started with his wife for a continental tour, and with them, as “assistant in experiments and writing,” went Michael Faraday, who in the previous March had been engaged as assistant in the Royal Institution laboratory. Having obtained permission from the French emperor to travel in France, he went first to Paris, where during his two months' stay every honour was accorded him, including election as a corresponding member of the first class of the Institute. He does not, however, seem to have reciprocated the courtesy of his French hosts, but gave offence by the brusqueness of his manner, though his supercilious bearing, according to his biographer, Dr Paris, was to be ascribed less to any conscious superiority than to an “ungraceful timidity which he could never conquer.” Nor was his action in regard to iodine calculated to conciliate. That substance, recently discovered in Paris, was attracting the attention of French chemists when he stepped in and, after a short examination with his portable chemical laboratory, detected its resemblance to chlorine and pronounced it an “undecompounded body.” Towards the end of December he left for Italy. At Genoa he investigated the electricity of the torpedo-fish, and at Florence, by the aid of the great burning-glass in the Accademia del Cimento, he effected the combustion of the diamond in oxygen and decided that, beyond containing a little hydrogen, it consisted of pure carbon. Then he went to Rome and Naples and visited Vesuvius and Pompeii, called on Volta at Milan, spent the summer in Geneva, and returning to Rome occupied the winter with an inquiry into the composition of ancient colours.
A few months after his return, through Germany, to London in 1815, he was induced to take up the question of constructing a miner's safety lamp. Experiments with samples of fire-damp sent from Newcastle soon taught him that “explosive mixtures of mine-damp will not pass through small apertures or tubes”; and in a paper read before the Royal Society on the 9th of November he showed that metallic tubes, being better conductors of heat, were superior to glass ones, and explained that the heat lost by contact with a large cooling surface brought the temperature of the first portions of gas exploded below that required for the firing of the other portions. Two further papers read in January 1816 explained the employment of wire gauze instead of narrow tubes, and later in the year the safety lamps were brought into use in the mines. A large collection of the different models made by Davy in the course of his inquiries is in the possession of the Royal Institution. He took out no patent for his invention, and in recognition of his disinterestedness the Newcastle coal-owners in September 1817 presented him with a dinner-service of silver plate.
In 1818, when he was created a baronet, he was commissioned by the British government to examine the papyri of Herculaneum in the Neapolitan museum, and he did not arrive back in England till June 1820. In November of that year the Royal Society, of which he had become a fellow in 1803, and acted as secretary from 1807 to 1812, chose him as their president, but his personal qualities were not such as to make him very successful in that office, especially in comparison with the tact and firmness of his predecessor, Sir Joseph Banks. In 1821 he was busy with electrical experiments and in 1822 with investigations of the fluids contained in the cavities of crystals in rocks. In 1823, when Faraday liquefied chlorine, he read a paper which suggested the application of liquids formed by the condensation of gases as mechanical agents. In the same year the admiralty consulted the Royal Society as to a means of preserving the copper sheathing of ships from corrosion and keeping it smooth, and he suggested that the copper would be preserved if it were rendered negatively electrical, as would be done by fixing “protectors” of zinc to the sheeting. This method was tried on several ships, but it was found that the bottoms became extremely foul from accumulations of seaweed and shellfish. For this reason the admiralty decided against the plan, much to the inventor's annoyance, especially as orders to remove the protectors already fitted were issued in June 1825, immediately after he had announced to the Royal Society the full success of his remedy.
In 1826 Davy's health, which showed signs of failure in 1823, had so declined that he could with difficulty indulge in his favourite sports of fishing and shooting, and early in 1827, after a slight attack of paralysis, he was ordered abroad. After a short stay at Ravenna he removed to Salzburg, whence, his illness continuing, he sent in his resignation as president of the Royal Society. In the autumn he returned to England and spent his time in writing his Salmonia or Days of Flyfishing, an imitation of The Compleat Angler. In the spring of 1828 he again left England for Illyria, and in the winter fixed his residence at Rome, whence he sent to the Royal Society his “Remarks on the Electricity of the Torpedo,” written at Trieste in October. This, with the exception of a posthumous work, Consolations in Travel, or the Last Days of a Philosopher (1830), was the final production of his pen. On the 20th of February 1829 he suffered a second attack of paralysis which rendered his right side quite powerless, but under the care of his brother, Dr John Davy (1791-1868), he rallied sufficiently to be removed to Geneva, where he died on the 29th of May.
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 connexion 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.
See Dr J. A. Paris, The Life of Sir Humphry Davy (1831), vol. ii of which on pp. 450-456 gives a list of his publications. Dr John Davy, Memoirs of Sir Humphry Davy (1836); Collected Works (with shorter memoir, 1839); Fragmentary Remains, Literary and Scientific (1858). T. E. Thorpe, Humphry Davy, Poet and Philosopher (1896).
- Edmund Davy (1785-1857) became professor of chemistry at Cork Institution in 1813, and at the Royal Dublin Society in 1826. His son, Edmund William Davy (born in 1826), was appointed professor of medicine in the Royal College, Dublin, in 1870.
- Davy's will directed that this service, after Lady Davy's death, should pass to his brother, Dr John Davy, on whose decease, if he had no heirs who could make use of it, it was to be melted and sold, the proceeds going to the Royal Society “to found a medal to be given annually for the most important discovery in chemistry anywhere made in Europe or Anglo-America.” The silver produced £736, and the interest on that sum is expended on the Davy medal, which was awarded for the first time in 1877, to Bunsen and Kirchhoff for their discovery of spectrum analysis.