(b. Penzance, England, 24 May 1790; d. Ambleside, England, 24 January 1868)
physiology, chemistry, natural history.
John Davy, youngest child and second son of Robert and Grace Millett Davy, undertook with honor and distinction the medical career originally intended for his brilliant older (by twelve years) brother, Humphry. Left fatherless at the age of four, Davy attended the schools of Penzance until 1808, when he went to London to assist his brother in the laboratory of the Royal Institution. He received no formal instruction there but was encouraged and guided so that he afterward wrote: “… in the Laboratory I acquired the habit of research with the love of labour to which whatever little success I may afterwards have attained, I mainly attribute.”
During his years at the University of Edinburgh, 1810–1814, Davy successfully defended his brother’s recently proposed views on the elemental nature of chlorine against the attacks by John Murray of that university. Out of this work he published the analyses and properties of the metallic chlorides, and first prepared, named, and characterized phosgene gas.
Davy received the M.D. in 1814, submitting a dissertation on the blood, and was soon after commissioned in the army as hospital assistant. Shortly before the battle of Waterloo he was assigned to the hospital at Brussels, and his experience there determined him on a career in the army medical service, in which he spent his entire professional life, eventually attaining the rank of inspector general of hospitals. He served many years abroad, in Ceylon, the Mediterranean islands, and the West Indies. Wherever he was stationed, Davy was a constant observer of the life habits and cultural practices of the native population, which he recorded with sympathy and detachment. He also dosed their bodies, took their temperatures, dissected their domestic and wild animals, and analyzed their minerals.
A diligent researcher and indefatigable writer, Davy derived his major scientific works from his medical service. Researches Physiological and Anatomical appeared in 1839, Diseases of the Army in 1862, and Physiological Researches in 1863. A voluminous output of papers on a broad miscellany of small topics reflects the range of opportunities that his travels presented to his ever alert but rather superficial curiosity.
Davy made a few original observations of significance, especially on the structure of the heart and circulatory system of the amphibians. His most sustained interest was in animal heat, and some of his observations on temperatures within the pulmonary circulation were widely cited at the time. He made thousands of temperature readings of men and beasts in all stages of health and sickness throughout the world; glowworms and elephants, clams and leopards, sharks, dogs, and chickens all felt his thermometer, but he seems not to have established any significant pattern or correlation.
Davy’s observations, although more opportune than creative, are not without insight; and his experiments show ingenuity. However, he did not often distinguish between the significant and the merely curious. He avoided speculations, preferring the role of discoverer; and even the most obvious generalizations were put forward with brevity and caution.
Davy was a persistent and oversensitive defender of his brother’s reputation. He wrote a two-volume biography in 1836 and edited the Collected Works of Sir Humphry Davy in 1839–1840 and a collection of letters and fragmentary works in 1858. He created a trivial quarrel with the gentle Faraday in the 1830’s, and as late as the 1860’s he was still defending Humphry’s conduct as president of the Royal Society against renewed attacks by Charles Babbage.
Although Davy’s scientific work is not of first rank, the wealth of original documentation provides a splendid opportunity for a significant study of a man whose professional career and attitudes are not unrepresentative of his times.
I. Original Works. John Davy’s books, all published in London, are readily classed into four categories:
Professional works are Researches Physiological and Anatomical, 2 vols. (1839); Lectures on the Study of Chemistry and Discourses on Agriculture (1849); On Some of the More Important Diseases of the Army, With Contributions to Pathology (1862); and Physiological Researches (1863).
Travel books are An Account of the Interior of Ceylon (1821); Notes and Observations on the Ionian Islands and Malta: With Some Remarks on Constantinople, Turkey, and on the System of Quarantine as at Present Conducted, 2 vols.(1842); and The West Indies Before and Since Slave Emancipation (1854).
Biographical works are Memoirs of the Life of Sir Humphry Davy, Bart., 2 vols. (1836); Collected Works of Sir Humphry Davy, Bart., which he edited, 9 vols. (1839–1840); and Fragmentary Remains, Literary and Scientific, of Sir Humphry Davy (1858).
His piscatory colloquies are The Angler and His Friend (1855); and The Angler in the Lake District (1857).
The Royal Society Catalogue of Scientific Papers lists 168 papers by Davy. Several dozen personal notebooks kept by John Davy are in the archives of the Royal Institution in London; six more are in the possession of the Royal Geological Society of Cornwall, and three are in the Morrab Gardens Library, both in Penzance. The library of Keele University, Staffordshire, owns the six notebooks used in the preparation of the Memoirs of his brother, along with a few miscellaneous papers including an incomplete autobiography.
II. Secondary Literature. No significant study of John Davy has been attempted. Brief accounts are found in the Dictionary of National Biography; Proceedings of the Royal Society, 16 (1868), lxxix-lxxxi; Proceedings of the Royal Society of Edinburgh (1869), 288–291; and Medical Times and Gazette (1868), 1, 160–161, and (1871), 2 , 390–391.
Davy, John , English song composer and violinist; b. Upton-Helions, near Exeter, Dec. 23, 1763; d. London, Feb. 22, 1824. He studied at Exeter, and then settled in
London, where he played the violin at Covent Garden. He wrote the music to a number of plays:A Pennyworth of Wit (London, April 18, 1796), Alfred the Great, a “grand historical ballet” (London, June 4, 1798), etc. “The Bay of Biscay, O!,” one of the songs from his incidental music to a play, Spanish Dollars, was extremely popular. He also composed an opéra, The Caffres, or Buried Alive (Covent Garden, London, June 2, 1802).
—Nicolas Slonimsky/Laura Kuhn/Dennis McIntire
John Davys: see Davis, John.