(b. Rotherham, England, 1751 [baptized 4 September]; d. London, England, 9 November 1828)
Pearson was one of the first chemists in Britain to accept the “antiphlogistic” theories of Lavoisier. He is best known for his role in introducing into Britain the nomenclature devised by Lavoisier and other leading French chemists. He studied medicine at Edinburgh University from 1770 to 1774 and received the M.D. in 1773; he also studied chemistry under Joseph Black. After a brief period at St. Thomas’s Hospital in London, Pearson spent about two years in Europe before establishing a medical practice in Doncaster, where he stayed for about six years. He eventually moved to London. In 1787 he became chief physician at St. George’s Hospital. He was admitted to the Royal Society in 1791 and for many years served on the council.
On hearing of Edward Jenner’s successful inoculation against smallpox, in which he used matter from the pustule of a cowpox patient, Pearson became interested in the subject. He published a number of articles and pamphlets and eventually set up an institution to provide vaccinations. His program, however, delayed, rather than hastened, the general adoption of Jenner’s method, for Pearson used a defective vaccine which frequently produced severe eruptions resembling smallpox. Ill feeling thus developed between Jenner and Pearson. Pearson tended to belittle Jenner’s achievements and opposed his successful claim for remuneration from the government.
A glimpse of Pearson as a lecturer was afforded by the American chemist Benjamin Silliman, who, when planning his visit to Europe in 1805–1806, had been given a letter of introduction to Pearson as “the greatest chemist in England.” Silliman said Pearson lectured on chemistry, materia medica, and therapeutics for two and a quarter hours without a break “There was no interval for breathing or for a gentle transition to a new subject. This mental repletion was not favorable to intellectual digestion” (see G. P. Fisher, Life of Benjamin Silliman, I [New York, 1866], 144–145).
Nevertheless Pearson seems to have been a competent chemist. He investigated the composition of “James’s powder,” a popular febrifuge which made a fortune for Robert James. He found that it was a mixture of bone ash and antimony oxide. In 1792 he extended the work of Smithson Tennant, who had shown that carbon was obtained when powdered marble was heated with phosphorus (S. Tennant, “On the Decomposition of Fixed Air,” in Philosophical Transactions of the Royal Society, 81 , 182–184). Pearson showed that sodium carbonate could be similarly decomposed, and he discovered calcium phosphide by heating phosphorus with quicklime. He noted the reaction of calcium phosphide with water and the spontaneous combustion of “phosphoric air” (phosphine). With J. Stodart he investigated the composition of Indian (“wootz”) steel (see R. A. Hadfield, Faraday and His Metallurgical Researches [London, 1931], pp. 36–37 and passim) and made a useful contribution to the history of metallurgy by analyzing some ancient weapons and utensils.
In 1789 the Dutch chemists A. Paete van Trosstwijk and J. R. Deiman succeeded in decomposing water by frictional electricity, although they were unable to show conclusively that hydrogen and oxygen were formed. They were assisted by J. Cuthbertson, who constructed the apparatus; Cuthbertson also collasborated with Pearson in a series of experiments over two years in the 1790’s in which a more convincing demonstration of the formation of the two constituents of water was effected. The amount of the gases actually obtained was, however, very small; and an entirely successful decomposition of water by electricity was not possible until the invention of the voltaic cell.
Pearson also published a number of papers of mainly medical content. He investigated a number of body tissues and fluids and showed, for example, that the blackening of lung tissue is caused by the absorption of carbon from the atmosphere. These researches were continued in an unpublished Bakerian lecture.
A feature of Lavoisier’s Méthode de nomenclature chimique (Paris, 1787) had been a large folding sheet which presented, in columns, the names of all known substances, classified according to the tenets of the new chemistry. Lavoisier gave the proposed new names in adjoining columns. It was this sheet that Pearson translated. He included both English and Latin equivalents, an explanatory text, and many additions. Pearson also adopted the term “nitrogen,” which was first coined by Chaptal as nitrogène. Pearson considered the original French azote unsuitable because it was based on a purely negative characteristic.
I. Original Works. Pearson’s M.D. dissertation was Disputatio physica inauguralis de putridine animalibus post mortem quam superveniente (Edinburgh, 1773). His investigation of the waters from the springs in Buxton, conducted while he was living in Doncaster, is embodied in Observations and Experiments for Investigating the Chymical History of the Tepid Springs of Buxton…, 2 vols. (London, 1784) and in a short pamphlet, Directions for Impregnating the Buxton Water, With Its Own and Other Gases, and for Composing Artificial Buxton Water (London, 1785). His most important pamphlets on vaccination are An Inquiry Concerning the History of the Cow Pox Principally With a View to Supersede and Extinguish the Small Pox (London, 1789), repr. in E. M. Crookshank, ed., History and Pathology of Vaccination, II (London, 1889), 34–91; and An Examination of the Report of the Committee of the House of Commons on the Claims of Remuneration for the Vaccine Pock Inoculation: Containing a Statement of the Principal Historical Facts of the Vaccina (London, 1802). He also published Heads and Notes of a Course of Chemical Lectures (London, 1806).
Pearson’s work on nomenclature is A Translation of the Table of Chemical Nomenclature, Proposed by De Guyton, Formerly de Morveau, Lavoisier, Berthollet & de Fourcroy; With Additions & Alterations, Prefixed by an Explanation of the Terms, and Some Observations on the New System of Chemistry (London, 1794). A 2nd, enl. ed. was published in 1799, in which Pearson added tables of chemical affinity; the new symbols of J. H. Hassenfratz and P. A. Adet, which had appeared in the Methode de nomenclature chymique; and symbols used by T. Bergman and C. J. Geoffroy. He also included objections that had been made to the new nomenclature by various chemists.
An incomplete list of Pearson’s papers is in the Royal Society Catalogue of Scientific Papers, IV, 795. His writings include “Experiments & Observations to Investigate the Composition of James’s Powder,” in Philosophical Transactions of the Royal Society, 81 (1791), 317–367; “Experiments Made With the View of Decompounding Fixed Air, or Carbonic Acid,” ibid., 82 (1792), 289–308; “Experiments to Investigate the Nature of a Kind of Steel, Manufactured at Bombay and There Called Wootz; With Remarks on the Properties and Composition of the Different States of Iron,” ibid., 85 (1795), 322–346’ “Observations on Some Ancient Metallic Arms & Utensils; With Experiments to Determine Their Composition,” ibid., 86 (1796), 395–451; “Experiments & Observations Made With a View of Ascertaining the Nature of the Gas Produced by Passing Electric Discharges Through Water,” ibid., 87 (1797), 142–158, full paper in Nicholson’s Journal of Natural Philosophy, Chemistry & the Arts, 1 (1797), 241–248, 299–305, 349–355; “On the Colouring Matter of the Black Bronchial Glands, and of the Black Spots of the Lungs,” in Philosophical Transactions of the Royal Society, 103 (1813), 159–170; and “Researches to Discover the Faculties of Pulmonary Absorption, With Respect to Charcoal,” MS in the Royal Society Archives, A.P. 13 (1827–1829), no. 21, read 20 Dec. 1827.
II. Secondary Literature. No informative biography of Pearson exists. A short account, with a list of his publications, is in Gentleman’s Magazine, 99 , pt. 1 (1829), 129–131. A partial account of Pearson’s involvement with Jenner is given by D. Fisk, Dr. Jenner of Berkeley (London, 1959), 148 and passim.
E. L. Scott