Henry, William

(b. Manchester, England, 12 December 1774; d. Manchester, 2 September 1836)

chemistry.

The third son of Thomas Henry—probably the most talented and certainly the most successful of the three—William Henry went first to a private school run by a Unitarian minister and then to Manchester Academy. From the age of ten an injury from which he never fully recovered, inflicted by a falling beam, prohibited him from normal boyhood activities, and he early developed a taste for study. After leaving the academy (about 1790) he became secretarycompanion to Thomas Percival and began preliminary studies in medicine. He entered Edinburgh University in 1795 but left a year later to assist in his father’s practice and to superintend the family manufacturing business.

Henry became a member of the Manchester Literary and Philosophical Society in 1796 and began to carry out original research in chemistry. In 1805 he returned to Edinburg and received the M.D. in 1807, submitting a dissertation on uric acid; he later specialized in urinary diseases and contributed papers to medical journals on these and allied subjects. He was elected a fellow of the Royal Society in 1808 and received the Copley Medal for papers already submitted.

Henry’s first paper (1797) was a refutation of William Austin’s claim to have shown that carbon was not an element (1789). In 1800 he described an attempt to determine the nature of muriatic acid (hydrochloric acid); although he obtained hydrogen and oxymuriatic acid (chlorine) on sparking muriatic acid gas over mercury, he attributed the former to water, from which he believed it was impossible to free the gas by chemical means. In 1801 Henry tried the new technique of electrolysis (he was one of the first to experiment with this) but considered it seriously limited on finding that the current could not be transmitted through gases. In 1812, after the classic researches of Gay-Lussac and Thénard in France and of Davy in England had provided the evidence for the elementary nature of oxymuriatic acid and its combination with hydrogen in muriatic acid, Henry related further experiments which appeared to favor the new views. Yet it was several years before he finally committed himself to them.

This cautious attitude toward new ideas characterized Henry’s later years, although in his youth he had eagerly embraced the new chemistry of Lavoisier. At Manchester, in the winter of 1798–1799 he had given his first lecture demonstrations, firmly grounded in the new doctrines and nomenclature. His textbook, originally based on these lectures, was first published in 1801; it went to eleven editions, each larger than the previous one. Henry’s Elements was the most popular and successful chemistry text in English for more than thirty years.

Also in 1801 Henry read his first paper to the Manchester Literary and Philosophical Society—a rebuttal of Davy’s arguments against the materiality of heat; he was a lifelong calorist. In 1802 he read to the Royal Society the paper which established “Henry’s law,” and in 1805 there appeared the first of a series of works on the analysis of mixtures of gaseous hydrocarbons.

Stimulated by the recent trials of coal gas for lighting purposes, Henry set out to analyze various inflammable mixtures of gases obtained from coal and other materials of organic origin, with a view to determining their relative powers of illumination and to explain the differences in terms of their compositions. His investigations covered a period of more than twenty years, during which he gradually improved his analytic techniques. As well as representing a significant contribution to the progress of the gas industry, his work confirmed that of Dalton on the compositions of methane and ethylene; and their conviction that hydrogen and carbon combined only in definite proportions, to form a limited number of compounds, preceded the general acceptance of this view. In his final investigation Henry made use of the catalytic properties of platinum discovered in 1824 y Döbereiner.

The friendship of Henry with Dalton, for which he is now chiefly remembered, is best exemplified against the background of Henry’s law relating to the solubility of gases: “... under equal circumstances of temperature, water takes up, in all cases, the same volume of condensed gas as of gas under ordinary pressure...” (Philosophical Transactions of the Royal Socieiy, 93 [1803], 41). In 1801 Dalton had been absorbed by the problem of why an atmosphere consisting of gases of different densities did not separate into layers. His speculations gave rise to his theory of mixed gases (the embryo of the law of partial pressures), the best contemporary expression of which was given by Henry: “Every gas is a vacuumto every other gas” (Nicholson’s Journal of Natural Philosophy, Chemistry, and the Arts, 8 [1804], 298). Henry had at first been among the many critics of the theory; but a suggestion made to him by Dalton in the light of it had enabled him to account for certain discrepancies in his solubility experiments, and he came out strongly in its defense. Dalton’s own experiments on the solution of gases and the stimulus afforded by Henry’s work have been seen as crucial in the development of the atomic theory (see L. K. Nash, “The Origin of Dalton’s Chemical Atomic Theory,” in lsis, 47 [1956], 101–116; and E. L. Scott, “Dalton and William Henry,” in D. S. L. Cardwell, ed., John Dalton and the Progress of Science [Manchester–New York, 1968], pp. 220–239).

In 1809 Henry applied his analytical techniques to the composition of ammonia, confirming and refining the earlier work of Claude Berthollet, A. B. Berthollet, and Davy with respect to the proportions of hydrogen and nitrogen and showing that Davy was mistaken in thinking it contained oxygen. Later (1824) he succeeded in reconciling the results with Gay-Lussac’s law and confirmed the latter’s analysis of certain oxides of nitrogen.

Henry’s 1824 papers were the last of any importance in experimental chemistry. Some time after this he was forced to abandon manipulative experiments because of surgical operations performed on his hands. He turned to the study of contagious diseases, which he believed were spread by chemical substances. Other adherents of this theory had tried to destroy the “contagion” by chemical reactions, usually with noxious reagents such as chlorine; Henry believed, and satisfied himself by experiment, that the “contagion” was heat-labile and could be inactivated by moderate heat. The advent of Asiatic cholera in 1831 made this work topical, and he devised a cheap and simple apparatus for disinfection by heat of clothing and other items. His hope that the method would be widely used was not realized, and his work was forgotten for many years—until long after the germ theory of disease provided a different reason for disinfection by heat.

Henry suffered from chronic ill health besides the neuralgic pains resulting from his injury, which finally became so acute as to deprive him of sleep; he committed suicide in 1836. He was highly esteemed in his day, but much of his work is a confirmation of others’—valuable but not spectacular. He tended to be cautious and unspeculative. Lacking the boldness of his friend Dalton, his commitment to the atomic theory, the initial formulation of which he had assisted, was belated and reserved. Thus, he missed the opportunity, afforded by his unique relationship with Dalton and his superiority in experimental skill, to accelerate the acceptance of a theory that was to become the very foundation of modern chemistry.

Henry is sometimes confused with his son William Charles Henry, who studied medicine at Edinburgh and chemistry under Liebig in Germany. He published a few papers, but after the shock of his father’s death, he retired from medicine and science at the age of thirty-three and lived the life of a country gentleman in Herefordshire. He is generally known only for his biography of Dalton.

BIBLIOGRAPHY

I. Original Works. Henry’s books are An Epitome of Chemistry in Three Parts (London, 1801 [2 eds.], 1803; Edinburgh, 1806; London, 1808); and The Elements of Experimental Chemistry, 2 vols. (London, 1810 [styled 6th ed.], 1815, 1818, 1823, 1826, 1829). The last (11th) ed. contains biographical sketches of Davy and William Wollaston. An Estimate of the Philosophical Character of Dr. Priestley (York, 1832), with app., a penetrating study, was read to the British Association for the Advancement of Science at York in 1831—it also appears, without the app., in Report of the British Association for the Advancement of Science, for 1831 and 1832 (1833), 60–71.

His scientific papers, with a few exceptions, are listed in Royal Society Catalogue of Scientific Papers, III (London, 1869), 293–295. Those mentioned in the text are “Experiments on Carbonated Hydrogen Gas; With a View to Determine Whether Carbon Be a Simple or a Compound Substance,” in Philosophical Transactions of the Royal Society, 87 (1797), 401–415; “Account of a Series of Experiments Undertaken With the View of Decomposing the Muriatic Acid,” ibid., 90 (1800), 188–203; “A Review of Some Experiments, Which Have Been Supposed to Disprove the Materiality of Heat,” in Memoirs of the Manchester Literary and Philosophical Society, 5 (1802), 603–621; “Experiments on the Quantity of Gases Absorbed by Water at Different Temperatures and Under Different Pressures,” in Philosophical Transactions of the Royal Society,93 (1803), 29–42, 274–276; “Illustrations of Mr. Dalton’s Theory of the Constitution of” Mixed Gases,” in Nicholson’s Journal of Natural Philosophy, Chemistry, and the Arts,8 (1804), 297–301; “Experiments on the Gases Obtained by the Destructive Distillation of Wood, Peat, Pit-coal, Oil, Wax etc” ibid.. 9 (1805), 65–74; “Experi ments on Ammonia, and an Account of a New Method of Analyzing It, by Combustion With Oxygen and Other Gases,” in Philosophical Transactions of the Royal Society, 99 (1809), 430–449; “Additional Experiments on the Muriatic and Oxymuriatic Acids,” ibid. 102 (1812), 238–246; “On the Action of Finely Divided Platinum on Gaseous Mixtures, and Its Application to Their Analysis,” ibid., 114 (1824), 266–289; “Experiments on the Analysis of Some of the Aëriform Compounds of Nitrogen,” in iMemoirs of the Manchester Literary and Philosophical Society. 2nd ser., 4 (1824), 499–517; and “Experiments on the Disinfecting Powers of Increased Temperatures, With a View to the Suggestion of a Substitute for Quarantine,” in Philoophical Magazine, 10 (1831), 363–369; 11 (1832). 22–31. 205–207.

II. Secondary Literature. The main biographical source is W. C. Henry, “A Memoir of the Life and Writings of the Late Dr. Henry, in Memoirs of the Manchester Literary and Philosophical Society, 2nd ser., 6 (1842). 99–141: biographical sketches are in J. Wheeler, Manchester: Its Political, Social and Commercial History, Ancient and Modern (Manchester, 1836), pp. 495–498—it was written by J. Davies and published separately as Sketch of the Character of the Late William Henry (Manchester, 1836)—and in E. M. Brockbank, Sketches of the Lives and Work of the Honorary Medical Staff of the Manchester Infirmary (Manchester, 1904), pp. 235–240, with portrait. Brockbank also includes an article on W. C. Henry, pp. 273–275, with portrait. Also see W. V. Farrar, K. R. Farrar, and E. L. Scott, “The Henrys of Manchester,” in R.I.C. Reviews, 4 (1971), 35–47.

E. L. Scott