# Dictionary of National Biography, 1885-1900/Graham, Thomas (1805-1869)

​GRAHAM, THOMAS (1805–1869), chemist, was born in Glasgow 20 Dec. 1805. He was the son of a merchant and manufacturer, and the eldest of a family of seven, of whom only one survived him. In 1811 he was placed under Dr. Angus at the English preparatory school in Glasgow. In ​1814 he was transferred to the high school. In 1819 he entered Glasgow University, where he graduated as M.A. in 1824. He acquired scientific tastes under Dr. Thomas Thomson (then professor of chemistry) and Dr. Meikleham (natural philosophy). He declined to become a minister, as his father desired, in order to devote himself to science. After graduating at Glasgow, Graham spent ten years at the university of Edinburgh under Dr. Hope and Professor Leslie. While there he received 6l. for his first literary work, and spent it in presents to his mother and sisters. His correspondence with his mother shows their mutual devotion.
Returning to Glasgow, Graham, now thrown on his own resources, taught chemistry for some time in a laboratory in Portland Street. In 1829 he succeeded Dr. Clark as lecturer on chemistry at the Mechanics' Institution, and next year he was appointed professor of the same science at the Andersonian University. The post secured him a livelihood, and permitted him to engage in original research. After seven years of hard labour at his Glasgow post, Graham became professor of chemistry at University College, London (succeeding Dr. Edward Turner in 1837), and he held that chair with great distinction until 1855, when the government appointed him master of the Mint in succession to Sir John Herschel. He had for many years acted as non-resident assayer. Graham continued to preside at the Mint until his death at his residence in Gordon Square, London, 11 Sept. 1869. He was never married.
Graham was for ten years examiner in chemistry to the university of London; in 1846 he was a member of a commission appointed to report to the House of Commons on the ventilation of the new houses of parliament; in 1847 he was appointed by the board of ordnance to inquire into the various methods of casting guns; in 1851 he was appointed by government, with Professors Miller and Hofmann, to report on the purity of the water supplied by the various companies to the metropolis, and in the same year he acted as vice-president and reporter to the jury on chemical and pharmaceutical products at the Great Exhibition of 1851. In 1834 Graham received from the Royal Society of Edinburgh their Keith prize for his discovery of the law of the diffusion of gases. He was elected the first president of the Chemical Society on its establishment in 1840, and in the same year, and again in 1850, was awarded a gold medal by the Royal Society. In 1846 he became the first president of the Cavendish Society, established for the translation and publication of valuable works and papers on chemistry. For this society in 1848 Graham edited a translation of several important memoirs by German and French chemists under the title of ‘Chemical Reports and Memoirs.’
Graham was elected a fellow of the Royal Society in 1836; he was afterwards for six years on the council, and twice vice-president. In his latter days he was forced by growing infirmity to decline the presidency of the society. He delivered the ‘Bakerian lectures’ before the Royal Society in 1850 and 1854. He presided over the chemical section of the British Association at the Birmingham meeting of 1839, and was made D.C.L. of Oxford in 1853. He was a corresponding member of the Institute of France, and honorary member of the Academies of Sciences of Berlin, Munich, Turin, Washington, &c.
In 1842 Graham published his well-known text-book, ‘Elements of Chemistry,’ of which later editions appeared in 1856–8 and 1865; an American edition of this book was issued in 1852, and it was translated into German by Dr. Otto.
As a chemist Graham held ideas far in advance of his contemporaries. Before 1840 he had discovered and proved the polybasic character of phosphoric acid, proving that this acid forms several distinct compounds with water. The elementary body, hydrogen, he classed as a basylous metal, giving it the name of hydrogenium, a theoretical forecast based by him mainly on the alloy which hydrogen forms with palladium. It has since been justified by the condensation of hydrogen gas by means of pressure and cold into a bluish solid having a metallic ring. Graham even laid down the bold theory that all the (so-called) elements may be only forms of one primordial element.
Among his minor chemical researches were his experiments showing that the slow oxidation of phosphorus by air is arrested by the presence of even mere traces of olefiant gas, and that the spontaneous inflammability of phosphuretted hydrogen is due to the presence of a small proportion of nitrous acid. He studied carefully the so-called ‘water of crystallisation’ contained in many salts, and explained its presence and state of combination by chemical laws; his researches on the compounds of alcohol with salts (called alchoates) afforded valuable evidence of the analogy between alcohol and water.
Graham will be especially remembered for his discovery of the law of the diffusion of gases, which he showed to be inversely proportional to the square roots of their densities. The simple glass tube plugged at one end with plaster of Paris, which he introduced in these researches, is still universally em​ployed, and is known as ‘Graham's tube.’ His experiments on the passage of gases through small openings and through films of caoutchouc, &c., greatly extended our knowledge of the motions of molecules. He also studied the manner in which liquids permeate membranes (dialysis), and named those substances which had a high diffusibility crystalloids, and substances of a low diffusibility colloids; this research has an important bearing upon the phenomena of osmosis, and explains many facts connected with animal and vegetable life. The striking features of Graham's work are its originality and the simplicity of his methods, leading nevertheless to important and indeed fundamental results. In his later work Graham was ably assisted by Mr. W. C. Roberts-Austen, the present head of the Mint.
A bronze statue of Graham was placed in George Square, Glasgow, in 1872. His papers, &c., were collected by Dr. James Young, and printed (privately) in 1876, the volume having a preface by Dr. Angus Smith on ‘Graham and other Atomists.’ Altogether sixty-three papers by Graham on various scientific subjects appeared in different periodicals. The first, ‘On the Absorption of Gases by Liquids,’ in Thomson's ‘Annals of Philosophy’ for 1826; and the last, ‘Additional Observations on Hydrogenium,’ in ‘Proceedings of the Royal Society for 1869.’
W. J. H.