Andrews, Thomas

(b. Belfast, Ireland, 19 December 1813; d. Belfast, 26 November 1885) chemistry.

The eldest son of Thomas John Andrews, a linen merchant, and Elizabeth Stevenson, Andrews was first educated at the Belfast Academy and the Belfast Academical Institution. After working for a short time in his father’s office in 1828, he studied chemistry at Glasgow and then spent a short period in Dumas’s laboratory in Paris in 1830. He studied medicine for four years at Dublin and for a year at Edinburgh, where he received the M.D. in 1835. On qualifying, he established a medical practice in Belfast and at the same time was appointed the first professor of chemistry at the Belfast Academical Institution. In 1842 Andrews married Jane Walker, and three years later gave up both his medical practice and his teaching post to become the first vice-president of Queen’s College, Belfast. He also became professor of chemistry at Belfast when teaching started in 1849, and did not retire until 1879. In June 1849 he was elected a fellow of the Royal Society.

Andrews was noted for his manipulative skill and ingenuity in solving practical problems; he constructed much of his own apparatus. He was a good university administrator and keenly interested in social and political problems, He published two pamphlets, Studium generale and The Church in Ireland, which he called “chapters of contemporary history.”

After some early work extending Schönbein’s discoveries regarding passivity of metals, Andrews turned his attention to thermochemistry and, in a series of papers read in the period 1841–1848, gave details of experiments, many of them remarkably accurate, on heats of neutralization, heats of formation of water and other oxides and of metallic halides, and on the heat evolved when one metal replaces another in solutions. His work was begun at about the same time as that of Hess, but although they obtained similar results, their conclusions did not always agree.

Andrews subsequently turned his attention to the problem of the constitution of ozone. This had been investigated by a number of chemists, including Schöonbein, its discoverer. Its nature was still unknown, however, and it was by no means certain that the ozone obtained from different sources was one and the same substance; it was thought by some to contain hydrogen. Andrews says his researches extended over four or five years, and he finally reached the conclusion that all the supposed varieties of ozone were identical and that it was in fact oxygen in an altered or allotropic condition. The investigation was continued in collaboration with P. G. Tait, but their attempts to determine the density of ozone proved abortive. This was because of their assumption that those reagents which were known to remove the ozonic properties from a mixture of ozone and oxygen actually combined with the ozone; they did not realize that the reagent removed an atom of oxygen from a molecule of ozone, leaving a molecule of oxygen, so that no volume change took place. Since a measurable weight of ozone thus appeared to occupy zero volume, it seemed that its density was infinite. This perplexing result (which they came near to explaining toward the end of their joint paper of 1860) led, however, to a proposal of the true solution by Odling in 1861; and the suggested formula O₃ was eventually established by Jacques Soret in 1866 and confirmed by b.c. Brodie in 1872.

Andrews is best known for his studies on the continuity of the gaseous and liquid states, and in particular for his discovery of the critical temperature of carbon dioxide in 1861. His researches formed the subject of the Bakerian lectures for 1869 and 1876; a further paper was published posthumously in 1887. The first printed account of his work appeared as a result of a communication from Andrews to W. A. Miller, who published it in his textbook(1863). After a graphic description of the appearance of carbon dioxide in a state intermediate between gas and liquid, he concludes “that there exists for every liquid a temperature at which no amount of pressure is sufficient to retain it in the liquid form” (in W. A. Miller, Elements of Chemistry, 3rd ed. [London, 1863], I, 328–329). He expressed the full implications of his discovery some ten years after his first experiments when, in 1871, he wrote: “We may yet live to see, or at least we may feel with some confidence that those who come after us will see, such bodies as oxygen and hydrogen in the liquid, perhaps even in the solid state” (Scientific Papers, p. Ix).

BIBLIOGRAPHY

1. Original Works. Studium generale (London, 1867) is severely critical of the policy of awarding external degrees without compulsory residence; Andrews argues for the establishment of more universities but insists they should be independent of each other and free from governmental or ecclesiastical control. The Church in Ireland (London, 1869) is a plea for religious toleration and an argument for the disestablishment of the Church of Ireland. Andrews’ papers, with their original locations, are collected in The Scientific Papers of the Late Thomas Andrews, M. D., F. R.S., With a Memoir, P. G. Tait and A. Crum Brown, eds.(London, 1889). See also The Royal Society Catalogue of Scientific Papers, I(1867), 69–70.

II. Secondary Literature. The memoir by Tait and Crum Brown (see above) is a biographical sketch and an appraisal of Andrews’ work; it contains numerous extracts from his letters. See also Hugo Müller, in Journal of the Chemical Society, 49 (1886), 342–344. A more recent estimate of his work is C. L. Wilson,” The Queen;s University of Belfast,” in Journal of the Royal Institute of Chemistry, 81 (1957), 16–29, but he is concerned primarily with the history of the chemical school at Belfast University. See also Henry Riddell, in Proceedings of the Belfast Natural History and Philosophical Society(1921), 107–138.

E. L. Scott