Hope, Thomas Charles
Hope, Thomas Charles
(b. Edinburgh, Scotland, 21 July 1766; d. Edinburgh, 13 June 1844)
The successor to Joseph Black as professor of chemistry at Edinburgh University, Hope considered the teaching of science, rather than its extension by original research, to be his vocation. Nevertheless, he is remembered chiefly for his contributions to the discovery of strontium and for his conclusive demonstration that water reaches its maximum density just above its freezing point.
The third son of John Hope, regius professor of botany at Edinburgh, and the former Juliana Stevenson, Hope entered the university at the age of thirteen. He became very proficient in botany and was a strong but unsuccessful candidate for the chair when his father died in 1786. After receiving the M.D. in 1787 he became successively lecturer in chemistry, assistant professor of medicine (1789), and professor of medicine (1791) at Glasgow. In 1795 Hope was chosen by Black, whose health was failing, as assistant and potential successor at Edinburgh; Black died in 1799, and Hope gave his last series of lectures in 1843. He was elected a fellow of the Royal Society in 1810.
In 1790 Adair Crawford presented the first intimation that the mineral now called strontianite (first found near Strontian, Scotland), previously thought to be a form of barium carbonate, contained a hitherto unknown “earth.” The substance was examined by a number of mineralogists over the next few years; but the fullest investigations were those, carried out quite independently, by Hope and M. H. Klaproth. Hope clearly established the intermediacy of strontia in relation to lime and baryta, foreshadowing the more explicit formulation of this particular triad by J. W. Döbereiner in 1829. The metals calcium, strontium, and barium were isolated by Davy in 1808.
The peculiar expansion of water had been noted in the seventeenth century; but Hooke, Dalton, and others were skeptical. Hope clearly showed that water is at its densest at a little above 39°F. “Hope’s experiment” has become a classic and may be found in many physics textbooks.
In spite of a pompous and affected manner, Hope was a gifted and popular lecturer. His teaching was seriously weakened by a failure to provide facilities for, or to encourage, practical work.
I. Original Works. Hope’s two important papers are “Account of a Mineral From Strontian, and of a Peculiar Species of Earth Which It Contains,” in Transactions of the Royal Society of Edinburgh, 4 (1798), 3–39; and “Experiments and Observations Upon the Contraction of Water by Heat at Low Temperatures,” ibid., 5 (1805), 379–405. His papers are listed in Royal Society Catalogue of Scientific Papers, III (London, 1869), 426–427.
II. Secondary Literature. Biographies are T. S. Traill, “Memoir of Dr. Thomas Charles Hope, Late Professor of Chemistry in the University of Edinburgh,” in Transactions of the Royal Society of Edinburgh, 16 (1848), 419–434; and J. Kendall, “Thomas Charles Hope, M.D.,” in Endeavour, 3 (1944), 119–122. The discovery of strontium is dealt with briefly in E. M. Weeks, Discovery of the Elements, 7th ed., rev. by H. M. Leicester (Easton, Pa., 1968), pp. 491–495; and more fully by J. R. Partington, “The Early History of Strontium,” in Annals of Science, 5 (1947), 157–166; and 7 (1951), 95–100, which deals more specifically with Hope’s contribution.
Reminiscences of Hope as a lecturer are in G. P. Fisher, Life of Benjamin Silliman, I (New York, 1866), 163–166; and a recent study of one aspect of Hope’s career is J. B. Morrell, “Practical Chemistry in the University of Edinburgh,” in Ambix, 16 (1969), 66–80. See also R. H. Cragg, “Thomas Charles Hope (1766–1844),” Medical History, 11 (1967), 186–189.
E. L. Scott