Thomas Charles Hope

Thomas Charles Hope FRSE FRS PRCPE FFPSG (21 July 1766 – 13 June 1844) was a Scottish physician and chemist. He discovered the element strontium, and gave his name to Hope's Experiment, which shows that water reaches its maximum density at 4°C.
In 1815 Hope was elected as president of the Royal College of Physicians of Edinburgh (1815–19), and as vice-president of Royal Society of Edinburgh (1823–33) during the presidencies of Walter Scott and Thomas Makdougall Brisbane.
He founded the chemical prize at the University of Edinburgh.
Charles Darwin was one of Hope's students, and Darwin viewed his chemistry lectures as highlights in his otherwise largely dull education at the University.

Born in Edinburgh, the third son of Juliana Stevenson and surgeon and botanist Dr John Hope, he lived at High School Yards on the south side of the old town. He was educated next door to his house at the High School, the University of Edinburgh (MD 1787) and the University of Paris. At the university he was a student of Prof Joseph Black.

Hope was a nephew of the physician Alexander Stevenson FRSE.

He was appointed lecturer in chemistry at the University of Glasgow in 1787, and professor of medicine in 1789.

In January 1788, upon the proposal of John Walker, Daniel Rutherford and Alexander Monro, he was elected a Fellow of the Royal Society of Edinburgh.

In 1791-2 Hope discovered the chemical element strontium and named it after Strontian, the west highland village where he found strontianite. In the experiment that bears his name Hope determined the maximum density of water and explained why icebergs float.

Hope was elected a Fellow of the Royal Society of Edinburgh in 1788 and served as its Vice President from 1822 to 1833.

In 1795 Hope was selected by Joseph Black as his assistant (1795–1799) and eventual successor to the professorship of medicine and chemistry (1799–1843) at the University of Edinburgh. Hope’s goal was to more fully combine the practice of medicine with his chemical instruction.

In 1800 Hope won the annual Edinburgh Arrow archery competition.

In 1804 he became a member of the Highland Society.

In May 1810 he was elected a Fellow of the Royal Society of London.

From 1815 to 1819 he served as President of the Royal College of Physicians of Edinburgh.

Between 1824–40 Hope worked with scientists based in Poissy, France. With the town's major, Jean-François Senincourt, he tried to establish a university in the town. Within a few years their aims began to be realised as medical students crowded his lectures.

In the 1830s he is listed as living at 31 Moray Place, a huge townhouse in the Moray Estate on the western edge of Edinburgh's New Town.

In 1843 he resigned the professorship and died in Edinburgh in 1844.

• Hope, Thomas Charles. An account of a mineral from Strontian: and of a peculiar species of earth which it contains. p. 39. 
• Hope, Thomas Charles. "On the beads for ascertaining the specific gravity of liquid". Transactions of The Highland & Agricultural Society. Highland and Agricultural Society. 5 (1): 181. 
• Hope, Thomas Charles; Rutherford, Daniel; Duncan, Andrew (1796). Thomas Charles Hope lectures: on Chemistry. p. 280. 
• Telford, Thomas; Hope, Thomas Charles (1813). Reports on the means of improving the supply of water for the city of Edinburgh: and on the quality of the different springs in the neighborhood. Printed for Archibald Constable. p. 76. 
• Hope, Thomas Charles; University of Edinburgh (1833). Summary of a memorial to be presented to the Right Honourable the Lord Provost ...: respecting the institution of a professorship of practical chemistry in the University of Edinburgh. p. 17. 

Hope's Apparatus

Hope's apparatus consists of a vertical vessel full of water surrounded round the middle by a trough of cooling ice. Two thermometers, one above and one below the trough, measure the temperature of the water. It is designed to demonstrate that water reaches its maximum density at 4 degrees Celsius.

As the water in the central part of the vessel cools towards 4 degrees Celsius (and thus becomes denser) it sinks to the bottom of the vessel, displacing the warmer water. The lower thermometer will then read a constant 4 degrees. Further cooling towards zero degrees will cause the now less dense water to rise to the top of the vessel, where the upper thermometer will then read a constant zero degrees.