Joseph Black
Mezzotint engraving by James Heath after Sir Henry Raeburn
Born	16 April 1728 Bordeaux, France
Died	6 December 1799 Edinburgh, Scotland
Nationality	Scottish
Fields	Medicine, physics, and chemistry
Alma mater	University of Glasgow, University of Edinburgh
Academic advisors	William Cullen
Notable students	James Edward Smith
Known for	Latent heat, specific heat, and the discovery of carbon dioxide
Influenced	James Watt, Benjamin Rush[1]

Joseph Black FRSE FRCPE FPSG (16 April 1728 – 6 December 1799^[2]) was a Scottish physician and chemist, known for his discoveries of latent heat, specific heat, and carbon dioxide. He was professor of Medicine at University of Glasgow (where he also served as lecturer in Chemistry).

James Watt, who was appointed as philosophical instrument maker at the same university in 1775, consulted with Black on experiments with a small scale steam engine. Watt and Black also collaborated in a project to manufacture sodium hydroxide; however, Black was not known to have any business interest in the process, which did not enjoy commercial success.^[3] The chemistry buildings at both the University of Edinburgh and the University of Glasgow are named after Black.

Early years [edit]

Black was born in Bordeaux, France, where his father, who was from Belfast, Ireland, was engaged in the wine trade. His mother was from Aberdeenshire, Scotland, and her family was also in the wine business. Joseph had twelve brothers and sisters.^[4] He entered the University of Glasgow when he was eighteen years old, and four years later he went to Edinburgh to further his medical studies.

Analytical balance [edit]

A precision analytical balance

In about 1750, Joseph Black developed the analytical balance based on a light-weight beam balanced on a wedge-shaped fulcrum. Each arm carried a pan on which the sample or standard weights was placed. It far exceeded the accuracy of any other balance of the time and became an important scientific instrument in most chemistry laboratories.^[5]

In 1757, he was appointed Regius Professor of the Practice of Medicine at the University of Glasgow.

Latent heat [edit]

The world’s first ice-calorimeter, used in the winter of 1782–83, by Antoine Lavoisier and Pierre-Simon Laplace, to determine the heat evolved in various chemical changes, calculations which were based on Joseph Black’s prior discovery of latent heat.

In 1761 Black deduced that the application of heat to ice at its melting point does not cause a rise in temperature of the ice/water mixture, but rather an increase in the amount of water in the mixture. Additionally, Black observed that the application of heat to boiling water does not result in a rise in temperature of a water/steam mixture, but rather an increase in the amount of steam. From these observations, he concluded that the heat applied must have combined with the ice particles and boiling water and become latent. The theory of latent heat marks the beginning of thermodynamics.^[6] Black's theory of latent heat was one of his more-important scientific contributions, and one on which his scientific fame chiefly rests. He also showed that different substances have different specific heats.

This all proved important not only in the development of abstract science but in the development of the steam engine.^[7] The latent heat of water is large compared with many other liquids, so giving impetus to James Watt's successful attempts to improve the efficiency of the steam engine invented by Thomas Newcomen. Watt added a separate condenser, and kept the cylinder at the temperature of steam (by enclosing it in a steam-filled jacket) so saving a considerable amount of energy in avoiding the reheating of the cylinder at every cycle of the engine.

Carbon dioxide [edit]

Black also explored the properties of a gas produced in various reactions. He found that limestone (calcium carbonate) could be heated or treated with acids to yield a gas he called "fixed air." He observed that the fixed air was denser than air and did not support either flame or animal life. Black also found that when bubbled through an aqueous solution of lime (calcium hydroxide), it would precipitate calcium carbonate. He used this phenomenon to illustrate that carbon dioxide is produced by animal respiration and microbial fermentation.

Personal life [edit]

In 1757 or 1758 Black became a friend of James Watt, who first began his studies on steam power at Glasgow University in 1761. He provided significant financing and other support for Watt's early research on the steam engine. Black also was a member of the Poker Club and associated with David Hume, Adam Smith, and the literati of the Scottish Enlightenment. Black never married. He died in Edinburgh at the age of 71, and is buried there in Greyfriars Kirkyard. In 2011 scientific equipment believed to belong to Black was discovered during an archaeological dig at the University of Edinburgh.^[8]

See also [edit]

• Calorimetry
• Heat
• Pneumatic chemistry
• Thermochemistry

References [edit]

Further reading [edit]

• Ramsay, William (1918). The Life and Letters of Joseph Black. London: Constable.  at archive.org
• "JOSEPH BLACK and the discovery of carbon dioxide". The Medical Journal of Australia 44 (23): 801–2. June 1957. PMID 13440275. 
• "Joseph Black—rediscoverer of fixed air". JAMA 196 (4): 362–3. April 1966. doi:10.1001/jama.196.4.362. PMID 5325596. 
• Breathnach CS (October 1999). "Irish links of the multinational chemist Joseph Black (1728–1799)". Journal of the Irish Colleges of Physicians and Surgeons 28 (4): 228–31. PMID 11624012. 
• Breathnach CS (August 2000). "Joseph Black (1728–1799): an early adept in quantification and interpretation". Journal of Medical Biography 8 (3): 149–55. PMID 10954923. 
• Buchanan WW, Brown DH (June 1980). "Joseph Black (1728–1799): Scottish physician and chemist". The Practitioner 224 (1344): 663–6. PMID 6999492. 
• BUESS H (1956). "[Joseph Black (1728–1799) and the original chemical experimental research in biology and medicine]". Gesnerus (in German) 13 (3–4): 165–89. PMID 13397909. 
• Donovan A (November 1978). "James Hutton, Joseph Black and the chemical theory of heat". Ambix 25 (3): 176–90. PMID 11615707. 
• Eklund JB, Davis AB (October 1972). "Joseph Black matriculates: medicine and magnesia alba". Journal of the History of Medicine and Allied Sciences 27 (4): 396–417. PMID 4563352. 
• FOREGGER R (1957). "Joseph Black and the identification of carbon dioxide". Anesthesiology 18 (2): 257–64. doi:10.1097/00000542-195703000-00011. PMID 13411612. 
• FRACKELTON WG (November 1953). "Joseph Black and some aspects of medicine in the eighteenth century". The Ulster Medical Journal 22 (2): 87–99. PMID 13217111. 
• GUERLAC H (December 1957). "Joseph Black and fixed air. II". Isis 48 (154): 433–56. doi:10.1086/348610. PMID 13491209. 
• Lenard, Philipp (1950). Great Men of Science. London: G. Bell and Sons. p. 129. ISBN 0-8369-1614-X. 
• Perrin CE (November 1982). "A reluctant catalyst: Joseph Black and the Edinburgh reception of Lavoisier's chemistry". Ambix 29 (3): 141–76. PMID 11615908. 
• Ramsay, William (1905). The Gases of the Atmosphere. London: Macmillan. 

External links [edit]

• Black's experiments on Alkaline Substances
• Joseph Black – Biographical information
• Joseph Black – Encyclopædia Britannica, 1911
• Works by or about Joseph Black in libraries (WorldCat catalog)