Joseph Black
Portrait by Sir Henry Raeburn in 1790
Born(1728-04-16)16 April 1728
Bordeaux, France
Died6 December 1799(1799-12-06) (aged 71)
Edinburgh, Scotland
Alma materUniversity of Glasgow
University of Edinburgh
Known forThe discovery of Magnesium
carbon dioxide
Latent heat
specific heat
Invention of Analytical balance
Scientific career
FieldsMedicine, physics, chemistry
InstitutionsUniversity of Edinburgh
Academic advisorsWilliam Cullen
Notable studentsJames Edward Smith
Thomas Charles Hope
Joseph Black plaque by James Tassie, Hunterian Museum, Glasgow

Joseph Black (16 April 1728 – 6 December 1799) was a Scottish physicist and chemist, known for his discoveries of magnesium, latent heat, specific heat, and carbon dioxide. He was Professor of Anatomy and Chemistry at the University of Glasgow for 10 years from 1756, and then Professor of Medicine and Chemistry at the University of Edinburgh from 1766, teaching and lecturing there for more than 30 years.[1]

The chemistry buildings at both the University of Edinburgh and the University of Glasgow are named after Black.

Early life and education

Black was born "on the banks of the river Garonne" in Bordeaux, France, the sixth of the 12 children of Margaret Gordon (d. 1747) and John Black. His mother was from an Aberdeenshire family that had connections with the wine business and his father was from Belfast, Ireland, and worked as a factor in the wine trade.[2] He was educated at home until the age of 12, after which he attended grammar school in Belfast. In 1746, at the age of 18, he entered the University of Glasgow, studying there for four years before spending another four at the University of Edinburgh, furthering his medical studies. During his studies he wrote a doctorate thesis on the treatment of kidney stones with the salt magnesium carbonate.[3]

Scientific Studies

Chemical principles

Like most 18th-century experimentalists, Black's conceptualisation of chemistry was based on five principles of matter: Water, Salt, Earth, Fire and Metal.[4] He added the principle of Air when his experiments showed the presence of carbon dioxide, which he called fixed air, thus contributing to pneumatic chemistry.

Black's research was guided by questions relating to how the principles combined with each other in various different forms and mixtures. He used the term affinity to describe the force that held such combinations together.[5] Throughout his career he used a variety of diagrams and formulas to teach his University of Edinburgh students how to manipulate affinity through different kinds of experimentation.[6]

Analytical balance

A precision analytical balance

In about 1750, while still a student, 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.[7]

Latent heat

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

In 1761, he 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.[8]

The theory of latent heat marks the beginning of thermodynamics.[9] 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.

The theory ultimately proved important not only in the development of abstract science but in the development of the steam engine.[10] Black and James Watt became friends after meeting around 1757 while both were at Glasgow. Black provided significant financing and other support for Watt's early research in steam power. Black's discovery of the latent heat of water would have been interesting to Watt,[11] informing his attempts to improve the efficiency of the steam engine invented by Thomas Newcomen and develop the science of thermodynamics.

Carbon dioxide

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.


In 1766, treading in the footsteps of his friend and former teacher at the University of Glasgow, Black succeeded William Cullen as Professor of Medicine and Chemistry at the University of Edinburgh (Cullen had moved to Edinburgh in 1755). His position at Glasgow University was filled by Alexander Stevenson.[12]

At this point he gave up research and devoted himself exclusively to teaching. In this he was successful with audience attendance at his lectures increasing from year to year for more than thirty years. His lectures had a powerful effect in popularising chemistry and attendance at them even came to be a fashionable amusement.

Black was widely recognised as one of the most popular lecturers at the University. His chemistry course regularly attracted an exceptionally high number of students, with many attending two or three times. In addition to regularly introducing cutting-edge topics and meticulously selecting visually impressive experiments, Black employed a wide array of successful teaching tools that made chemistry accessible to his students (many of whom were as young as 14 years old).[13][14] His students came from across the United Kingdom, its colonies and Europe, and hundreds of them preserved his lectures in their notebooks and disseminated his ideas after they left university.

He became one of the principal ornaments of the University; and his lectures were attended by an audience which continued increasing from year to year, for more than thirty years. It could not be otherwise. His personal appearance and manners were those of a gentleman, and peculiarly pleasing. His voice in lecturing was low, but fine; and his articulation so distinct, that he was perfectly well heard by an audience consisting of several hundreds. His discourse was so plain and perspicuous, his illustration by experiment so apposite, that his sentiments on any subject never could be mistaken even by the most illiterate; and his instructions were so clear of all hypothesis or conjecture, that the hearer rested on his conclusions with a confidence scarcely exceeded in matters of his own experience.[15]

On 17 November 1783 he became one of the founders of the Royal Society of Edinburgh.[16] From 1788 to 1790 he was President of the Royal College of Physicians of Edinburgh.[17] He was a member of the revision committee for the editions of the college's Pharmacopoeia Edinburgensis of 1774, 1783, and 1794. Black was appointed principal physician to King George III in Scotland.

Black's research and teaching were reduced as a result of poor health. From 1793 his health declined further and he gradually withdrew from his teaching duties. In 1795, Charles Hope was appointed his coadjutor in his professorship, and in 1797, he lectured for the last time.

Personal life

Joseph Black's grave in Greyfriars Kirkyard in Edinburgh

Black was a member of The Poker Club. He was 1st cousin, great friend and colleague to Adam Ferguson FRSE who married his niece Katherine Burnett in 1767, and associated with David Hume, Adam Smith, and the literati of the Scottish Enlightenment. He was also close to pioneering geologist James Hutton.[18]

In 1773 he is listed as living on College Wynd on the south side of the Old Town.[19] In the 1790s, he used Sylvan House in Sciennes as a summer retreat. A plaque, unveiled in 1991, commemorates his occupancy of the house.[20]

Black never married. He died peacefully at his home 12 Nicolson Street[21] in south Edinburgh in 1799 at the age of 71 and is buried in Greyfriars Kirkyard. The large monument lies in the sealed section to the south-west known as the Covenanter's Prison.

In 2011, scientific equipment believed to belong to Black was discovered during an archaeological dig at the University of Edinburgh.[22]

His house, a flat at 12 Nicolson Street very close to the Old College, still exists, but lacks any plaque to indicate his presence.

See also


  1. ^ Guerlac, Henry (1970–1980). "Black, Joseph". Dictionary of Scientific Biography. Vol. 2. New York: Charles Scribner's Sons. pp. 173–183. ISBN 978-0-684-10114-9.
  2. ^ Lenard, Philipp (1950). Great Men of Science. London: G. Bell and Sons. p. 129. ISBN 0-8369-1614-X. (Translated from the second German edition.)
  3. ^ Antonis Modinos (15 October 2013). From Aristotle to Schrödinger: The Curiosity of Physics. Springer International Publishing. p. 134. ISBN 978-3-319-00749-6.
  4. ^ Eddy, Matthew Daniel (2008). John Walker, Chemistry and the Edinburgh Medical School, 1750-1800. London: Routledge.
  5. ^ Eddy, Matthew Daniel (2014). "How to See a Diagram: A Visual Anthropology of Chemical Affinity". Osiris. 29: 178–196. doi:10.1086/678093. PMID 26103754. S2CID 20432223.
  6. ^ Eddy, Matthew Daniel. "Useful Pictures: Joseph Black and the Graphic Culture of Experimentation". In Robert G. W. Anderson (Ed.), Cradle of Chemistry: The Early Years of Chemistry at the University of Edinburgh (Edinburgh: John Donald, 2015), 99-118.
  7. ^ "Equal Arm Analytical Balances". Archived from the original on 13 May 2017. Retrieved 8 March 2008.
  8. ^ Chisholm, Hugh, ed. (1911). "Black, Joseph" . Encyclopædia Britannica. Vol. 4 (11th ed.). Cambridge University Press.
  9. ^ Ogg, David (1965). Europe of the Ancien Regime: 1715–1783. Harper & Row. pp. 117 and 283.
  10. ^ Ogg, David (1965). Europe of the Ancien Regime: 1715–1783. Harper & Row. p. 283.
  11. ^ James Patrick Muirhead (1859). The Life of James Watt, with selections from his correspondence (2nd edition, revised). D. Appleton & Company. p. 78. ISBN 9780598483225.
  12. ^ Medical and Philosophical Commentaries 1792
  13. ^ Eddy, Matthew Daniel (2014). "How to See a Diagram: A Visual Anthropology of Chemical Affinity". Osiris. 29: 178–196. doi:10.1086/678093. PMID 26103754. S2CID 20432223.
  14. ^ Eddy, Matthew Daniel. 'Useful Pictures: Joseph Black and the Graphic Culture of Experimentation', in Robert G. W. Anderson (Ed.), Cradle of Chemistry: The Early Years of Chemistry at the University of Edinburgh. Edinburgh: John Donald. pp. 99–118.
  15. ^ The National Cyclopaedia of Useful Knowledge Vol III, (1847), London, Charles Knight, p.382.
  16. ^ "Former Fellows of the Royal Society of Edinburgh 1783-2002 Biographical Index" (PDF). Royal Society of Edinburgh. Retrieved 13 November 2021.
  17. ^ "College Fellows: curing scurvy and discovering nitrogen". Royal College of Physicians in Edinburgh. 14 November 2014. Retrieved 4 November 2015.
  18. ^ Records of the Clan and Name of Ferguson 1895 p.138 note 1 accessed 22 Dec 2018
  19. ^ Edinburgh Post Office directory 1773
  20. ^ Cant, Malcolm (2001). Marchmont, Sciennes and the Grange. Edinburgh: M. Cant Publications. p. 6. ISBN 0952609959.
  21. ^ Williamsons Edinburgh Directory 1798
  22. ^ "Dig finds treasured tools of leading 18th century scientist". The Scotsman. 28 June 2011. Archived from the original on 18 April 2012.

Further reading