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Charles Brian Blagden
Blagden Charles (late 18th/early 19th century) by Mary Dawson Turner from a sketch by Thomas Phillips.
Born17 April 1748
Wotton-under-Edge, Gloucestershire
Died26 March 1820 (1820-03-27) (aged 71)
Arcueil, France
Known forStudies of perspiration and the freezing point of solutions
Awards Copley Medal (1788)

Sir Charles Brian Blagden FRS (17 April 1748 – 26 March 1820) [1] was an English physician and chemist. [2] He served as a medical officer in the Army (1776–1780) and later held the position of Secretary of the Royal Society (1784–1797). Blagden won the Copley Medal in 1788 and was knighted in 1792.

He died in Arcueil, France in 1820, and was buried at Père Lachaise Cemetery in Paris. [1]

Early life

Blagden was born in Wooten-under-Edge in Gloucestershire. He was a younger son of John Blagden (1715–1750) and Elizabeth Phelps (1716–1784). His family was part of the local textile industry. Of his youth, he stated that he "was denied the advantages of either public school or college education". [3] Nonetheless, he studied medicine at the University of Edinburgh and graduated as a doctor in 1768. He was elected a fellow of the Royal Society in 1772. In 1776, he became an army surgeon. During the American War of Independence, he served on the hospital ship HMS Pigot. [4] In 1780, he returned to a medical post in Plymouth but in late 1782 or early 1783 left for London to become an assistant and amanuensis to Henry Cavendish.


Blagden collection at the Royal Society

In June 1783, Blagden, then assistant to Henry Cavendish, visited Antoine Lavoisier in Paris and described how Cavendish had created water by burning "inflammable air". [5] Lavoisier's dissatisfaction with the Cavendish's "dephlogistinization" theory led him to the concept of a chemical reaction, which he reported to the Royal Academy on 24 June 1783, effectively founding modern chemistry. He was elected a Foreign Honorary Member of the American Academy of Arts and Sciences in 1789. [6] He was elected to the American Philosophical Society in 1789. [7]

Blagden experimented on human ability to withstand high temperatures. In 1775 he showed that human beings could withstand room temperatures as high as 260 degrees Fahrenheit (127 degrees Celsius). [8] In his report to the Royal Society in 1775, he was first Western scientist to officially recognise the role of perspiration in thermoregulation. [8] [9]

Blagden's experiments on how dissolved substances like salt affected the freezing point of water led to the discovery that the freezing point of a solution decreases in direct proportion to the concentration of the solution, now called Blagden's Law. [10]


  1. ^ a b Wilson, George (1851). The Life of the Hon. Henry Cavendish. London: Harrison and Son. p.  131. Charles Blagden pere.
  2. ^ For a summary of Blagden's life and work, see Jungnickel, Christa; McCormmach, Russell (1996). Cavendish. Philadelphia: American Philosophical Society. pp.  212–16. ISBN  978-0-87169-220-7. charles blagden experiment.
  3. ^ Getman, Frederick H. (1937). "Sir Charles Blagden, F. R. S.". Osiris. 3: 69–87. doi: 10.1086/368470. ISSN  0369-7827.
  4. ^ "Blagden, Sir Charles". The Oxford Dictionary of National Biography. Oxford: Oxford University Press. 23 September 2004. doi: 10.1093/ref:odnb/2553.
  5. ^ Brougham, Henry Lord (1839). "Historical Account of the Discovery of the Composition of Water". The Edinburgh New Philosophical Journal. 27 (54): 316–24.
  6. ^ "Book of Members, 1780–2010: Chapter B" (PDF). American Academy of Arts and Sciences. Retrieved 28 July 2014.
  7. ^ "Charles Blagden". American Philosophical Society Member History. American Philosophical Society. Retrieved 15 December 2020.
  8. ^ a b Blagden, Charles (1775). "Experiments and Observations in an Heated Room". Philosophical Transactions. 65: 111–23. doi: 10.1098/rstl.1775.0013. JSTOR  106183. S2CID  186214553.
  9. ^ Blagden, Charles (1775). "Further Experiments and Observations in an Heated Room". Philosophical Transactions. 65: 484–94. doi: 10.1098/rstl.1775.0048. JSTOR  106218. S2CID  186212940.
  10. ^ Mellor, Joseph William (1912). Modern Inorganic Chemistry. New York: Longmans, Green, and Company. p.  161. Blagden's Law.

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