Joseph Black
From Wikipedia, the free encyclopedia
| Joseph Black | |
|---|---|
|
|
| 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 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.
The chemistry buildings at both the University of Edinburgh and the University of Glasgow are named after Black.
Early Years
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.[3] He attended grammar school in Belfast from the age of 12 and entered the University of Glasgow in 1746 when he was eighteen years old, studying there for four years before spending another four at the University of Edinburgh, furthering his medical studies.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.[4]
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.
The theory of latent heat marks the beginning of thermodynamics.[5] 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.[6] The latent heat of water is large compared with many other liquids, so giving impetus to James Watt's attempts to improve the efficiency of the steam engine invented by Thomas Newcomen. Black and 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.
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.Edinburgh
In 1766, treading in the footsteps of his friend and former teacher at Glasgow, Black succeeded William Cullen as Professor of medicine and chemistry at the University of Edinburgh (Cullen had moved to Edinburgh in 1755). At this point he gave up research and devoted himself exclusively to teaching. In this he was very 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.Another reason for his lack of research was his poor constitution. The least undue strain, whether physical or mental, produced spitting of blood and it was only through great care that he maintained unbroken, though feeble, health. However from 1793 it visibly declined and he gradually withdrew more and more 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
Black 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 peacefully at his home in Edinburgh in 1799 at the age of 71 and is buried in Greyfriars Kirkyard.
In 2011 scientific equipment believed to belong to Black was discovered during an archaeological dig at the University of Edinburgh.[7]
