Joseph Black

Scottish chemist

• Born: April 16, 1728
• Birthplace: Bordeaux, France
• Died: December 6, 1799
• Place of death: Edinburgh, Scotland

A pioneer of quantitative experimental chemistry, Black discovered carbon dioxide, the first gas to be isolated and have its properties systematically identified. He also proposed the theories of latent and specific heats and, as a gifted lecturer, raised the profile of chemistry to a philosophical and public science.

Early Life

Joseph Black’s father, John Black, came from a family of Scottish-Irish merchants. During the first half of the eighteenth century, John Black prospered as a factor in the wine trade. With success came prominence in Bordeaux society, and among the family’s closest friends was Montesquieu, president of the Sovereign Court of Bordeaux and author of The Spirit of the Laws (1748). Joseph’s mother, Mary, also was from a family of merchants. She had descended from the Gordons of Aberdeenshire, Scotland, and her lineage, like her husband’s, connected the world of eighteenth century trade to the world of the eighteenth century Enlightenment. Among Black’s cousins on his mother’s side was the Scottish social philosopher Adam Ferguson, author of An Essay on the History of Civil Society (1767). Joseph Black would later be best man at Ferguson’s wedding, and Ferguson an early biographer of Black.

Joseph Black was the ninth of fifteen children. Protestant outsiders in Catholic France, the large family compensated with close ties of mutual support. Both John Black and Mary Gordon generously provided for their children’s advancement, and an extensive family correspondence reveals that the children amply returned their affection. In 1740, Joseph Black was enrolled in a private school in Belfast, where he learned sufficient Latin and Greek to enter the University of Glasgow in the fall of 1744.

By the spring of 1748, Black had completed the undergraduate arts curriculum. The following fall he began the study of medicine. Black’s choice of medicine satisfied his father’s concern that his son get a professional education. It also satisfied Black’s own developing interests in natural philosophy. The choice proved fortunate. The previous year William Cullen had become professor of medicine at the University of Glasgow. At Glasgow, Cullen introduced a chemistry that was less subordinate to the pharmaceutical needs of medicine and more an autonomous science posing its own distinct questions—a chemistry, in short, that was more “philosophical.” The young Black quickly attracted the attention of the new professor of medicine. By 1749, Black had become Cullen’s laboratory assistant.

Life’s Work

In 1752, Joseph Black left Glasgow to do his medical thesis at the more prestigious University of Edinburgh. Published in June, 1754, the thesis was a milestone in Scottish philosophical chemistry. In June of 1755, Black presented his results to the Philosophical Society of Edinburgh. In the now classic paper, “Experiments upon Magnesia Alba, Quicklime, and Some Other Alcaline Substances” (pb. 1756), Black demonstrated that when heated, alkaline substances such as magnesium carbonate emitted a gas that Black called “fixed air.” This demonstration meant that “air” was not itself an element but instead made up of chemically distinct gases. It also meant that, contrary to previous understanding, a gas could combine with a solid. Furthermore, Black established that the gas he had discovered, fixed air, or carbon dioxide, was a by-product of fermentation and respiration, and that among its properties were mild acidity, a greater density than common air, and its not supporting life or combustion.

Black’s paper secured his scientific reputation and future career. When in 1755 Cullen became professor of chemistry at the University of Edinburgh, Black succeeded him at Glasgow as a professor of medicine and a lecturer in chemistry. Black now followed Cullen’s suggestions and turned to the study of heat. Black’s experiments on alkalis had been distinguished by their elegant design and quantitative rigor. So, too, were his observations on heat. Furthermore, historians of science sometimes credit him with the development of the ice calorimeter. Black’s observations soon led him to discover both latent heats and specific heats. The amount of heat absorbed or released by substances—say, water in freezing or water in vaporizing—without a change in temperature is a latent heat, and the different amounts of heat required to raise equal masses of different substances an equal interval in temperature are called specific heats.

Black never published his work on heat, but he did publicize it. As the rich collection of student notes makes clear, Black began his course on chemistry with a detailed presentation of his research on the effects of heat. Indeed, from the early 1760’s, Black largely abandoned the laboratory for the lecture hall. In 1766, with Cullen’s appointment as a professor of medicine, Black took up the chair of chemistry at Edinburgh. In his new position, Black increasingly focused on applied chemistry.

Already at Glasgow, Black had forged a close professional and, eventually, personal and business relationship with James Watt, who had been appointed instrument maker to the university. In 1769, Black loaned Watt the money needed to obtain a patent on his steam engine. As Watt himself affirmed, the methodological and theoretical background for his invention was laid by Black’s meticulous program of experimentation and his investigation of latent and specific heats. Now, in the 1770’s and 1780’s, Scottish agricultural improvers such as Henry Home, Lord Kames, sought Black’s chemical imprimatur for their proposals even as entrepreneurs sought Black’s advice on the metallurgy of coal and iron, the bleaching of textiles, and the manufacture of glass. Black also maintained a medical practice and in 1776 was the attending physician at the death of philosopher David Hume.

Black’s dedication to bringing together university and industry as well as philosophy and improvement was a trait he shared with the profusion of clubs in eighteenth century Scotland. He was a member not only of the Philosophical Society (later Royal Society) of Edinburgh but also of less formal civic groups, such as the Select Society or the Poker Club. Dearest to Black was the Oyster Club, weekly dinners with his closest friends William Cullen, the geologist James Hutton, and Adam Smith, the author of The Wealth of Nations (1776). Black’s friendship with Smith went back to their days as students and then new faculty members at the University of Glasgow. When Smith died in 1790, Black and Hutton served as his executors. In the mid-1790’s, Black’s own health, which had never been robust, began to fail. On December 6, 1799, just three days after he had managed to complete yet another course of lectures, Black died peacefully at his home in Edinburgh.

Significance

Joseph Black was an important precursor of the chemical revolution of the late eighteenth century. Britain’s preeminent professor of chemistry, Black was uniquely influential. Across his career, he introduced Scottish philosophical chemistry to as many as five thousand students. From the last decade of the eighteenth century until well into the nineteenth century, these students would edit chemical journals in Germany and hold chairs in chemistry at universities such as Cambridge, Oxford, Columbia, Princeton, and Yale.

During the 1790’s, Black was among the first to bring Antoine-Laurent Lavoisier’s reform of chemical nomenclature to an English-speaking audience. However, in 1789, the very year in which Lavoisier’s Traité élémentaire de chimie (Elements of Chemistry, in a New Systematic Order, Containing All the Modern Discoveries, 1790) was published, Lavoisier wrote Black acknowledging “the important revolutions which your discoveries have caused in the Sciences.” Black’s discovery of carbon dioxide opened the way for Joseph Priestley’s discovery of oxygen and Lavoisier’s own demonstration of oxygen’s role in calcination and combustion. To be sure, Black’s measurement of latent and specific heats still worked within a framework of a chemical theory that imagined heat as a caloric fluid that was lost when a body was cooled and gained when a body was heated. His measurements, however, also turned on a distinction between heat and temperature that laid the groundwork for nineteenth century thermodynamics and a conception of heat as kinetic energy.

From his earliest years in Bordeaux, Black stood at the crossroads between the great economic transformation that was the Industrial Revolution and the great cultural transformation that was the European Enlightenment. His life work balanced a calling to make the study of chemistry “philosophical” with a civic commitment to the “improvement” of Scotland. The balance that Black achieved was a model for chemistry’s continuing career in Britain as a public science—a career that culminated in Sir Humphry Davy’s lectures to the Royal Institution in the early nineteenth century. The balance that Black achieved also marked a critical moment in European cultural history, a moment before specialization would estrange the “two cultures” of the sciences and the humanities, a moment when chemistry remained a liberal vocation.

Bibliography

Black, Joseph. Experiments upon Magnesia Alba, Quicklime, and Some Other Alcaline Substances. Edinburgh: E. & S. Livingstone, 1966. A modern reprint of the 1756 publication of Black’s classic work. A brief, 46-page text.

Donovan, A. L. Philosophical Chemistry in the Scottish Enlightenment: The Doctrines and Discoveries of William Cullen and Joseph Black. Edinburgh: Edinburgh University Press, 1975. In the absence of a modern biography of Black, this work is the most authoritative account of Black’s life and contributions to chemistry.

Golinski, Jan. Science as Public Culture: Chemistry and Enlightenment in Britain, 1760-1820. New York: Cambridge University Press, 1992. Argues that Cullen and Black successfully established chemistry as an integral part of the civic culture of the Scottish Enlightenment.

Greenberg, Arthur. A Chemical History Tour. Hoboken, N.J.: John Wiley and Sons, 2000.

‗‗‗‗‗‗‗. The Art of Chemistry. Hoboken, N.J.: John Wiley and Sons, 2003. These two lavishly illustrated companion volumes situate Black within the development of chemical ideas in the eighteenth century.

Simpson, A. D. C., ed. Joseph Black, 1728-1799: A Commemorative Symposium. Edinburgh: Royal Scottish Museum, 1982. Includes short essays on Black’s life, medical practice, contributions to the study of heat, and the natural philosophical and institutional background to Black’s philosophical chemistry.