Conservation of Energy

Abstract

We saw in Chap. 1 that during the last quarter of the eighteenth century and first half of the nineteenth century, conservation of mass and conservation of energy were accepted as fundamental laws of nature by the scientific community. Conservation of mass can be attributed largely to quantitative investigations by Antoine-Laurent Lavoisier, who began an investigation of combustion in 1772 when the chemical nature of air was still a mystery. Recognition that energy is conserved occurred around 1840. Those developments are summarized in Chap. 1.

Supplemental Sources

Readers who enjoy reading the early history of science now have access through Google books and other Internet sources to digitized copies of many early works by renowned early investigators, such as Count Rumford, James Joule, Adair Crawford, W. O. Atwater, and F. G. Benedict, to mention only a few. Instead of trying to incorporate those references into the main body of the book, I have decided to list them with comments in a separate section.

“A Treatise on Heat” by Rev. Dionysius Lardner published in 1833 provides a good summary of the state of knowledge of heat at that time. The last chapter of the book summarizes arguments for and against the competing hypotheses that heat is either a material substance or a quality of matter.

Act I of The Edinburgh Review, No. CCXLIII, January, 1864, pp. 1–24, presents a balanced assessment by an unnamed author of three important papers dealing with discovery of the law of conservation of heat. Those papers are:

• Heat considered as a Mode of Motion: being a Course of Twelve Lectures delivered at the Royal Institution of Great Britain in 1862 by John Tyndall, F. R. S. London: 1863.

• On the Mechanical Equivalent of Heat by J. P. Joule, LL. D., F. R. S. Philosophical Transactions. Part I, 1850, p 61, London

• On Celestial Dynamics by Dr. J. R. Mayer of Heilbronn, Philosophical Magazine, 4th Series, Vol. XXV, p. 241, London, Dublin, and Edinburgh.

Tyndall’s lectures brought the relatively unknown work of Dr. J. Robert Mayer to the attention of British scientists; many of whom, however, felt that the lecture on Force slighted the work of Joule. Consequently, Tyndall’s assignment of priority for discovery of the law of conservation of energy to Mayer ignited a controversy that continued for many years. Principal supporters of Joule were P. G. Tait and William Thompson (Lord Kelvin). Some appreciation for the nature of the argument between Tait, Thompson, and Joule on one side and Tyndall on the other can be gained by reading excerpts from letters written to Thompson mostly between 1850 and 1870. Relevant sections of those letters now in possession of the Glasgow University Library can be found in “Background to the Joule-Mayer Controversy” by J. T. Lloyd, Notes and Records of the Royal Society of London, Vol. 25, No. 2, pp. 211–225 (1970).

One of Joule’s notebooks contained translations of two papers written in 1842 and 1843 by Mayer, which might suggest that Joule followed Mayer in developing his ideas about the conservation of energy. However, after carefully examining Joule’s notebook and reading a letter that Joule sent to Thompson in October, 1848, E. Mendoza and D. S. L. Cardwell concluded in “On a Suggestion Concerning the Work of J. P. Joule,” The British Journal for the History of Science, Vol. 14, No. 2, (Jul., 1981), pp. 177–180, that Joule probably first became aware of Mayer’s papers in 1848.

James Joule died on October 11, 1889 having lived his entire life in Broom Hill near Manchester. Following his death, Osborne Reynolds wrote a “Memoir of James Prescott Joule” which was published in the Memoirs and Proceedings of the Manchester Literary and Philosophical Society, Fourth Series, Sixth Volume (1892). Reynolds treatise provides a very perceptive description of Joule’s life and scientific work. Fenby’s more recent summary of early studies is also excellent.