Mechanical equivalent of heat
This article includes a list of general references, but it lacks sufficient corresponding inline citations. (July 2014) |
In the
History and priority dispute
Benjamin Thompson, Count Rumford, had observed the frictional heat generated by boring cannon at the arsenal in Munich, Bavaria, circa 1797 Rumford immersed a cannon barrel in water and arranged for a specially blunted boring tool. He showed that the water could be boiled within roughly two and a half hours and that the supply of frictional heat was seemingly inexhaustible.
Based on his experiments, he published "An Experimental Enquiry Concerning the Source of the Heat which is Excited by Friction", (1798), Philosophical Transactions of the Royal Society p. 102. This scientific paper provided a substantial challenge to established theories of heat and began the 19th century revolution in thermodynamics. The experiment inspired the work of James Prescott Joule in the 1840s. Joule's more exact measurements on equivalence were pivotal in establishing the kinetic theory at the expense of the caloric theory. The idea that heat and work are equivalent was also proposed by Julius Robert von Mayer in 1842 in the leading German physics journal and independently by James Prescott Joule in 1843, in the leading British physics journal. Similar work was carried out by Ludwig A. Colding in 1840–1843, though Colding's work was little known outside his native Denmark.
A collaboration between
Though a standardised value of 4.1860 J·cal−1 was established in the early 20th century, in the 1920s, it was ultimately realised that the constant is simply the
Both von Mayer and Joule met with initial neglect and resistance despite having published in leading European physics journals, but by 1847, a lot of leading scientists of the day were paying attention.
Also in 1847, Joule made a well-attended presentation at the annual meeting of
However, in 1848, von Mayer had first had sight of Joule's papers and wrote to the
joined to champion Joule's cause.However, in 1862, John Tyndall, in one of his many excursions into popular science and many public disputes with Thomson and his circle, gave a lecture at the Royal Institution entitled On Force[1] in which he credited von Mayer with conceiving and measuring the mechanical equivalent of heat. Thomson and Tait were angered, and an undignified public exchange of correspondence took place in the pages of the Philosophical Magazine, and the rather more popular Good Words. Tait even resorted to championing Colding's cause in an attempt to undermine von Mayer.
Though Tyndall again pressed von Mayer's cause in Heat: A Mode of Motion (1863) with the publication of Sir
Notes
- ^ The usage of terms such as work, force, energy, power, etc. in the 18th and 19th centuries by scientific workers does not necessarily reflect the standardised modern usage.
References
- ^ Lervig, P. Sadi Carnot and the steam engine:Nicolas Clément's lectures on industrial chemistry, 1823-28. Br. J Hist. Sci. 18::147, 1985.
Further reading
- Foucault, L. (1854) “Equivalent mécanique de la chaleur. M. Mayer, M. Joule. Chaleur spécifique des gaz sous volume constant. M. Victor Regnault”, Journal des débats politiques et littéraires, Thursday 8 June
- Lloyd, J.T. (1970). "Background to the Joule-Mayer Controversy". Notes and Records of the Royal Society. 25 (2): 211–225. S2CID 71802199.
- Sharlin, H.I. (1979). Lord Kelvin: The Dynamic Victorian. Pennsylvania State University Press. ISBN 0-271-00203-4., pp. 154–5
- Smith, C. (1998). The Science of Energy: A Cultural History of Energy Physics in Victorian Britain. Chicago University Press. ISBN 0-226-76421-4.
- Smith, C. (2004) "Joule, James Prescott (1818-1889)", Oxford Dictionary of National Biography, Oxford University Press, <http://www.oxforddnb.com/view/article/15139, accessed 27 July 2005> (subscription required)
- Zemansky, M.W. (1968) Heat and Thermodynamics: An Intermediate Textbook, McGraw-Hill, pp. 86–87
External links
- Media related to Mechanical equivalent of heat at Wikimedia Commons