Thorncliff Old Trafford | Manch[este]r 21 July 1862
Dear Sir,
I thank you for your kindness in sending me the second part of your admirable researches on radiation & absorption of heat by gases & vapours.1 It is almost impossible to exaggerate their interest as setting forth original facts of most extensive application to the phenomena of nature. I thank you also for your R[oyal]. Inst[itutio]n lecture2 on the subject of which you will see I have made one or two remarks in the Phil[osophical] Mag[azi]ne.3 I think in a case like that of the Equiv[alen]t of Heat the experimental worker rather than the mere logical reasoner (however valuable the latter) must be held as the establisher of a theory.4 I have determined the mech[anica]l equivalent in nearly a dozen ways, and the figure I arrived at in 1849 has not yet been altered or corrected.5 Mr Dyer6 of this town was I believe the first man who noticed the rise of temp[eratur]e on shaking water, but he applied it to nothing—in fact explained away what he saw.
Believe me Dear Tyndall | Yours always truly | J. P. Joule
RI MS JT/1/J/138
RI MS JT/1/TYP/2/662
second part of your admirable researches: J. Tyndall, ‘On the Absorption and Radiation of Heat by Gaseous Matter. Second Memoir’, Phil. Trans., 152 (1862), pp. 59–98.
your R[oyal]. Inst[itutio]n lecture: see letter 1902, n. 4.
Phil[osophical] Mag[azi]ne.: James P. Joule, ‘Note on the History of the Dynamical
Theory of Heat’, Phil. Mag., 24 (1862), pp. 121–3.
the experimental worker rather than the mere logical reasoner… theory: Joule here reasserts his priority over that of Mayer, who Tyndall had advanced as in fact the first to arrive at the mechanical equivalent of heat. This was to become a long-running dispute between Tyndall and Joule that occupied Tyndall throughout the period covered by this volume. See the volume introduction for further commentary.
figure I arrived at in 1849 has not yet been altered or corrected: a reference to Joule’s
paper, ‘On the Mechanical Equivalent of Heat’, in Phil. Trans. delivered in 1849 and
published in 1850. In this paper he specified the numerical value for the amount of mechanical
work required to produce a unit of heat. J. P. Joule, ‘On the Mechanical Equivalent of
Heat’, Phil. Trans., 140 (1850), pp. 61–82.
Mr Dyer: probably Joseph Chessborough Dyer (1780–1871), an American-born inventor who moved to England in 1811, introducing several American inventions to England. He was a member of the Institution of Civil Engineers and the Literary and Philosophical Society of Manchester, and was involved in the foundation of the Royal Manchester Institution in 1823. In 1842, following the death of his wife, Chessborough sold his machine works in Manchester to Parr, Curtis, & Madeley. Later, he published pamphlets for the abolitionist cause (ODNB).
Please cite as “Tyndall1914,” in Ɛpsilon: The John Tyndall Collection accessed on