29th January 1863
My dear Clausius
Accept my best thanks for the great trouble you have taken in looking over the proofs1 for me. Most of the parts to which you have referred are exactly those which I had marked in my memorandum book for future correction. With regard to the influence of the atomic number, I almost feared to bring it into the course itself, but my intention was to give an analysis at the end of the lecture of the results of Dulong2 & Petit,3 Regnault & Neumann.4 Your letter5 has caused me to reconsider the matter, and now I have introduced the subject in the text.
I am glad that you think me fair toward Mayer & Joule:6 it is my most earnest desire to give neither of them any just cause of complaint against me.
Goodbye dear Clausius | & believe me always | yours most sincerely | John Tyndall
RI MS JT/1/T/186
the proofs: for Heat as a Mode of Motion (see letter 1962, n. 1).
Dulong: Pierre Louis Dulong (1785–1838), a French physicist known for his study of the elasticity of steam and conduction of heat. He is especially noted for his research with Alexis Thérèse Petit, which resulted in the Law of Dulong and Petit (CDSB).
Petit: Alexis Thérèse Petit (1791–1820), a French physicist known for his work on heat and steam engines (see n. 2; CDSB).
Neumann: Franz Ernst Neumann (1798–1895), a German physicist and mathematician best known for Neumann’s law, which gave a quantitative expression to Faraday’s law of electromagnetic induction (CDSB).
Your letter: letter 1966.
fair toward Mayer & Joule: see letter 1962, n. 2.
Please cite as “Tyndall1969,” in Ɛpsilon: The John Tyndall Collection accessed on