My dear Dr Tyndall,
Pray do not consider you are under the slightest obligation to me. I have simply done what I considered my duty as a member of the Council2 in voting the award for what I cannot but consider a most important discovery in Physical Science – One that must have an important bearing in that great question which has yet to be solved – the true cause of the variation of the magnetic needle.3
The great difficulty in the awarding of medals arises from the impossibility of fully discriminating between the conflicting claims of the different branches of science. That your discovery4 is in every respect worthy of the medal5 is universally acknowledged.
The road to fame is now fairly opened to you. I am confident you do not require such an incentive, but if I should in any way have cheered you on the path you have selected believe me when I say that I am richly rewarded.
Believe me | Yours truly | J.P. Gassiot.
RI MS JT/2/13b/633
LT Typescript Only
[8–9] November 1853: on 9 November, Tyndall noted the receipt of this letter stating, ‘This morning the following note was handed to me as I entered the Royal Institution’ (Journal, JT/2/13b/633). Since Gassiot wrote from London, it is likely he wrote the letter on 8 November or possibly the morning of 9 November.
the Council: see letter 0816, n. 7.
a most important … the magnetic needle: Gassiot was referring to the study of diamagnetism, which received significant attention during the mid-nineteenth century (see letter 0710, n. 7).
your discovery: Tyndall had received the Royal Medal for his 1851 article on diamagnetism, in which he discovered that ‘The entire mass of a magnetic substance is most strongly attracted when the attracting force acts parallel to that line which sets axial when the substance is suspended in the magnetic field; and the entire mass of a diamagnetic substance is most strongly repelled when the repulsion acts parallel to the line which sets equatorial in the magnetic field’. Furthermore, Tyndall noted that ‘The superior attraction and repulsion of the mass in a particular direction is due to the fact, that in this direction the material particles are ranged more closely together than in other directions; the force exerted being attractive or repulsive according as the particles are magnetic or diamagnetic’ (J. Tyndall, ‘On Diamagnetism and Magnecrystallic Action’, Phil. Mag. 2:10 [September 1851], pp. 165–88, on p. 188). See also Volume 3, ‘Introduction’; letters 0403 and 0418; and Jackson, ‘Tyndall and Diamagnetism’.
the medal: the Royal Medal (see letter 0815, n. 3).
Please cite as “Tyndall0821,” in Ɛpsilon: The John Tyndall Collection accessed on