Royal Institution | 16th Mar. 1855.
My dear Sir,
A letter addressed as follows to Mr. Weber will be sure to find him:– Herrn Prof. Mr. Weber | Göttingen | Hanover. Germany.
The address of Dr Bence Jones | 30 Grosvenor Street | Grosvenor Square. London.
I am much obliged to you for your long and interesting letter,1 and have also to thank you for your memoir on Thermo-Electric currents.2 I handed his copy to Mr Faraday on the day it reached me.
Far be it for me to deny dogmatically the existence of a magnetic medium3 – I long for more light on the subject, and I have no doubt that the agitation of the question will greatly contribute to advance our knowledge of magnetism.
At the present time I regret to say I am obliged to banish the matter as far as possible from my thoughts, as too much pondering upon it and kindred subjects has thrown my brain into a state of confusion from which I must escape as soon as possible. Prof. Williamson of University Coll. has sent a paper to the Royal Society upon the subject of a medium.4 I heard it read last night, but did not feel able to enter upon the discussion.5 You will find that pure lead is diamagnetic, but it must be carefully handled. The fingers if not very clean contaminate the lead very soon. I always use an ivory blade to cut lead wax and such substances for diamagnetic experiments.
I hope to be able to send you an account of a great number of facts in connection with the subject of compression as soon as my lectures here are concluded.6 There is still a good deal to be done here and I have purposely avoided mingling the matter too much with my paper on polarity7 which is now in the hands of the Royal Society – The desire to keep this latter question as much as possible to itself, and not the want of material, has prevented me from entering more fully upon the subject of compression.
A short communication on the ‘medium’ from Mr Faraday will appear in the next number of the Phil. Mag.8
With best wishes | Believe me | Sincerely yours | John Tyndall
RI MS JT/1/5/1538–9
Transcript Only; Part of original letter at RI MS JT/1/T/1532
Part of the original manuscript exists (RI MS JT/1/T/1532) and has been used for transcription of ‘an ivory blade’ to end of letter.
your long and interesting letter: letter 1053.
your memoir on Thermo-Electric currents: probably W. Thomson, ‘Account of Researches in Thermo-Electricity’, Roy. Soc. Proc., 7 (1854–5), pp. 49–58.
the existence of a magnetic medium: which Thomson had supported in letter 1053.
Prof. Williamson … a medium: see letter 1057, n. 1.
the discussion: After hearing Williamson’s paper at the RS on 15 March, Tyndall wrote in his Journal: ‘My head was so bad that I felt unable to enter upon the discussion of the subject’ (RI MS JT/2/13c/736).
my lectures here are concluded: On 27 March 1855 Tyndall delivered the last RI lecture in the series ‘Electricity and Magnetism’.
my paper on polarity: Tyndall’s Bakerian Lecture (see letter 1029, n. 1) had yet to be refereed before publication in the Phil. Trans. Unknown to Tyndall, Thomson was one of his referees; see letter 1076, n. 4.
A short communication … Phil. Mag.: letter 1054.
Please cite as “Tyndall1057,” in Ɛpsilon: The John Tyndall Collection accessed on