Dear Sir.
I forward you ‘a report’ on electromagnetism.1
I have looked thro all the nos. of the Phil Mag. for 1850 and find no notice of Foucaults experiments on the velocity of light.2 This is a very interesting topic and directly I finish this note I shall plunge into it – it stands in the Comptes Rendus.3
I trust this will meet your approbation – you have given me a discretionary power and I must use it.
Before the expiration of another week I will send you some translations –
You should have received the accompanying report earlier had my investigations4 not detained me. I thought to manage so that a portion of every day might be devoted to the translations and Reports, but I find this plan wont work well. I can get on better when I devote my entire time to one thing or the other. for this reason I worked at the investigation up to last Saturday. then quietly closed it and turned my attention wholly to you – It is almost certain that I shall be able to send a good paper on magnetism for the March No 5 of the magazine. In a month I hope to have it in your hands – The results are very remarkable.
very sincerely yours | John Tyndall
9th January 1851
StBPL T&F, Authors’ letters
‘a report’ on electromagnetism: Tyndall, ‘Reports on the Progress of the Physical Sciences. Recent Researches on Electro-magnetism’, Phil. Mag., 1:3 (March 1851), pp. 194–205, discusses papers by Dub (Poggend. Annal., Sept 1848), Müller (Poggend. Annal., April 1850), and Buff and Zamminer (Annalen der Chemie, July 1850). This was the first in a series of ‘Reports on the Progress of the Physical Sciences’ that Tyndall wrote for Francis.
Foucault’s experiments: these showed that light travels more slowly through water than through air, and were important in establishing the wave theory of light over the corpuscular theory.
the Comptes Rendus: Tyndall discovered the article in German translation (letter 0457, n. 13) but translated it from the original French: Léon Foucault, ‘Méthode générale pour mesurer la vitesse de la luminère dans l’air les milieu transparent. Vitesses relatives de la luminère dans l’air et dans l’eau’, Comptes Rendus, 30 (January–June 1850), pp. 551–60. Within the week Tyndall had decided an abridged version would be sufficient (letter 0460).
my investigations: Tyndall was investigating the attraction between an electromagnet and a mass of iron in relation to the distance between them and the strength of the electromagnet. He first mentioned his intention to undertake such an investigation in letter 0458 (n. 10).
the March No: the article was not published until April (letter 0464, n. 2).
Please cite as “Tyndall0459,” in Ɛpsilon: The John Tyndall Collection accessed on 27 April 2024, https://epsilon.ac.uk/view/tyndall/letters/Tyndall0459