Queenwood College Stockbridge Hants | 8th November 1851
Sir,
A sentence which occurs at the 329th page of your Discourse on the Study of Natural Philosophy induces me to hope that those of the enclosed memoirs which have reference to the ‘magnetism of crystalline bodies’ will interest you.1
I am afraid however that the theoretic notions as to the atomic mechanism of Iceland spar expressed at page 25 of the paper on the ‘Magneto-optic properties of Crystals’2 will not meet you approbation, as they differ from the hypothesis made use of by yourself in the 989th article of your treatise on Light.3 The reasoning at this place alluded to will not, however, be materially affected if we substitute spheroidal for rhomboidal molecules. We shall only have to suppose that the distance from end to end of the larger diameters, across the space which separates two adjacent molecules, to be greater than the distance between the ends of the short diameters. This view of course implies that the spheroids are not in absolute contact.
I ought to mention that the Testimonials were collected with a view of making application for the Professorship of Natural Philosophy in the University of Toronto; they have been authenticated by Dr William Francis Editor of the Philosophical Magazine.4
I remain Sir, | Your most obedient Servant | John Tyndall
Sir John F.W. Herschel Bart.5
RS HS 17.382
A sentence … interest you: ‘The magnetism of crystallized bodies ... has not hitherto been at all examined, but would probably afford very curious results’, Preliminary Discourse on the Study of Natural Philosophy (London: Longman, Rees, Orme, Brown, & Green, and John Taylor, 1831; first published as part of Lardner’s Cabinet Cyclopaedia), end of paragraph 367, on p. 329. Of the five papers Tyndall sent to Herschel with the preceding letter (0561), all, apart from the paper on the ‘Water-Jet’, discuss the ‘magnetism of crystalline bodies’ (most notably iron and bismuth). This letter seems to have been a more informal letter enclosed with letter 0561 and the larger package of papers.
paper … Crystals: cited letter 0403, n. 2.
your treatise on Light: six weeks previously Tyndall had asked Francis to find him a copy of the treatise (letter 0536); the 989th article was on p. 537 (cited ibid, n. 9).
have been authenticated … Magazine: Tyndall refers to two different processes of authentication. Here he refers to authentication by Francis that the translations of the German letters were reliable (compare letter 0538). The French ones had not been translated. In the previous letter (0561) he refers, we presume, to authentication that the printed testimonials matched the manuscripts.
Sir John . . . Bart.: As in the previous letter, Tyndall placed the addressee’s name at the bottom of the first page.
Please cite as “Tyndall0562,” in Ɛpsilon: The John Tyndall Collection accessed on 26 April 2024, https://epsilon.ac.uk/view/tyndall/letters/Tyndall0562