William Whewell to Faraday   19 January 1846

Trin. Lodge, Cambridge | Jan. 19, 1846

My dear Sir,

Prof. Willis gave me an account of your experiment on light shown to the Council of the R.S. which I was sorry I was not there to see1. His account leads me to offer a suggestion which most likely you have anticipated, but it did not appear from what he said. I understood him that when you have deviated the plane of polarization by making contact, you prove and measure the change by turning the analyzer till you get the black spot. Now if before the light comes to the analyzer you interpose a double refracting crystal (uniaxial or biaxial) cut so as to give you the rings and cross, or the lemniscates, you will see the cross or the lemniscates move out of one position into another on making contact which I should think must be a more striking way of exhibiting the result. It is not likely that this has escaped you.

Willis told me also of your other experiments on magnetism of which I long to see a fuller account.

Believe me My dear sir | Yours very truly | W. Whewell

M. Faraday Esq

1
See RS CM 15 January 1846, 1: 512-3. Although at this meeting the letter of John Ross claiming priority in the discovery of the magneto-optical effect (see letter 1801) and letter 1803 were read, there is no indication, from the minutes, that any experiment was performed then.

Please cite as “Faraday1822,” in Ɛpsilon: The Michael Faraday Collection accessed on 9 May 2024, https://epsilon.ac.uk/view/faraday/letters/Faraday1822