William Scoresby to Faraday   6 March 1851¹

Torquay, 6th March 1851.

Dear Dr. Faraday,

Whilst you are working so successfully on great laws & phenomena, I am, as time admits, doing a little, or rather trying to do something, though in the matter to which I refer in this note, the results are merely negative.

I have been trying the effect of the magnetic condition, in iron, as also of a galvanic current, with a view to the inquiry, whether any alterations in dimensions are thereby occasioned? My experiments, within the limits of observation in my apparatus, indicate no sensible effect, except what belongs to temperature. The value of my scale, however, observed by reflection in a mirror, is not well determined on account of the different points of contact & leverage - the lengths not being easily determinable. I wish therefore to verify my present impression, as to the value by the interposition of a disc or slip of metal of known thickness. I thought that you, perhaps, might be able to advise me how I could procure such a disc or plate? The Mint has a fine rolling apparatus, which I believe has values attached? But you, possibly, might have some little bit of sheet metal of known dimensions. What I require is a disc or “blank” or slip of small size - that of a shilling² is large enough, and of a thickness of 1/50th or any where from 1/50th to 1/100th of an inch. This I could interpose between two of my bars which would verify or correct my present estimations.

The apparatus which I constructed myself here, works so beautifully, that a degree of temperature produces near 1/4 inch movement in the reflected scale - consequently the quarter of a degree of temperature, or the alteration in length due to that small quantity, is easily determinable.

Thinking the experiments might not be altogether uninteresting, though negative as to results, I am preparing a paper for the Royal Soc. thereon³.

I am, my Dear Dr. Faraday, | Yours very faithfully, | Willm Scoresby