Faraday to Robert Fitzroy   19 October 1861

[Royal Institution embossed letterhead] | 19 Octr. 1861

My dear Admiral

I have just come to town & found your instrument, letter, and the pamphlets - I have placed the instrument in the yard of the Institution in a place I think sufficiently open yet where no sun shines. We leave Hampton Court in a week or two & so I should not see it if it were there.

The instrument is an old friend of mine and used to take my attention very much when I was younger[.] It consists I think of Alcohol Water, Carbonate of Potassia and Hydrochlorate of Ammonia - but I do not know the proportions or perhaps all the materials - I could never make out more than that it was affected by changes of temperature - taking place with more or less rapidity - the time being important in relation to the appearances of the crystals.

If you can refer any of the changes to fog or to wind - independent of change of temperature you may perhaps discover something good in the matter¹[.]

Ever | My dear Admiral | Yours Truly | M. Faraday