George Biddell Airy to Faraday   3 December 1860

1860 Decr. 3

My dear Sir

I could not answer your note about Chance’s adjustments sooner¹.

My Report was made on April 7², and referred to a visit to Birmingham made a few days earlier.- The light being thrown upon a spar on which were marks adjusted by spirit-levelling, “I saw immediately that the dioptric part threw its light too high, and that the catadioptric parts threw their light too low .….. We raised the lamp-pillars 5/16 of an inch, and all was then right .… When the lamp-flame was burned, the faults exhibited themselves again. The height of the lamp-stand had been adjusted by the engineers’ usual rule.”

This Report is strictly the property of the Commission, which I suppose amounts to the same as its being yours.

I am, my dear Sir, | Yours most truly | G.B. Airy

Professor Faraday