George Biddell Airy to Faraday   7 June 1852

Royal Observatory | Greenwich | 1852 June 7

My dear Sir

At the late meeting of the Board of Visitors, there was a wish expressed by almost every member of the Board that I should confer with you respecting the reduction of our Magnetic Observations. The object - at least the ultimate object - of the reductions being understood to be, the reference of the phaenomena to their physical causes.

I do therefore by this writing take the first step in the conference, and I earnestly hope that you will respond to it.

Assuming that you will do so, I now proceed to consult you on the best method of proceeding. And I will beg leave to commence with the following statement.

We have, as you probably know, very full and accurate records (such as I firmly believe to be unequalled in the world) of the constant changes of magnetic elements, formed by our photographic apparatus. Without examination of these, I do not think that any body can form an accurate notion of the phaenomena that stand to be explained. There are, as is commonly believed, the regular phaenomena of

Annual variation

Diurnal variation

but there are also the anomalous phaenomena of

Fret

Irregularity

Storms

which are so much greater in magnitude than the others, that I have no confidence (and in this I was supported by several members of the Board) in deductions applying to the so called regular phaenomena until the irregular ones are cleared out of the way.

Now would you like to look over a volume or two (say a years collection) of our Photographs, and form a general notion of the things? On receiving your assent, I will send you the bound collections. And then, in due time, would you make an appointment for me to wait on you and talk over the matter? - Or do you see any better course?

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

Michael Faraday Esq | &c &c &c