Faraday to William Whewell   1 August 1850

Royal Institution | 1 Aug 1850

My dear Sir

I want a distinctive word, it may only be for a time for I am quite in uncertainty as to how finally the subject of Magnetism may settle down[.] But taking the Word Magnetic to represent the general action of the forces so called, and having already employed the word diamagnetic to represent that part of the general action which is manifest in bismuth phosphorous &c I want a word to represent the other & more know[n] part of the action manifested in Iron, Nickel Cobalt &c. The distinction is very important to me just now & I can hardly write my notes without it¹. Assuming the Earth as a Planet or a whole to represent one of these actions I have written Terro magnetic or Terra-magnetic & so made the following distinction in my notes

I feel that Terro & Dia are not in fair relation. Can you give me a better word, or considering the transitory state of Magnetic language is Terro magnetic or something like it admissible into printed papers for the present?

At present my head is full of visions: whether they will disappear as experiment wakens me up or open out into clear distinct views of the truth of nature is more than I dare say. But my hopes are strong.

Ever My dear Sir | Very Truly Yours | M. Faraday

Revd. Dr. Whewell | &c &c &c