Faraday to William Whewell   9 February 1852

Royal Institution | 9, Feby 1852

My dear Sir

I hasten to thank you for your kind suggestions¹. The term Sphondyloid will I suppose answer every purpose I may want it for[.] I just enclose a figure² to make sure that I have not deceived[.] Supposing c.c a magnet as marked on the back of the paper, then various lines of force are shewn at the axis AB, and the lines DD.E.F. Now I have occasion to consider the solid which would be generated by the revolution of the area between F & C round the axis AB, or that produced by the like revolution of the area enclosed by E and C or by D and C, or even that enclosed between the lines of force D and E and such like. But in saying this I do not wish to give you the trouble of answering this letter. If you should however desire to do so tell me at the same time what the fair English meaning of the word Solenoid is meant to be[.]

Ever Your Very Obliged | M. Faraday

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