Julius Plücker to Faraday   8 February 1854

Bonn 8th of February | 1854.

My dear Sir!

I have been very much enjoied to receive your last kind letter¹; I’ll bring against forward my bad English for answering it.

Three weeks ago I gave two copies of a rather extensive² paper to my bookseller, one of them addressed to you, the other one to Prof. Wheatstone. Unhappily just the day before a parcel had departed for London. The next departure will take place, I hope, very soon. To this paper on magnetic and diamagnetic induction the table with curves, you speak of in your last letter, is annexed. The general conclusions are enumerated p.51-56. The fundame[n]tel fact, represented by the curves, is deduced from observations carefully made by the large Electromagnet and a delicate balance. Take as unity of the magnetic attraction that corresponding to the unity of intensity of the current; then you may find experimentally the attraction (y) corresponding to any given intensity [(]x). In this way you will get for different substances very different curves, but following all the same general law. (First set of curves). To the intensity of the current I substituted that of the acting power of the Magnetic pole (second set) and finally to the attraction, w[h]ich undergo the different substances, the intensity of the magnetism induced by the pole in these substances (third set of curves).

I operated only on gaz oxigene, melted phosphorous and different powders. The conclusions I anticipated with regard to bars of soft iron and steel (acier trempé) have been since plainly confirmed by experiment. Iron is nearly double as strong magnetic then steel but the magnetism of steel increases more rapidly then [sic] that of soft iron does. I am engaged in a new series of experimental results, w[h]ich will, I hope, confirm all my theoretical views.

Going on at the same time in my experimental Essays relatif to magnetisme and electromagnetism. I have just finished for the “Annalen” the first part of a paper on mixed vapours ³.

I hapily returned home last September. Since that time I worked as much as I could, not so much as I would. I have every day two or three public lectures to give; after having given them I feel myself rather tired. That is very hard work, allso, as soon as the lectures are closed, I want to make up my mind and therefore I run during one month or two through the world. Being returned home I feel myself restored.

Pray, sir, present my compliments to Mad. Faraday[.] With my best wishes for your health very truly

Yours | Plücker

Address: Professor Faraday | &c &c | Royal Institution | London