Faraday to Arthur-Auguste De La Rive   24 May 1858

Royal Institution | 24 May 1858

My dear De la Rive

I have received both yours¹; and sent them both to the Philosophical Magazine² to have the parts which are intended for publication published. I have no doubt they will appear in the next Number. I began to translate them; but they were taken from me that they might be done at once. I gave Tyndall your message who returns his own remembrances. The tubes which Gassiot & I worked³ with were those of his own construction not those of Geissler. Plucker brought some of Geisslers to London & shewed us some effects⁴. I have not, & cannot read, Plucker’s note⁵; but I did not understand from him that he claimed any merit in the observations of the ordinary effect of a magnet over the electric discharge through air, but for a special effect which occurs at the Negative metallic termination. When that (the discharge) takes place in a globe there is a diffused light in the globe or part of the globe, having its seat on the negative wire:- not the brighter; light - but another feebler one - When this is held between the strong poles of a very large & powerful magnet, they being about an inch apart,- all that kind of light collects itself into a plate, leaving the other parts of the globe dark.- Further, this plate has the Negative wire as a base or section & in fact is formed upon it; the breadth of the plate of light is formed by the length of the wire left exposed in the vacuum;- the thickness of the plate is coincident with the thickness of the wire; & the length of the plate is given by the globe, for its ends abut suddenly against the glass. This plate of light is always coincident with the lines of magnetic force and makes them visible as iron filings render them visible;- with this restriction, that no light is visible except for those lines of force which pass through the negative wire i.e though the discharging part of the negative wire for if half the wire be coated with an insulator no light lines of magnetic force pass though the coated part.

Plucker has shewn me this phenomenon not to its full extent but very decidedly & I understand that, that, was what he claimed.

I have not your letters at present; but I can understand your feelings about Plucker. Do not think that they surprize me. I profess to be a peacemaker & therefore say little about such matters, unless circumstances call for it:- but scient[if]ic morality is not altogether satisfactory.

Your kind expressions my dear friend delight me. I speak to very few friends (and to no other philosopher) as I do to you:- and why? because I have a trust in you in respect of matters beyond science. My kindest thoughts & remembrances (as also my wife’s) to Madame De la Rive. Others, still very kind, as they ought to be, to Your Son⁶, Marcet⁷, & other friends.

Ever My dear De la Rive | Yours | M. Faraday