Peyron to Faraday   20 August 1841¹

Paris 20 August 1841

To Doctor Faraday F.R.S.

Sir

My friends Breguet² and professor Masson³ in investigating the best way of rendering useful the induced currents, in the construction of the electrico-magnetical machine of which I exposed to you, last year the general plan⁴, have obtained some results⁵ which appear to me a complement in some instances - of your own researches and of those of professor Henry⁶. This reason induces me to give you a short account of the chief points of their experiments. As soon as a machine will be constructed - I shall take the liberty of making you know if the result answers to my hope - and to ask your advice if it does not.

The voltaic apparatus used is the modification of professor Daniell's constant battery⁷ in which the earthen cups are replaced by a membrane separating a copper cylinder from a zinc one - which surrounds it. Each copper cylinder is 8 inches in height and 2 1/2 in Diameter. Each Zinc 8 on 3 and 9 lines. A solution of sulfate of copper fills the first - the second is only plunged in pure water.

The helix is formed of two copper wires twice covered with cotton threads - of 1/10 of inch in diameter and 605 yards in length. They are scrolled in juxtaposition and form a hollow cubic cylinder of 8 inches and 9/10 (Fig 1-2)

1˚ if the electric current is passed through one of the wires - in breaking it constantly - one receives strong shocks from the handles of the extra-current AB. But as soon as the ends of the second wire are joined together - the extra-current ceases completely.

2˚ If the ends of the inductive wire B'A are connected with a Voltameter or with an helix formed of a wire of 1/300 of an inch and 500 yards in length - the effects of the extra-current reappear[.]

3˚ On receiving the induced or the extra-current shocks are given. The same effect is produced in grasping the handle ending the Wire A of the extra-current - and the handle ending the Wire B' of the induced current - or the two handles A'B. On the contrary on grasping in the same time AA' or BB' nothing at all is felt[.]

The handles AB' being kept by one person - as soon as the two handles A'B shall be connected - or shall be touched by another person - the shocks become stronger. The same result takes place with two helices of various lengths superposed and distant of 7/10 of an inch (Fig 4)[.]

4˚ Three helices being superposed as it is shewn in the Fig 3 - the first formed of 38 yards of copper wire 1/10 of an inch in diameter - the second of 176 yards of copper wire 1/300 of an inch and the third of 230 yards of the same fine wire - constituting rings of 6 inches in diameter - if broken currents from ten elements pass through the first - the two ends of the second being united - the third is not induced. But as soon as the ending wires of the second ring are connected with a voltameter - or with the helix above described the induction appears and shocks are received.

5˚ The two wires in the helix fig 2. being united so as to form a single one of 1210 yards - if the wires of the extra-current are connected with the conductors of the electrical egg - between the terminal - gold - silver - platina - copper - zinc - iron - charcoal balls - shall appear all the series of phenomena obtained with a powerful electrical machine. The positive ball is always surrounded by a constant violet glow rising some inches along the rod which supports it. From the obscure negative balls - flows a red brush reaching the positive. In using copper balls - red squibs rush out from the negative - ending in brilliant and white stars surrounded by a green glow - connecting the basis of the brush with every point of the surface of the positive ball and rod (Fig. 5). In using platina - if instead of the positive ball - an helix with loose curls - is applied to the rod - the violet glow is more extended and intense. In every case the brush takes place at a distance and without any previous contact[.]

6˚ During the preceding experiments an iron cylinder 50 pounds weight being introduced into the hollow of the helix - the shocks grow suddenly weaker - the light diminishes and sometimes vanishes.

I desire that communication to be agreeable to you. There are some new facts not yet cleared up which I shall [word illegible] to you after renewed experiments[.]

I am Sir | Your most grateful and obedient | servant | Peyron

I have undertaken the translation of your Experimental Researches, the very Code of electricians of which I ambition to endow my own country. I hope that long and difficult task will be completed next year. But before publishing it I shall have the pleasure of submitting my attempt to your approbation[.]

Endorsed by Faraday: Dr. Peyron professor of natural philosophy, Marseilles 18 Rue d'Aguesseau, Paris.