John Peter Gassiot to Faraday   28 May 1855

Clapham Common | 28 May 1855

My Dear Faraday

During the progress of your lecture last Friday Evening¹ it occurred to me that the question you had raised as to conduction proper might be explained by some experiments I made a few years since & which are described in a paper published in the RS. transactions (PT 1844)² - it appears to my mind to explain that peculiar action which arises in a Voltaic Battery when it is thrown into a state of tension before actual Electrolysis takes place, and that this is similar to the induced state of an Electrified Body previous to its receiving the actual discharge from the Electrical Machine[.]

I will briefly describe the Experiment - Charge in the usual manner (taking care to keep the outer portion of each cell dry) a number of cells or series of a Voltaic Battery sufficient to diverge the leaves of Gold leaf Electroscopes - one of which is attached to the + and the other to the - terminal, introduce into the circuit a delicate Galvanometer and two platinum wires the ends of which rest on a piece of bibulous paper saturated with a solution of Iodide of Potassium (as in original Experiment) - the Battery and entire apparatus being insulated - in this state the leaves of the Electroscopes will diverge one with + and the other with - Electricity. When all is thus arranged touch with a wire or with the finger - either terminal, the leaves of the electroscope will collapse, while those of the instrument attached to the other terminal will diverge with increased intensity - repeat this by touching first one and then the other terminal, the alternating and progressive effect shews some action must be passing through the entire Battery, but the needle of the Galvanometer (let the instrument be ever so delicate) is not deflected nor is there the slightest trace of Chemical action in the solution of Iodide of Potassium[.]

If as in my water Battery the terminals are brought sufficiently near to allow a spark to pass, or let the circuit be completed for a moment of time the deflection of the needle takes place & Iodine is evolved.

Have we not in this conduction proper through the battery without Chemical action[.]

Believe me | My Dear Faraday | Yours truly | John P. Gassiot

My Dear Faraday

I met Tyndall on Saturday³ talking over with him the subject of yr lecture he appeared to me to think the Solution might be as I have represented - if you think th<<is>> worth inserting you may send it to the P.M., if I am wrong put it into fire[.]

Excuse this scrawl & the paper but I am off to Mark Lane⁴ & have nothing else to write on[.]

Believe me | Yours | J.P. Gassiot

Monday Morning

Address: Dr. Faraday | Royal Institution | Albermarle Street