London
20 Feb. 1834
My Dear Mr F.
I saw today at Watkins’s <1> a very curious machine, <2> invented chiefly by Faraday <3> but improved by various other persons, by which you obtain from a common Magnet not only sparks, but very strong shocks almost as much as the hand can endure, in rapid succession so as almost to be continual; and moreover by the same apparatus you decompose water, resolving it into a mixture of oxygen & hydrogen gas, which you may afterwards unite again by applying a lighted candle when they unite with an explosion as usual. These effects are obtained by merely whirling round the keeper of a common Magnet that is the bar of iron which unites its poles, together with a certain arrangement of coils of wire &c. The remarkable thing is that these effects are obtained without the expenditure of any fuel or of any acid, or anything else, so long as you continue to rotate the magnet, whereas a galvanic battery ceases its action in half an hour unless you supply new acid & (after some months service) new copper & zinc plates. Whereas this machine requires nothing but a moving power, as for instance a waterwheel.
Your affte
Henry
Captn Feilding
Notes:
1. Francis Watkins, of Watkins & Hill, instrument makers, London.
2. Dynamo, electric generator.
3. Prof Michael Faraday (1791–1867), scientist.