Faraday to William Henry Adcock   25 April 1856¹

R Institution, | 25 April 1856.

Sir,

The above is a copy of your drawing with the addition of two arrow heads shewing the course of the electric current in the upper part of ab. Now it is manifest that the current in the upper part a is contrary in direction to that in the lower part b, and therefore a will tend to move in one direction and b in the contrary direction. If a and b be far apart then a concentrated pole near b may move the whole in one direction uncertainly upon occasions, but the form of ab is unfitted to shew the Electro-magnetic motions - that mere helices can move wires carrying currents has been shown long ago by either Ampere² or Arago or both³.

Your Obedient Servant, | (signed) M. Faraday

Address: Mr W.N. [sic] Adcock, The Mills, Ashby de la Zouch, Leicestershire