rds, it was at Geneva in company with M.A. De la Rive: the latter
philosopher described the results[A], and says that the plate of copper
bent into a circle which was used as the mobile conductor "sometimes
advanced between the two branches of the (horse-shoe) magnet, and sometimes
was repelled, _according_ to the direction of the current in the
surrounding conductors."

[A] Bibliotheque Universelle, xxi. p. 48.

I have been in the habit of referring to Demonferrand's _Manuel
d'Electricite Dynamique_, as a book of authority in France; containing the
general results and laws of this branch of science, up to the time of its
publication, in a well arranged form. At p. 173, the author, when
describing this experiment, says, "The mobile circle turns to take a
position of equilibrium as a conductor would do in which the current moved
in the _same direction_ as in the spiral;" and in the same paragraph he
adds, "It is therefore proved _that a current of electricity tends to put
the electricity of conductors, near which it passes, in motion in the same
direction._" These are the words I quoted in my paper (78.).

Le Lycee of 1st of January, 1832, No. 36, in an article written after the
receipt of my first unfortunate letter to M. Hachette, and before my papers
were printed, reasons upon the direction of the induced currents, and says,
that there ought to be "an elementary current produced in the same
direction as the corresponding portion of the producing current." A little
further on it says, "therefore we ought to obtain currents, moving in the
_same direction_, produced upon a metallic wire, either by a magnet or a
current. M. Ampere _was so thouroughly persuaded that such ought to be the
direction of the currents by influence_, that he neglected to assure
himself of it in his experiment at Geneva."

It was the precise statements in Demonferrand's Manuel, agreeing as they
did with the expression in M. De la Rive's paper, (which, however, I now
understand as only meaning that when the inducing current was changed, the
motion of the mobile circle changed also,) and not in discordance with
anything expressed by M. Ampere himself where he speaks of the experiment,
which made me conclude, when I wrote the paper, that what I wrote was
really his avowed opinion; and when the Number of the Lycee referred to
appeared, which was before my paper was printed, it could excite no
suspicion that I was in error.

Hence the mistake int