tors near which it passes
in motion in the same direction," for they indicate an opposite direction
for the produced current (26. 53.); and they show that the effect is
momentary, and that it is also produced by magnetic induction, and that
certain other extraordinary effects follow thereupon.

79. The momentary existence of the phenomena of induction now described is
sufficient to furnish abundant reasons for the uncertainty or failure of
the experiments, hitherto made to obtain electricity from magnets, or to
effect chemical decomposition or arrangement by their means[A].

[A] The Lycee, No. 36, for January 1st, has a long and rather
premature article, in which it endeavours to show anticipations by
French philosophers of my researches. It however mistakes the
erroneous results of MM. Fresnel and Ampere for true ones, and then
imagines my true results are like those erroneous ones. I notice it
here, however, for the purpose of doing honour to Fresnel in a much
higher degree than would have been merited by a feeble anticipation of
the present investigations. That great philosopher, at the same time
with myself and fifty other persons, made experiments which the
present paper proves could give no expected result. He was deceived
for the moment, and published his imaginary success; but on more
carefully repeating his trials, he could find no proof of their
accuracy; and, in the high and pure philosophic desire to remove error
as well as discover truth, he recanted his first statement. The
example of Berzelius regarding the first Thorina is another instance
of this fine feeling; and as occasions are not rare, it would be to
the dignity of science if such examples were more frequently
followed.--February 10th, 1832.

80. It also appears capable of explaining fully the remarkable phenomena
observed by M. Arago between metals and magnets when neither are moving
(120.), as well as most of the results obtained by Sir John Herschel,
Messrs. Babbage, Harris, and others, in repeating his experiments;
accounting at the same time perfectly for what at first appeared
inexplicable; namely, the non-action of the same metals and magnets when at
rest. These results, which also afford the readiest means of obtaining
electricity from magnetism, I shall now proceed to describe.

S 4. _Explication of Arago's Magnetic Phenomena._

81. If a plate of copper be revolved close to a magnetic needle, or