sion in any
direction did not apparently diminish his power of perception in other
directions; and when he attacked a subject, expecting results, he had
the faculty of keeping his mind alert, so that results different from
those which he expected should not escape him through pre-occupation.
He began his experiments "on the induction of electric currents" by
composing a helix of two insulated wires, which were wound side by side
round the same wooden cylinder. One of these wires he connected with a
voltaic battery of ten cells, and the other with a sensitive
galvanometer. When connection with the battery was made, and while the
current flowed, no effect whatever was observed at the galvanometer.
But he never accepted an experimental result, until he had applied to
it the utmost power at his command. He raised his battery from ten cells
to one hundred and twenty cells, but without avail. The current flowed
calmly through the battery wire without producing, during its flow, any
sensible result upon the galvanometer.
"During its flow," and this was the time when an effect was
expected--but here Faraday's power of lateral vision, separating, as it
were from the line of expectation, came into play--he noticed that a
feeble movement of the needle always occurred at the moment when he made
contact with the battery; that the needle would afterwards return to its
former position and remain quietly there unaffected by the _flowing_
current. At the moment, however, when the circuit was interrupted the
needle again moved, and in a direction opposed to that observed on the
completion of the circuit.
This result, and others of a similar kind, led him to the conclusion
"that the battery current through the one wire did in reality induce a
similar current through the other; but that it continued for an instant
only, and partook more of the nature of the electric wave from a common
Leyden jar than of the current from a voltaic battery." The momentary
currents thus generated were called _induced currents_, while the
current which generated them was called the _inducing_ current. It was
immediately proved that the current generated at making the circuit was
always opposed in direction to its generator, while that developed on
the rupture of the circuit coincided in direction with the inducing
current. It appeared as if the current on its first rush through the
primary wire sought a purchase in the secondary one, and, by a kind of
ki
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