le to dwell for
a moment on a power which Faraday possessed in an extraordinary degree.
He united vast strength with perfect flexibility. His momentum was that
of a river, which combines weight and directness with the ability to
yield to the flexures of its bed. The intentness of his vision 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 preoccupation.

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 10 cells to 120
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 dir