Little Masterpieces of Science: Invention and Discovery
History
Little Masterpieces of Science: Invention and Discovery
Inventions
What was the reason of this failure? Faraday never could work from the
experiments of others, however clearly described. He knew well that from
every experiment issues a kind of radiation, luminous, in different
degrees to different minds, and he hardly trusted himself to reason upon
an experiment that he had not seen. In the autumn of 1831 he began to
repeat the experiments with electric currents, which, up to that time,
had produced no positive result. And here, for the sake of younger
inquirers, if not for the sake of us all, it is worth while 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 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.
Public-domain text, read in full here on John Shaqi.
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