derable
degree, by the introduction of silica.'

[5] Regarding Anderson, Faraday writes thus in 1845:--'I
cannot resist the occasion that is thus offered to me of
mentioning the name of Mr. Anderson, who came to me as an
assistant in the glass experiments, and has remained ever
since in the laboratory of the Royal Institution. He
assisted me in all the researches into which I have entered
since that time; and to his care, steadiness, exactitude,
and faithfulness in the performance of all that has been
committed to his charge, I am much indebted.--M. F.' (Exp.
Researches, vol. iii. p. 3, footnote.)

Chapter 3.

Discovery of Magneto-electricity: Explanation of Argo's
magnetism of rotation: Terrestrial magneto-electric
induction: The extra current.

The work thus referred to, though sufficient of itself to secure no
mean scientific reputation, forms but the vestibule of Faraday's
achievements. He had been engaged within these walls for eighteen years.
During part of the time he had drunk in knowledge from Davy, and during
the remainder he continually exercised his capacity for independent
inquiry. In 1831 we have him at the climax of his intellectual strength,
forty years of age, stored with knowledge and full of original power.
Through reading, lecturing, and experimenting, he had become thoroughly
familiar with electrical science: he saw where light was needed and
expansion possible. The phenomena of ordinary electric induction
belonged, as it were, to the alphabet of his knowledge: he knew that
under ordinary circumstances the presence of an electrified body was
sufficient to excite, by induction, an unelectrified body. He knew that
the wire which carried an electric current was an electrified body, and
still that all attempts had failed to make it excite in other wires a
state similar to its own.

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 whi