.

Summary.

When from an Alpine height the eye of the climber ranges over the
mountains, he finds that for the most part they resolve themselves into
distinct groups, each consisting of a dominant mass surrounded by peaks
of lesser elevation. The power which lifted the mightier eminences, in
nearly all cases lifted others to an almost equal height. And so it is
with the discoveries of Faraday. As a general rule, the dominant result
does not stand alone, but forms the culminating point of a vast and
varied mass of inquiry. In this way, round about his great discovery of
Magneto-electric Induction, other weighty labours group themselves. His
investigations on the Extra Current; on the Polar and other Condition of
Diamagnetic Bodies; on Lines of Magnetic Force, their definite character
and distribution; on the employment of the Induced Magneto-electric
Current as a measure and test of Magnetic Action; on the Revulsive
Phenomena of the magnetic field, are all, notwithstanding the diversity
of title, researches in the domain of Magneto-electric Induction.

Faraday's second group of researches and discoveries embrace the
chemical phenomena of the current. The dominant result here is the great
law of definite Electro-chemical Decomposition, around which are massed
various researches on Electro-chemical Conduction and on Electrolysis
both with the Machine and with the Pile. To this group also belongs
his analysis of the Contact Theory, his inquiries as to the Source of
Voltaic Electricity, and his final development of the Chemical Theory of
the pile.

His third great discovery is the Magnetization of Light, which I should
liken to the Weisshorn among mountains--high, beautiful, and alone.

The dominant result of his fourth group of researches is the discovery
of Diamagnetism, announced in his memoir as the Magnetic Condition of
all Matter, round which are grouped his inquiries on the Magnetism
of Flame and Gases; on Magne-crystallic action, and on Atmospheric
Magnetism, in its relations to the annual and diurnal variation of the
needle, the full significance of which is still to be shown.

These are Faraday's most massive discoveries, and upon them his fame
must mainly rest. But even without them, sufficient would remain to
secure for him a high and lasting scientific reputation. We should
still have his researches on the Liquefaction of Gases; on Frictional
Electricity; on the Electricity of the Gymnotus; on the so