To an ever-increasing, quite uncontrolled degree - for to the mind of
present-day man it is only natural to translate every new discovery
into practice as soon and as extensively as possible - electricity
enters decisively into our modern existence. If we take all its
activities into account, we see arising amongst humanity a vast realm
of labour units, possessed in their own way not only of will but of the
sharpest imaginable intelligence. Although they are wholly remote from
man's own nature, he more and more subdues his thoughts and actions to
theirs, allowing them to take rank as guides and shapers of his
civilization.

Turning to the sphere of scientific research, we find electricity
playing a role in the development of modern thinking remarkably similar
to its part as a labour-force in everyday life. We find it associated
with phenomena which, in Professor Heisenberg's words, expose their
mutual connexions to exact mathematical thinking more readily than do
any other facts of nature; and yet the way in which these phenomena
have become known has played fast and loose with mathematical thinking
to an unparalleled degree. To recognize that in this sphere modern
science owes its triumphs to a strange and often paradoxical mixture of
outer accident and error in human thought, we need only review the
history of the subject without prejudice.

*

The discovery of electricity has so far been accomplished in four
clearly distinct stages. The first extends from the time when men first
knew of electrical phenomena to the beginning of the natural scientific
age; the second includes the seventeenth and the greater part of the
eighteenth centuries; the third begins with Galvani's discovery and