the great mass of scientific facts revealed
in the laboratory. In the course of time, however, the nature of the
new fact began to be apprehended. The electric lamp in many forms was
proposed and tried. The scientists, Niardet, Wilde, Brush, Fuller, and
many others of less note, busied themselves with the work of
invention. Especially did Gramme and Siemens devote their scientific
genius to the work of turning to good account the knowledge now fully
possessed of the transformability of the electric current into light.

The experiments of the last named two distinguished inventors brought
us to the dawn of the new era in artificial lighting. The Russian
philosopher, Jablokhkoff, carried the work still further by the
practical introduction of the carbon candle. Other scientists--Carre,
Foucault, Serrin, Rapieff, and Werdermann--had, at an earlier or later
day, thrown much additional information into the common stock of
knowledge relative to the illuminating possibilities of electricity.
Finally, the accumulated materials of science fell into the hands of
that untutored but remarkably radical inventor, Thomas A. Edison, who
gave himself with the utmost zeal to the work of removing the
remaining difficulties in the problem.

Edison began his investigations in this line of invention in September
of 1878, and in December of the following year gave to the public his
first formal statement of results. After many experiments with
platinum, he abandoned that material in favor of the carbon-arc _in
vacuo_. The latter is, indeed, the essential feature of the Edison
light. A small semicircle, or horseshoe, of some substance, such as a
filament of bamboo reduced to the form of pure carbon, the two ends
being attached to the poles of the generating-machine, or dynamo, as
the engine is popularly called, is enclosed in a glass bulb, from
which the air has been carefully drawn, and is rendered incandescent
by the passage of an electric current. The other important features of
Edison's discovery relate to the divisibility of the current, and its
control and regulation in volume by the operator. These matters were
fully mastered in the Edison invention, and the apparatus rendered as
completely subject to management as are the other varieties of
illuminating agencies.

It were vain to speculate upon the future of electric lighting. The
question of artificial illumination has had much to do with the
progress of the human race, particular