ly when aggregated into cities.
Doubtless the old systems of lighting are destined in time to give
place altogether to the splendors of the electric glow. The general
effect of the change upon society must be as marked as it is salutary.
Darkness, the enemy of good government and morality in great cities,
will, in great measure, be dispelled by the beneficent agent, over
which the genius of Davy, Gramme, Brush, Edison, and a host of other
explorers in the new continents of science has so completely
triumphed. The ease, happiness, comfort, and welfare of mankind must
be vastly multiplied, and the future must be reminded, in the glow
that dispels the night, of that splendid fact that the progress of
civilization depends, in a large measure, upon a knowledge of Nature's
laws, and the diffusion of that knowledge among the people.

THE TELEPHONE.

Perhaps no other great invention of man has been within so short a
period so widely distributed as the telephone. The use of the
instrument is already co-extensive with civilization. The cost at
which the instruments are furnished is still so considerable that the
poor of the world are not able to avail themselves of the invention;
but in the so-called upper circles of society the use of the telephone
is virtually universal. It has made its way from the city to the town,
from the town to the village, from the village to the hamlet, and even
to the country-side where the millions dwell.

The telephone came by a speedy revelation. It was born of that intense
scientific activity which is the peculiarity of our age. The
antecedent knowledge out of which it sprang had existed in various
forms for a long time. The laws of acoustics were among the first to
be investigated after a true physical science began to be taught. The
phenomena of sound are so universal and experimentation in sound
production so easy, that the governing laws were readily discovered.

Acoustics, we think, foreran somewhat the science of heat, as the
science of heat preceded that of light. Electricity came last. The
telephone is an instrument belonging not wholly, not chiefly, but only
in part, to acoustics. It owes its existence to magnetic induction and
electrical transmission as much as to the mere action of sound. One
foot of the instrument, so to speak, is acoustics, and the other foot
electricity. The telephone philosophically considered is an instrument
for the conversion of a sound-wave into electrical