down in the indentations and through the figures
in the tin-foil, produced by its own previous agitation, a quiver
exactly equivalent to that which was produced by the utterance in the
mouth-piece is thrown into the air. This agitation is of course the
exact physical equivalent of the original sound, or, more properly,
_is_ the sound itself. Thus it is that the phonograph is made to talk,
to sing, to cry; to utter, in short, any sound sufficiently powerful
to produce a perceptible tremor in the mouth-piece and diaphragm of
the instrument.

Much progress has been made toward the utilization of the phonograph
as a practical addition to the civilizing apparatus of our time. It
may be said, indeed, that all the difficulties in the way of such a
result have been removed. Mr. Edison has carried forward his work to
such a degree of perfection that the instrument may be practically
employed in correspondence and literary composition. The problem has
been to _stereotype_, so to speak, the tin-foil record of what has
been uttered in the mouth-piece, and thus to preserve in a permanent
form the potency of vanished sounds. Nor does it require a great
stretch of the imagination to see in the invention of the phonograph
one of the greatest achievements of the age--a discovery, indeed,
which may possibly revolutionize the whole method of learning.

It would seem clear that nature has intended the _ear_, rather than
the eye, to be the organ of education. It is manifestly against the
fitness of things that the eyes of all mankind should be strained,
weakened, permanently injured in childhood, with the unnatural tasks
which are imposed upon the delicate organ. It would seem to be more in
accordance with the nature and capacities of man, and the general
character of the external world, to reserve the eye for the
discernment and appreciation of beauty, and to impose upon the ear
the tedious and hard tasks of education.

The phonograph makes it possible to read by the ear instead of by the
eye, and it is not beyond the range of probability that the book of
the future, near or remote, will be written in phonographic plates and
made to reveal its story directly to the waiting ear, rather than
through the secondary medium of print to the enfeebled and tired eye
of the reader.

We hardly venture on prophecy; but we think that he who returns to
this scene of human activity at the close of the twentieth century
will find that sound has been