s
simple in their mechanism as they are astonishing in their results,
have been given to a delighted world. Some of Edison's inventions
have a character at present of little more than picturesque
playfulness, such as the Phonograph, perhaps the most remarkable of
these minor inventions; the Aerophone, by which sounds are amplified
without loss of distinctness; the Megaphone, an instrument which,
inserted in the ear, so magnifies sounds that faint whispers may be
heard a thousand feet; the Phonometer, for measuring the force of
the soundwaves caused by the human voice; the Microtasimeter, for
measuring small variations in temperature. This has been tested for
so small a variation as 1/24000 of a degree Fahrenheit, and in 1878
was used to detect the presence of heat in the sun's corona. The
most familiar of these lesser inventions is the Phonograph by which
sounds are made self-recording and capable of being repeated. While
this curious invention--almost childish in its simplicity--is as yet
little more than a plaything, and has proved of small utility, it
makes, nevertheless, a strong appeal to the imagination when we
reflect that by its aid the voice of any human being may be
transmitted to ages far in the future, and its living tones be heard
long after he who uttered them has returned to the dust.

But, while these inventions have the charm that invests "the
fairy-tales of science," the world-wide fame of Edison rests upon
greater gifts to the world; the various improvements he has made in
the telegraph, and the perfection to which he has brought the
electric light. The invention of the telephone, by which persons are
enabled to converse with one another at very long distances, and by
which concerts, operas, and orations or sermons in one city can be
heard by an audience assembled in another, is one of the most
remarkable of Edison's achievements, and one the usefulness of which
in various directions it is easy to foresee. The idea of the
transmission of messages in opposite directions by the same wire was
one that had early occurred to Edison, but he was long in reducing
it to practice. The secret once discovered, however, he rapidly
progressed until he had brought out the sextuple telegraph, where we
believe the ability of the instrument rests at present.

The inventor next turned his mind to the study of the electric lamp,
in which he saw great possibilities. He believed that he could
produce a light that should