esired, was solved.' [T. A.
Edison, NORTH AMERICAN REVIEW, June, 1888; New York ELECTRICAL REVIEW,
1888,]

The experiment shows that it was partly by accident, and not by
reasoning on theoretical knowledge, that the phonograph was discovered.
The sound resembling 'human talk heard indistinctly' seems to have
suggested it to his mind. This was the germ which fell upon the soil
prepared for it. Edison's thoughts had been dwelling on the telephone;
he knew that a metal tympanum was capable of vibrating with all the
delicacies of speech, and it occurred to him that if these vibrations
could be impressed on a yielding material, as the Morse signals were
embossed upon the paper, the indentations would reproduce the speech,
just as the furrows of the paper reproduced the Morse signals. The
tympanum vibrating in the curves of speech was instantly united in
his imagination with the embossing stylus and the long and short
indentations on the Morse paper; the idea of the phonograph flashed upon
him. Many a one versed in acoustics would probably have been restrained
by the practical difficulty of impressing the vibrations on a yielding
material, and making them react upon the reproducing tympanum. But
Edison, with that daring mastery over matter which is a characteristic
of his mechanical genius, put it confidently to the test.

Soon after this experiment, a phonograph was constructed, in which a
sheet of tinfoil was wrapped round a revolving barrel having a spiral
groove cut in its surface to allow the point of the indenting stylus
to sink into the yielding foil as it was thrust up and down by the
vibrating tympanum. This apparatus--the first phonograph--was published
to the world in 1878, and created a universal sensation. [SCIENTIFIC
AMERICAN, March 30, 1878] It is now in the South Kensington Museum, to
which it was presented by the inventor.

The phonograph was first publicly exhibited in England at a meeting of
the Society of Telegraph Engineers, where its performances filled the
audience with astonishment and delight. A greeting from Edison to
his electrical brethren across the Atlantic had been impressed on the
tinfoil, and was spoken by the machine. Needless to say, the voice of
the inventor, however imperfectly reproduced, was hailed with great
enthusiasm, which those who witnessed will long remember. In this
machine, the barrel was fitted with a crank, and rotated by handle. A
heavy flywheel was attached to give it uni