|Bell had been studying new methods to improve the telegraphic
transmissions. However, during his spare time it was devoted
to develop techniques for teaching deaf people to speak and
to read lips.
During his research work he had studied several voice-actuated
instruments, like the Koenig manometric capsule as well as
the Phonoutograph invented by Martinville.
While conducting these experiments, Bell was struck by the
similarity of the Phonautograph to the human ear. In this
way he concluded that a similar apparatus modeled after the
structure of the human ear probably could produce more acurate
register of the speech vibrations.
Since Bell had any knowledge on reproducing the structure
of the human ear he called on the acquaitance of Dr. Clarence
J. Blake, a famous American otologist, who advised him to
start a meticulous study of human ear anatomy from a dead
man available from the morgue of Harvard Medical School.
In mid 1874, Bell carried on several experiments in such way
when speaking into the anatomical piece coupled to a Phonautograph,
it made tracings of the speech vibrations over a piece of
Considering those early fundamental experiments for the future
development of the telephone, Bell begun to develop the transmission
of the spoken words on wires through the use of the harmonic