It was the last link of a long chain of discoveries.
It was the result of a persistent and
deliberate search. Already, for half a year
or longer, Bell had known the correct theory of
the telephone; but he had not realized that the
feeble undulatory current generated by a magnet
was strong enough for the transmission of speech.
He had been taught to undervalue the incredible
efficiency of electricity.

Not only was Bell himself a teacher of the
laws of speech, so highly skilled that he was
an instructor in Boston University. His father,
also, his two brothers, his uncle, and his
grandfather had taught the laws of speech in the
universities of Edinburgh, Dublin, and London.
For three generations the Bells had been professors
of the science of talking. They had even
helped to create that science by several inven-
tions. The first of them, Alexander Bell, had
invented a system for the correction of stammering
and similar defects of speech. The second,
Alexander Melville Bell, was the dean of British
elocutionists, a man of creative brain and a most
impressive facility of rhetoric. He was the author
of a dozen text-books on the art of speaking
correctly, and also of a most ingenious
sign-language which he called "Visible Speech."
Every letter in the alphabet of this language
represented a certain action of the lips and