positions of the vocal organs in forming sounds. Together we
carried on quite a number of experiments, seeking to discover the
correct mechanism of English and foreign elements of speech, and I
remember especially an investigation in which we were engaged
concerning the musical relations of vowel sounds. When vocal sounds are
whispered, each vowel seems to possess a particular pitch of its own,
and by whispering certain vowels in succession a musical scale can be
distinctly perceived. Our aim was to determine the natural pitch of each
vowel; but unexpected difficulties made their appearance, for many of
the vowels seemed to possess a double pitch--one due, probably, to the
resonance of the air in the mouth, and the other to the resonance of the
air contained in the cavity behind the tongue, comprehending the pharynx
and larynx.

I hit upon an expedient for determining the pitch, which, at that time,
I thought to be original with myself. It consisted in vibrating a tuning
fork in front of the mouth while the positions of the vocal organs for
the various vowels were silently taken. It was found that each vowel
position caused the reinforcement of some particular fork or forks.

I wrote an account of these researches to Mr. Alex. J. Ellis, of London.
In reply, he informed me that the experiments related had already been
performed by Helmholtz, and in a much more perfect manner than I had
done. Indeed, he said that Helmholtz had not only analyzed the vowel
sounds into their constituent musical elements, but had actually
performed the synthesis of them.

He had succeeded in producing, artificially, certain of the vowel sounds
by causing tuning forks of different pitch to vibrate simultaneously by
means of an electric current. Mr. Ellis was kind enough to grant me an
interview for the purpose of explaining the apparatus employed by
Helmholtz in producing these extraordinary effects, and I spent the
greater part of a delightful day with him in investigating the subject.
At that time, however, I was too slightly acquainted with the laws of
electricity fully to understand the explanations given; but the
interview had the effect of arousing my interest in the subjects of
sound and electricity, and I did not rest until I had obtained
possession of a copy of Helmholtz's great work "The Theory of Tone," and
had attempted, in a crude and imperfect manner, it is true, to reproduce
his results. While reflecting upon the possibilitie