80 Proceedings of Royal Society of Edinburgh. [sess. 
the resonance cavity for a vowel sound has an absolute pitch, it 
may have a certain effect in reinforcing other subordinate tones or 
partials. While experimentally it may he shown that a constant 
cavity may produce a vowel-like tone, say o, over a wide range of 
pitch, it is probable that the resonant cavities of the human being 
are slightly adjustable, so as to be, as it were, tuned to the pitch 
on which the vowel is sung. In other words, Fleeming Jenkin 
and Ewing hold that both the relative and the absolute factors 
enter into the composition of a vowel, a conclusion not far from 
the truth. 
The subject was taken up by Hermann * about 1890, and he used 
the much improved wax-cylinder phonograph. He succeeded in 
obtaining photographs of the curves on the wax cylinder, a beam 
of light reflected from a small mirror attached to the vibrating 
disk of the phonograph being allowed to fall on a sensitive plate, 
while the phonograph was slowly travelling. The curves thus 
obtained, representing the wave-forms of the vowel-tones, were 
very beautiful. They were submitted to analysis, with the view 
of estimating the pitch of the mean partial or the “formant,” as 
it is called by Hermann, according to the method described in Dr 
Lloyd’s paper already referred to. Hermann also pointed out that 
the quality of a vowel-tone varies considerably, according to the 
rate at which the cylinder was rotated. This should obviously be 
not the case were the relative pitch theory correct. It is curious 
that, even with competent observers, there should be such difficulty 
in deciding this apparently simple question of fact, some asserting 
that there is no difference in quality, and others as positively 
stating that there is a difference when the cylinder is caused to 
move slowly. After many experiments, I have come to the con- 
clusion that there is a difference but not so great as to disguise the 
quality of the vowel. The ear can always distinguish o, or a, or e 
at different rates, but the quality is undoubtedly altered. The 
sound of a vowel never passes, in my judgment, into the sound of 
another vowel. Professor Hermann maintains the reverse. 
Hermann presents the fixed pitch theory in a modified form, 
and states that there is for each vowel a characteristic tone — a 
formant. The pitch of the formant, however, may vary consider- 
* Hermann, op. cit. 
