of Edinburgh, Session 1877-78. 
725 
In order, however, to test this still further, we made the following 
experiment. A tube consisting of a piece of cane of the same size 
as one of the reeds was put into the neck of the bottle in place of 
the reed, and the side apertures of the bottle were closed so as to 
arrange the cavity for the vowel sound 0. The end of the tube was 
then inserted in the ear, so that the whole apparatus acted as a 
resonator to sounds from outside. Then, striking the keys of a 
piano in succession, we observed what notes gave the peculiar 
humming effect due to reinforcement by the resonator. On working 
down the scale the resonance first became appreciable on gjfc'. It 
then got stronger and stronger down to f" and e ", which were both 
intensely and nearly equally strong. e\>" and d" were a little weaker, 
but still very strong, and on cty' the resonance again became very 
intense, c" was a little weaker, but also very strong. The reson- 
ance continued as the pitch fell, being sometimes stronger and 
sometimes weaker, g and /$' were both strong, — decidedly stronger 
than could be accounted for by the reinforcement of their second 
partials g" and /J". f was weaker, — so much so that the resonance 
observed on it might be due to the second partial. 
The presence of the upper partials in the notes struck made this 
method of testing the resonant qualities of the cavity inapplicable 
to pitches below those named. But the above cases, in which the 
reinforcement was distinctly of the prime, sufficed to show that the 
cavity would strengthen any tones between gfy" and fjf/, at least, 
some more and some less strongly, while they left it an open ques- 
tion whether there was not resonance down to a lower limit of abso- 
lute pitch. Of course, it is to be observed that the bottle, when 
applied to the ear in the manner described, might differ in its 
resonant peculiarities from the same bottle applied to a reed, but its 
range is probably as great in the former case. 
When the bottle was arranged for the vowel sound A, and tested 
in the same way, the resonance was perceptible as high as e'", and 
the highest maximum occurred on c'". In this case also there was 
reinforcement over a range of at least an octave. 
Traces of the wave forms of the artificial O’s spoken of in this 
paper will be given along with those of other O’s when the full 
account of our work is printed. 
5 c 
VOL. IX. 
