88 
Proceedings of Royal Society of Edinburgh. 
SESS. 
On the Derivation of the Curves of Vowel Sounds by 
means of Microscopical Research of their Phono- 
grams. By J. D. Boeke, Alkmaar, Holland. ( Presented 
by Professor M‘Kendrick.) 
(Read February 7, 1898.) 
For about seven years I have been engaged upon the investiga- 
tion of the impressions made by vowel sounds on phonograph 
cylinders. 
The close accordance of my results with those of Prof. L. Her- 
mann of Konigsberg * and Dr Hugo Pipping of Helsingfors,! though 
obtained by widely different methods, showed, 1st, that the method 
by which I obtained my results, although much simpler and easier 
to manage than those of the above-mentioned investigators, yields, 
nevertheless, very satisfactory results; and 2nd, that the same 
vowel sounds are formed almost exactly in the same manner by 
persons of different age, sex, and nationality. 
In the only scientific paper which, till now, I have published on 
this subject,| i n 1891, only the vowel a (as in hard) was treated in 
a somewhat elaborate manner, but since then I have applied my 
method to other vowels as well. 
As I have altered my method of research a little in the course 
of time, it may be useful to give a somewhat detailed description 
of my present mode of procedure. 
It consists in measuring, microscopically, the transverse diameter 
of the impressions on the surface of the phonograph cylinder on 
different (generally equidistant) parts of the period, and in inferring 
from my measurements the depth of the impression on the same 
* L. Hermann, “ Phonophotografische Untersuchunge,” Pfiiiger's Archiv., 
45, p. 582 ; 47, pp. 42, 47 ; 53, p. 1 ; 58, p. 255 ; 61, p. 169. 
t H. Pipping, “ Zur Lehre von d. Vocal Kl.,” Zeitschr. fur Biologie, 27 
N.F. Bdg., p. 1 ; 9, 524; “Ueber die theorie der Vocale,” Acta Societatis 
Scientiorum fennicce , T. xx. No. 11. 
X J. D. Boeke, “Mikroskopische Phonogramm-Studien,” Pfiiiger’s Archiv ., 
Bd. 50, p. 297. 
