1897-98.] Dr Lloyd on Analysis of Tracings of Vowels. 
97 
On the Fourierian Analysis of Phonographic Tracings 
of Vowels, By R. J. Lloyd, Doc. Lit., etc., Liverpool. 
(Read February 7, 1898. ) 
It is a great advantage and satisfaction to work from curves 
taken by the phonograph itself, because it is then possible to repro- 
duce and verify by actual hearing the sound supposed to be repre- 
sented by given curves. This ought always to be done, even with 
the phonograph, and the slightest change of timbre should be care- 
fully noted ; for the given curve represents not really the original 
sound, but the sound given back by the phonograph. Every plate 
or membrane vibrates more readily and strongly to some pitches 
than to others, and in a composite sound it is almost inevitable 
that some of its elements are recorded with more, and others with 
less, than their original relative force. Different vibrators hence 
yield quite different-looking phonograms for the same sound. In 
vowels it seems fortunately to happen that considerable changes in 
the relative force of the component vibrations may occur without 
altering the vowel. It is the pitch of the components which 
matters ; and that is not altered by an efficient vibrator. Assum- 
ing a knowledge of the methods by which the record dug ver- 
tically into the phonographic cylinder is displayed horizontally for 
examination and analysis, we note that a satisfactory Fourierian 
analysis demands a sufficient number of measurements. A single 
wave is taken ( AA, BB, fig. ] ), and referred to rectangular axes 
OX, OY. Abscissae of equal length are measured off along OX, 
and ordinates are drawn to meet the curve, and are very accurately 
measured. Eor a simple curve like A A a few ordinates suffice, but 
if the curve is complex, the number of measurements must be 
increased until no considerable curvature exists between the sum- 
mits of any two successive ordinates. It can be seen at a glance 
that the curve BB, with twice the number of ordinates possessed 
by AA, is insufficiently registered. When a sufficient number of 
YOL. XXII. 26/3/98. G 
