On the Articulution of the Human Voree, 161 
DOUBLE RE-ACTION. 
When a syllable terminates with a compound formed of two 
hard, or percussive, consonants, there is a double re-action—as, for 
example, in the words 
apt, helped, 
Bema AS PS lw ke ee 
Fhe: Te 
abrupt. 
pea gp al ola Sa 
In these and similar cases it is obvious that the vowel action 
must terminate in the negative action of the first consonant, 
which in these examples is p ; and the presence of the ¢ or d is only 
made known by the re-action, which is without any vowel 
sound. 
In some French words, such as étre, métre, &c., the silent re- 
action is very strongly developed; probably from the force necessary 
to produce the consonantal compounds in such words. In these 
and many similar cases the re-action assumes the form of a 
whispered syllable. 
These re-actions without vowel sound give rise to the con- 
sideration that the sensation of percussion operates independently 
of any vowel sound, and that we know what is spoken, not only 
by vowel sounds and the manner in which these sounds are 
begun and ended, but also by the pneumatic percussions or 
pressures which accompany them, and which, though not heard 
may be felt. 
etre, etre, metre. metre. 
= e Aa He 
et. et. meet. met, 
VOWEL SOUNDS. 
All the vowel sounds produce a vibratory action on the mem- 
brane of the Logograph sufficient to show the duration of the 
sound and its position in the diagram; but the scale of the 
diagram is too small, and the arrangement of the instrument is 
~ not adapted, to show those changes which distinguish one vowel 
sound from another, with which we are already acquainted, 
