162 Scientific Proceedings, Royal Dublin Society. 
through the discoveries of Helmholtz and the investigations of 
Léon, Scott, Konig, and others. 
The vibratory action in the Logograph appears to depend 
mainly on the pitch of the fundamental note, and to be but little 
aftected by those harmonics and their compounds which have 
been shown by Helmholtz to govern the differences in vowel 
sounds. 
If the gamut be sung into the mouth-piece, although more 
than one note will produce vibration, yet its greatest develop- 
ment is found at some one note, which may be assumed that 
corresponding with the vibration rate of the membrane in its then 
state of tension; and the best exhibition of vowel action is 
obtained by speaking in a monotone upon such note when dis- 
covered by trial. 
The diphthongs appear to indicate some check in the action 
when the sound changes ; but it is difficult to determine. 
The long, simple vowel sounds, used in English, which can be 
made without any alteration of the organs during their action, 
appear to be— 
00 (as in COO), 0, ad, ee, ev, ah, awe. 
The three latter are not generally given as vowels, but they 
appear to be so. 
The sound of er is that heard in the French de, ce, que, &e. 
The French also use two vowel sounds, ew and ewr, not found in 
English. The sound of the French eur is given by Max Miiller 
as a diphthong. 
In addition to the simple long vowels, we have the diphthongs 
formed by their combinations, and another series derived from 
pronouncing the vowel sounds short, as in pit, pat, pet, &e. 
Besides the great variety thus produced in vowel sounds, 
there appears also to be the fundamental note itself. The sound 
referred to is that heard between the syllables 
el—tlee, 
in which case it comes from the mouth, and 
em—me, 
in which it comes from the nose. 
It is heard when words are spoken by people at such a distance 
that the fact, only, of conversation is sensible to the ear, the articu- 
