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the organs of the voice and articulation as near as can be made 
in the ordinary materials at the service of the instrument maker 
-ig desirable. The author found the metallic free reeds as they 
are called, with sheet brass tongues fixed at one end, and vi- 
brating freely in rectangular apertures cut in sheet brass plates, 
to be the most available substitutes for the chorde vocales 
(thyro-arytenoid ligaments) of the human larynx, and india- 
rubber hollow spheres the best representation of the human 
mouth, as resonant cavities. The reeds being fitted by short 
tubes to apertures cut in the hollow spheres to represent the 
fauces of the posterior part of the mouth, and opposite apertures 
‘to represent the opening of the lips being cut, the vowel-sounds 
are produced by compressing the india-rubber shell when blow- 
ing through the reed, to make the shell take the same form as 
‘the mouth when producing a like sound. . pak 
In this manner the vowel-sounds of I (i) as in the word pipe, 
of E (e) as in peep, of A (a) as in papa, of O (0) as in pope and 
of U (u) as (00) in poop, are readily obtained, and shew the 
‘English sequence of the’ vowél-sounds to be the most philo- 
sophical. The slender (a) as in paper, the open (a) as in father, . 
and the broad (a) .as in water, are also easily produced as varia- 
tions in sound of the first letter of the alphabet, and in English 
are rightly treated as. such. ; 
The sound of I (i) is produced when the back aperture re- 
presenting the fauces is constricted and that representing the 
lips left. open, and then the vibrating current of expired air 
is divergent within the mouth, becoming slightly rarefied from 
the first law of motion by which each particle tends to move 
in a straight line and with a uniform velocity, and experiment 
also shews this rarefaction to take place. Such a change in 
the vibrating stream of air we know by the properties of organ 
pipes and wind instruments generally affects the tone of the 
sound escaping to the open air. ; 
On the other hand the sound of U (0) as 00 In poop, 1s pro- 
23—2 
