A NEW PHONAUTOGRAPH. 
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The vowel sounds gave complex harmonic curves, thus 
affording confirmation of their structure from certain partial tones. 
Consonants were scarcely recorded at all. 
This instrument had a more grave defect. The membrane 
of skin stretched over a brass ring possessed a tone of its own, 
and vibrated more strongly in resonance with this note than 
with others. 
Since the invention of the Phonautograph several other 
acoustical instruments of the highest importance have been 
invented. 
(1) Barloivs Logograpk, described before the Royal Society, 
in 1874, is an instrument for measuring the varying pressures of 
air in the cavity between the lips during speech. It consists of 
a trumpet-shaped mouthpiece, fitting almost tightly to the lips, 
which narrows, then widens, and is closed by a piece of elastic 
indiarubber, which bulges out more or less according to the 
pressure exerted by the air upon it. Against this elastic 
membrane rests a light lever of aluminium, hinged at one end 
to the supports of the instrument, the longer end of which 
carries a small pointed camel’s hair brush, which is charged 
with ink, and the lip of which touches a strip of paper carried 
beneath it by clockwork, like the paper strip of the Morse 
telegraph instrument. 
The traces obtained by the Logograph do not correspond, 
strictly speaking, to sounds at all, and do not represent sonorous 
vibrations ; they give the mechanical displacements of the air 
due to the change of wind-pressure in the cavities of the mouth 
during articulation. Vowels and musical sounds made no trace 
at all in the Logograph. 
(9) The Speaking Telephone of Graham Bell, invented in 
1876, first proved that metallic plates can accurately take up 
and reproduce the vibrations both of consonants and of vowels. 
(3) The Phonograph of Edison carried this discovery one 
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