Public ledger. [volume] (Memphis, Tenn.) 1865-1893, 1878-05-23

lie hoarseness of tones as we'll as a
slight falling off in the volume of
its utteranees. Many attribute this
to the use Of a tin trumpet in de-
livering the sound, and experiments
have since shown this supposition
to have been correct. Long ago
Mr.. Edison had realized the neces-
sity of utilizing some other and less
defective medium, more sensitive
and less resonant in material and
construction. After many failures
he succeeded in supplying this want
by constructing delivery horn out
of new substance, compounded
mainly out Of catchouc, gelatine
and the sensitive carbon which en-
ters so largely into Mr.. Edison's
manufactures. A modification was
also made in its shape and construc.
tion, more especially adapting it to
the needed purposes. Upon the
very first time it was Gound,to be
almost perfect in action, repeating
the voice with such absolute fidel-
ity in tone and infection as to ac-
tually Startle the experimenters
themselves.
Upon the subsequent day, while
again testing its merits, the tube
portion Of the trumpet accidentally
became twisted, when the ever
watchful ear of the inventor at
once detected an increase of volume
of sound. His attention was at
once directed to the economy of the
convolution Of the human ear, and
the problem presented itself as to
whether they do not embody a me-
chanical principle. 1t was not long
before this secret yielded itself to
the prying search Of the wonderful
inventor, who discovered it by
curling the neck or pipe of the
trumpet in peculiar way and by
adding to its cOnyolutions, the
faintest sound-waye could be made
to recall itself through the medium
OF the dlaphram, upon the receptive
plate or matrlx, as deeply as the
loudest tone uttered under ordinary
conditions. In short, he succeeded
in demonstrating the fact absolute
ly that by means of proper mechan-
ical arrangements the volume OF
sound capable of being emitted by
the phonograph was actually limit
less, and entirely Independent of
the application Of steam, air, valves
or any extraneous force.
Impressed with the value of both
these discoveries, it was natural
in Mr.. Edison to set about COM
bining the two, result he accom-
plished with little difficulty, the
operation of which is to be wit
messed at his laboratory in Menlo
Park, and which he has named the
"Auaphone."
The new invention of Edison's
is briefly described as follows: In
the ceiling of his private office, con
cealed from view, with the excep-
ton of a small, ear-shaped tunnel,
of dark color, he has fitted between
the ralters ana the floor above one
of his douhle-recording and speak
ing machines. In the room above
portion of the machine rises
through the floor, and attached to
it is a small wooden box, said to
contain the coils of the pipe of the
trumpet, the bell or mouth of which
opens through one side, and is made
of the new substance discovered by
Mr.. Edison, and is alluded to else
where. With the exception of the
box, all other portions of the ma.
chine are open to inspection. Every
word uttered in the room below is
repeated in the room above, with
about treble or Quadruple the vol
ume of sound (although it can be
arranged in vast excess Of this),
while at the ssme time it is being
recorded on the matrix plate for
future reference and preservation
through the electrotyping process.
The effect produced by the aura
phone is not only comically weird,
but in many ways alarming.
Sending an assistant to the room
below in order to test its capacity
for catching whispers, the orator,
directed by Mr.. Edison, bent down
his ear to the little box only to be
deafcned by the inquiry, "What do
you think of the auraphone?"
In tones that almost made |
the house rock, followed bya laugh |
so mockingly hideous aud unearth-
ly as to make the blood cnrdle with
horror. This we soon discovered to
be one of the peculiar jokes Incl
dental to an Introduction to thesau-
Iaphone, always hugely enjoyed by
the inventor and his attaches. Sub
experiments proved the ex-
luisite sensitiveness OF the machine.
The faintest whisper, the ticking of
4 clock, the rolling of a lead pencil
over the desk, the tearing of a
small piece of newspaper, sigh, a
tune hummed in the lowest regis
were successfully delivered
IN the room above in exaggerated
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