Weekly Trinity journal., 1878-07-06
EDISON'S MEGAPHONE.


A New York Sun reporter had Ia III;
last week with Mr.. Edison about the
instrument with which he expects to en-
able deaf people to hear ordinary CONVEX
satlon, the words of actors in theater,
etc. II wanted" said he, "some simple
thing that deaf people could use in a
theater, church, or anywhere. had an
idea that could, if could get just the
right means for catching the vibrations
of air that produce sound, could carry
them into little box or chest that might
rest in mans lap as he sat. From that
chest tubes might run concealed in his
clothing to his ears. The point was to
find out just how to catch the sound vi
brations. You see, sound is produced
like Eight, by vibration. Wen, what do
you do when you want to get light from
a distant object, or if your eyesight is
bad, to see clearly something near 4?
Why, you make such aids to the eye as
will catch and carry to the eye the vi
brations of light. When you have done
this you see clearly. Well, now itstrucll
me that you'd got to treat the ear in the
same way, when anybodys deaf or wants
to hear something away off. But the tel
escope isn't good for much unless the
object glass which catches and focuses
tho light is just at the proper angle
What we want for the ear, then, on the
same principle, is an instrument the line
OF whose angle is exactly right. Then
you are going to get your sound vibra-
tions, because they will be caught and
focused. The fact is, I'D got to get an
ear telescope. Then we made that one, 81
pointing to the big funnel, "but it wasn't
right. 'Twouldn't work. Then we
made the other one
"You see that barn over there ~
pointing TO barn q mile or so Distant
"Well, | held this tube to my ear and
| heard man talking over there per
fectly. just as the telescope catches the
rays of light from star and brings then
to'a focus, so by pointing this tube direct
ly ut the spot that the sound comes from
you catch the vibrations of sound"
"Then this does magnify sound ?"
mo; only concentrates it. Now, this
angle is all there is to this take and
cut off u section fingers length from the
end, and so l get short tube with the
proper angle, suitable fora comparatively
short distance. If have enough ofthem
they will answer us we'll as one big tube
Now, perhaps, | can carry out my ideS
and make little chest, from which these
tubes viii issue. They will catch the vi
brations that are made when a man
speaks or breaches, and carry them into
the chest, and then they'll ppss through
the tubes to the ears. don't want to say
shat they'll do it, because haven't mad,
the thing yet and tried"
Edison proposes to rifle the speaking
tube Of the megaphone, so that the vibra
/ tions may be kept as compact as possible
/ Already some extraordinary experiment.
have been made with the rough cardboerC
ear telephone, and its utility for the pur
/ poses OF ordinary conversation for n dis
lance of two miles, was shown at Menl'
Park few days ago. 1t requires NJ
shouting. Even whisper can be hearc
two hundred yards away.
For field and long distance purpose
the megaphone will be mounted on !
ree-legged table like a surveyors in
strument. For audience rooms it ma,
rest upon tho lap, and of course has NJ
speaking tube.
Already letters pouW in upon Edisor
from deaf persons who have heard tina
he wes at work at something that viii
give them ears as spectacles give eyes tc
others. Sometimes he receives as many
as one hundred per day, and he had ,
batch of circulars printed, for it woulC
take his secretary all day to answer th'
inquiries. These are mailed to every ont
who writes.