The new dominion. [volume] (Morgantown, W. Va.) 1876-1904, 1878-07-06
EdisOn's Megaphone.

"A sun reporter nau Talk last week
with Mr.. Edison about the instrument
at which he is working, by means of
which he expects to enable deaf people
to hear ordinary conversation, the words
of actors in a theater, etc. " | wanted y
said he, some simple, convenient thing
that deaf people could use in theater,
church or anywhere. | had an idea
that, if / could get Just the
right means for catching the vibrations
of air that produces sound, | could
carry them into little box or chest,
that might rest in mans lap as he sat.
From that chest tubes might run con
cealed in his clothing to his ears. The
point was to find out just how to catch
the sound vibrations. You see, sound
is produced like light, by vibrations.
Well, what do you do when you want to
get light from distant object, or if
your eyesight is bad, to see clearly
something near. Why, you make such
aids to the eye us will catch and carry
to the eye the vibrations of light. When
you have done this you see clearly.
Well, now it struck me that you'd got
to treat the ear in the same way, when
anybody's deaf or wants TO hear some
thing away off. But the telescope ism t
good for much unless the object-glass
which catches and focuses the 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 vibrations,
because they will be caught and
focused. The fact is, I'd got 10 get an
ear telescope. Then We made that one,
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 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
them to focus, so by pointing this tube
directly to the spot that the sound
comes from you catch the vibrations of
soundY'
"Then this does not magnify sound T'
No; only concentrates it. Now,
this angle is all there is to this. / take
and cut OIL a section fingers length
from the end, and so get short tube
with a proper angle, suitable for a com
paratively short distance. If | have
enough of them, they will answer as
well as one big tube. Now, perhaps
can carry out my idea and make little
chest, from which these tubes will issue.
They will catch the vibrations that are
made when man speaks or breaches
and carry them into the chest, and then
they'll pass through the tubes to the
ears. don't want TO say that they
will do it, because | haven't made the
thing vet and tried"
Edison proposes to rifle the speaking
tubes of the megaphone, 50 that the
vibrations may be kept as compact as
possible. Already some extraordinary
experiments have been made with the
rough cardboard ear telescope, and its
utility for the purposes of ordinary con-
versation for distance of two miles
was shown at Menlo Park a few DAYS
ago. 1t requirers no shouting. Even a
whisper can be heard two hundred
yards away.
For field and long distance purposes
the megaphone will be mounted on a
thr' e-legged table like surveyors in
strument. For audience rooms it may
rest upon the lap, and, of course, has
no speaking tube.
Already letters pour in upon Edison
from deaf persons who have heard that
he is at work at something that will
give them ears as spectacles give eyes to
others. Sometimes he receives as many
as one hundred day, and he has had a
batch of circulars printed, for it would
take his Secretar all day to answer the
inquiries. These are mailed to every
one who writes.