The Indianapolis sentinel. [volume] (Indianapolis, Ind.) 1880-1904, 1885-01-18
Experiments with Deafness.
New York Tribune]

Are you engaged In experiments
other than those which YOU are making
with the. telephones?
II have here" answered Prof Bell,
unlocking a long, shallow black-walnut
case, something which may be of inter
est. 1t is an instrument for accurately
measuring the hearing capacity of the
human ear, and Is. as you see, composed
of one stationary and one sliding coil,
between two horizontal rods, on one of
which is graduated scale reduced to
the metric system. A telephone re-
ceiyer is attached to the instrument, and
the current is supplied by magnetic
electric machine, which has a wheel COM
posed of alternate sections of conducting
and non conducting surfaces, by means
of which the current is rapidly and regu-
larly closed and opened. A musical
sound is produced, which the telephone
receiver communicates to the ear. Hold.
ing the receiver to the ear, the operator
moves the sliding coil from the station
airy one, and as the distance between the
coils increases the sound grows fainter
and fainter, and finally is lost altogether.
The scale on the side rod MARKS the
point which the sliding coil had reached
when the sound ceased 10 be heard. Ii
standard of normal hearing capacity
can once be obtained, it will be an easy
matter TO measure the exact capacity of
every ear which is tested. Every ele-
ment by the use of this instrument is
calculable."
"Have you attained a sufficiently &C.
curate standard of hearingT
Not vet, but | hope TO soon. This
week have been making a number of
tests in the public schools of New York.
| have standard of abnormal, but not
of normal, hearing. find that this in
strument will be of great use in the pub
lie schools. 1t is estimated that 10 per
cent. of the school children of New
York city have slight defects of hearing,
and that one per cent. of this number
are so deaf that they derive no benefit
from the usual methods of instruction.
The scholars know, of course, when their
hearing is bad; but the teachers, as a
rule, do not, and often think child
dull when it is only deaf Ii the teach
ers were aware of the inirmity and un-
derstood it, the pupil whose hearing was
defective could always be given a posi-
ton in the room and classes which would
enable him to profit by the instruction
which he is now, in many cases, losing.
find great difference in the hearing
capacity of people. Some persons can
hear equally we'll with both ears, but
most persons have a greater hearing
capacity in one ear than in the other.
The hearing capacity ranges from zero
to an abnormal degree of acuteDess. By
testing the ears of several hundred per-
SONS will be able to reach an average
capacity of hearing which / can safely
take for standard"
How was your attention directed to
this subjectg'
"At Convention of the teachers of
deaf mutes, held in New York, / was
made chairman of a committee which
was appointed for the purpose of devils
ing means for testing and measuring the
hearing capacity of mutes. 1t has been
discovered that very large number of
persons who are classed as deaf mutes
have, in reality, considerable hearing
capacity. / have been able TO discover
this latent capacity by means of this in
strumeDt, and when it is found that
patient can be made 10 hear it is not
matter of great difficulty to develop the
hidden power and to teach the patient
to hear and speak, though, as matter
of fact, hearing is not necessary to
speech. l mean by that that deaf mutes
can be taught to talk, that in several
countries of Europe they are treated 50
successfully that more than 65 per cent.
OF them learn to use their vocal organs.
In the United States this matter has
been neglected, and only IA per cent. of
deaf mutes are taught to speak. Ii is
my hope that this instrument will be a
powerful factor iD the restoration of
speech and hearing TO a multitude of
persons, and | am extremely anxious
that it may become of use to school
children and 10 teachers. There are
probably 400 children in the public
schools of this city who on account of
defective hearing should be given special
advantages. | trust my invention will
be instrumental in discovering them.