The Salt Lake herald. [volume] (Salt Lake City [Utah]) 1870-1909, 1894-01-21

AAONO -
a singers voice, each vowel sound, is
made up of combination of vibra-
tons peculiar to itself.
Even the same word sounds diff
ferently when spoken or sung on the
same note by two different persons,
and this difference is due to the fact
that one voicing of the word contains
some vibration which is not in the
other, or that the same vibrations are
found in different proportions in the
two voicings.
All these vibrations are taken up
and repeated in their proper proper
ton by the little iron disk in the tele-
phone.
Fastened to the back of the disk is
a peg which touches a piece of carbon
or charcoal, resting on or against
metal plate. By means of this arrange
ment, when the disk vibrates, the car
bon is pressed against the plate a great
many times in a second. but at ir-
regular intervals and with varing force
mo two sounds affecting it in ex-
actly the same way.
This piece of carbon forms part of
an electric circuit. That is to say, one
point of 1T is connected by a wire to
one pole of an electric battery, and the
metal plate against which it rests is
connected to the other pole of the
battery by a second wire, the greater
part of which is rolled UP into a small
coil or spiral
A current of electricity consequently
flows through the carbon and the wires
continually. But it is an irregular or
varying current, because whenever the
carbon is pressed its particles are
forced closer together, and then con-
ducts electricity better and allows a
stronger current to pass.
Therefore every vibration of the little
disk, and consequently every one of the
vibrations which make up the original
sound, causes a change in the strength
or the electric current-a stronger vi
pratlon causing a greater change than
feeble one. So we have what we NAV
call a vibrating electric current, which
exactly represents the sound yibrat lions
of the speakers voice.
Now the line wire running to the
central office does not receive this err
rent directly, nor is the line wire in
direct connection with any electric
battery. The line wire is connected
however, to a spiral coil of wire which
surrounds the coil already mentioned.
| whenever the current in the first
! coil grows stronger a. current in the
opposite election is poduced-or. as the
electricians say, induced-in the second
COIL grows weaker, a current in The
same direction is induced in the sec
ond. Now, as the current in the first
coil is hanging continually. the result
is that a second vibrating current. also
exactly representing the speaker
voice, flows in the second coil and along
the line wire.
(F'or very short distances both these
coils may be removed, and the plate
under the carbon connected directly
with the line wire, but for long dis.
tances the arrangement described is
better-for reasons which it would take
too long to explain)
eve will suppose that your friends
message is now translated into electri.
city and is travelling over the wire
through the central office, to your re-
celvlng telephone, which will trans
you.
The receiving telephone 6he little
instrument hanging on the cord be
side the box, which you hold to you]
ear when you are receiving a mess3ge)
consists of a long straight magne
about six inches long, a thin iron disl
nearly touching one end of the mag
net, and a coil of fine wire surround
ing the same end.
The coil of wire around the magma
is connected with the line wire (by {
small wire concealed in the cord, ant
therefore receives the vibrating curren
which represents the message,
Now an electric current f1owins
through a coil Of wire around an irof
bar makes the bar a. magnet for tn,
time being. When the current ceases
the bar at once loses nearly all it,
magnetism; and when the direction O.
the current is reversed, the magnetism
is reversed also, the North pole becom
ing South pole and the South pol,
a North pole.
A current flowing in this way arount
a bar which is already magnetized viii
increase or diminish it's magneti
J. strength according to the direction tn
current.
So the strength of the telephone mag
net, and consequently it's attraction 70
the little iron disk, change continual,
under the influence of the vibratin,
current. The disk is therefore made t
vibrate very much as the other disk
against which your friend spoke. vi
brated, and these vibra tons, being con
veyed by the air to our ear, reproduc
almost exactly the sounds of the speak
ers voice.
; Now the receiving telephone is on
of those instruments that can be "ru
z backwards" as we'll as forwards. Tha
is to say, if you hold it to your mout
J and speak, your voice will make it
, disk vibrate, each motion of the dis
) will slightly alter the magnetism G
the bar magnet, and each change in TIL
: magnetism will induce current in tn
surrounding wire.
If two of these little receiving in
Z struments, therefore, are connected b