New-York tribune., 1900-07-08
THIS TELEPHONE RECORDS.
AN INTERESTING DANISH INVENTION
AT PARIS


sponse, has wished that there might be some
registering apparatus at the other end of the
line to take down his message, and good deal
of attention has been given by telephone eX-
perts to the invention of an instrument which
would accomplish this object The first men to
realize the idea however, are two Danes, '.
Poulsen and p. O. Petersen. They call their
device the 'telegraphone." 1t is on exhibition in
Paris, and although it has not created a popular
sensation, it has awakened the interest of cleo
tricians.
1t would seem to be a simple matter 50 to
combine a telephone and phonograph as to serve !
the purpose here indicated, but such has not
proved to be the Edison's famous inven-
ton has thus far failed to work a telephone
repeater. And though it has furnished Messrs. |
Pousen and Petersen with useful suggestions /
regarding the general form of their instrument, |
they have found it necessary to employ diff
ferent principle
In a phonograph the message is inscribed I
upon wax cylinder, rather wax shell ad-
justed to the cylinder. Variations in mechanical
pressure. and not electrical vibration, do the
business. They leave upon the waXen surface
a series Of indentations of different depths but
all clearly visible to the naked eye Provision
is made for slowly shifting the position of the
cylinder endwise, as it rotates, 50 that the mes
sage may be inscribed in a close spiral. The
wax shell may lie used for reproducing the sound
200 or 800 times, but after that the wax be
gins to yield, and the utterance grows indis-
tinct
In the system of Messrs. Pousen and Peder-
sen the essential thing is a steel wire, one
twenty-fifth of an inch in diameter wound in
spiral about a cylinder which has the rotary
and sidewise movements of phonograph The
wire is gently embraced by the tips Of a tiny OBJ
ject that looks like a microscopic clothespin,
and which remains practically stationary while
hot he
manner about to be described, leaves upon
the wire a record that is absolutely invisible
under the microscope. The impression
is made not by mechanical pressure but by
magnetism.
The device whose tips rub against the wire
is small electro magnet. The minute coils
of copper wire that surround it receive cleo
trical vibrations from the telephone transmitter.
1t is a well known fact that when such fuctu-
ations occur in d wire that encircleS bit of
soft iron the intensity of the magnetism in the
latter varies in exact correspondence. Hence
rapid though slight, changes in the power of the
electrO-magnet just referred to are produced
automatically by the telephone. The poles of
the magnet impart magnetism to the steel wire
which they embrace and here again the effect
produced varies with the fluctuations in the
power of the magnet Different parts of the
wire then. differently magnetized. The
magnetism stays where it is put. The wire is, to
all intentS and purposes, series of tiny mag
nets joined to each other, each having a greater
or less strength than its neighbor.
If. after the cylinder has carried all of the
wire through the prongs of the cOthespn, it be
set back and started again, and If the magnet
now be connected with telephone receiver in
stead of a transmitter, a person can hear the
original message or piece of music by placing
the receiver to his ear. The magnetism i'm
pressed the wire will react the electro
magnet whose poles in contact with it, and
the difference in the intensity of the former will
produce fluctuations in the power of the latter.
The magnet in turn will create vibrations in the
electrical current that flows through its coils
and through the telephone receiver. Thus the
original process is reversed
The wire may be used in this manner 900
300 times. it is asserted Eventually. how
ever, the message may be washed off, il were,
by drawing the wire between the poles of the
magnet when uniform current is supplied by
battery. and when both telephone transmitter
and receiver disconnected.
For long communications Messrs Poulsen and
Petersen substitute for the wire a steel tape an
eighth Of inch wide and 1-5OO of an inch in
thickness This is not wound on a cylinder but
transferred from reel another under
tension sufficient to keep it fiat. Ii is worthy
note that a message which has been impressed
on wire tape in this manner may be sent