The Pacific commercial advertiser. [volume] (Honolulu, Hawaiian Islands) 1885-1921, 1900-09-29
THE ELECTROMAGNETIC.
How Your Instrument May be Made to
Record Messages.

Of telephone and monograph, enabling
the sounds of the one to be recorded by
the other and preserved for use at some
later period, by merely inserting in the
circuit of the telephone an apparatusl
ed by few loops of wire, and piece
of steel wire wound on a barrel with
clockwork to make that barrel turn
around. By its use we are able to get
tenfold value out of our telephone for
the same money.
Jones gets thirsty and goes for a
drink. Hardly has he turned his back
on the door of his office when his law
yer calls him up on the phone to say
that that damage case of his is going
to be tried on Thursday at 1890 and he
had better put in an appearance. Mrs.
Jones is waiting at her end of the wire
to inform her husband that she's COM
ing down to the office to get some
money and will be there at $3.50. Then
Bangs the broker, wants lot OF fig
ures so that he can go ahead and fix up
that little business of which they were
speaking. And Smith wants some
thing, etc. Jones all this while is calm
ly enjoying his drink, sweetly uncon-
scious of the press of business at his
office When he gets back all he has TO
do is to press the proper button or turn
the proper switch and the lawyer re-
delivers his message, Mrs. Jones gives
warning of her approaching visit,
Bangs again requests his data and
Smith states his wants. After attend
ing to all these various matters Jones
turns another switch and, figuratively
speaking, the slate is wiped off and
ready for another record If Jones should
happen to get thirsty again. Or, again,
Jones is deeply engaged making
rough mental calculation of the essen
tial items of some speculation when,
tinG-a-ling goes the call bell and Mrs.
Jones wants to remind him that he
must stop for that umbrella handle on
the way home, and must not forget to
stop in at Green's and tell them to send
up five pounds of sugar, ten pounds of
oatmeal and four pounds of coffee, Java
and Mocha mixed, and while he is about
1t he might order the flowers for Mary's
wedding, and, whatever he does, he's
not to forget to change those books at
the library. Now Jones, instead of get
ting excited and saying those things
which he ought not to say, quietly let's
Mrs. Jones get through her little list
and then, sends the bellboy to the
| phone to have what Mrs. Jones said
repeated and written down, and if the
boy doesn't get it right the first time he
can have it again and again.
The recording and repeating of
sounds, once made by the telephone, is
not, however, the masterpiece of the
telephonograph. The possibilities it
opens up are marvellous. A news
agency can telephone to an unlimited
number of subscribers simultaneously,
and, if necessary, each and every par
| ticipant can keep record of the ma
terial sent him. The action of the tele-
monograph is such that the repeated
sounds are stronger than the original.
a featurewhich adapts it to use as re-
! lay.
Its Importance has been recognized
! by the highest authorities of the Ger
man Postal Service. They have been
lclosely following the experiments made
by the inventors wi apparatus con-
structed by the best manufacturers OF
photographic apparat IS in Germany
Valdemar Poulsen, a Dane by birth, is
the originator of the invention, but he
was materially assisted by his colab-
orator, p. o. Petersen.
| The underlying principle of the inven.
ton is as simple as the apparatus re
sulting therefrom. The residual mag
netism contained to some degree in al
i iron is CORRESPONDENCE affected by th'
proximity of the magnet. Any one cal
prove this for himself. Take a piec,
of iron and draw an invisible line OF
it with magnet. On scattering som,
iron filings equally over the surface o
the metal the line that could not be seei
before will become distinctly visible
Corresponding to the polarity of tn
residual magnetism in the plate of irol
j and that of the magnet, the densit.
along the line drawn by the magnet viii
be distinctly greater or less than any
iwhere else. Poulsen's invention is base,
son this nutabiIity of residual magnet
ism. A steel wire. wound in groove
on cylindrical drum or barrel, is un
9 der the influence of a small electro
q magnet, which can be made to Gid
Q along the entire length of the wire b,
0 turning the barrel and causing tn
7 magnet to move sideways correspond
4 ingly. The core of this electro mag
a net is an iron wire one-twenty fifth O
a an inch in diameter, arranged so tina
the steel wire on the barrel glides be
, tween it's two ends. When the electr
. magnet is excited by constant cur
q rent and the barrel set in motion by tn
. lclockwork the wire will be equally mag
q netized from one end to the other, /. e
a every section will contain the sam
n amount of residual magnetism. WheI
N however, as is the case with an electr
magnet, which is excited by the cuI
rent of telephone. the polarity of tn
inscriber. as the magnet is sometime
called. is continually changing, the re
= sidual magnetism of the recorder 9th
steel wire of the barreD also varies, be
ing either weakened or strengthens,
~ The result is that the steel wire cor
tains continually varying degrees
- magnetism along its entire length. No
IL is one of the first laws of inductio
- that any change in magnetism near
loop of wire will induce an electric cu1
y rent in the latter. provided it be
IL closed circuit. To make a long ",
=. very simple) story short, the steel viii
N Is now able to induce in the coils of Il
u magnet a current exactly correspond
q. ing in alteration to the original curren
N and when, therefore, the switch s
turned and the clockwork is set in m,
5 ton the sounds telephoned in the fir
place are repeated. A message was r
peated 1,200 times without showing Il
slightest traces of weakening, so TIL
it may be said there is almost no lin
TO the number of repetitions. Nor
over, the repeated sound is strong
y than the original
p There are three representative typ
I'd of the instrument. In the first a ste
ne wire one-twenty- on an inch
'y diameter is wound on a barrel (,
al inches long by five and one-half inch
le In diameter. This apparatus is go.