The Indianapolis journal. [volume] (Indianapolis [Ind.]) 1867-1904, 1901-12-22
MARC0NI'S ACHIEVEMENT
POPULAR EXPLANATION or THIS
NEW SYSTEM OF TELEGRAPHY.
One Feature Is a Vertical Wire whose
Length Depends on Distance
TO BE Covered.

AdHluBe, was puDllSneu III EleClTlClly III Is
issue of Dec. 13, 1899:
Almost exactly half a century after
Morse. in 1874. startled the world by ticking
of that apt message, What hath God
wrought, a rumor spread in scientific cir
Giles that a method of transmitting signals
through space without wires had been dlS-
covered. That this seemingly Impossible
feat could really be accomplished was ultl-
mately proved beyond a doubt and was
mainly due TO the Investigations or Helm
rich Hertz. a young German physicist.
Hertz demonstrated about 1883 that an cleo
trio spark under certain conditions pro-
duced electrical oscillations or waves which
Travelled in all directions through space. In
much the same way that waves created In
a quiet pond by the throwing I'm of a stone
radiate.
"a year or two later a French scientist
by the name of Brandy working along the
same line made the startling discovery that
metal filings packed loosely together In a
glass tube. and having formally a very
high electrical resistance, became conduc-
tors and readily allowed an electric current
TO pass through them when they were
struck by an electric wave such as was
demonstrated to exist by Hertz.
with these two discoveries as a basis
the present system of wireless telegraphy
has gradually been evolved, by devising
sent out from the transmitter and by so
arranging the tube with metal filings as
to cause it TO faithfully respond to the
blows from these same waves.
"Of the various inventors who have been
endeavOring TO perfect wireless telegraphy
apparatus none has proved so successful
as Mr.. William Marconi, a young Italian
scientist.
"Mr. Marconi was born at Griffone. near
Bologna. on April IS. 1874, and is now con-
sequently in his twenty-eighth year. His
mother was an Englishwoman and this
probably accounts in some measure for the
almost entire absence of foreign accent in
his speech. Ever since the age or fourteen
Mr.. Marconi has been keenly interested in
plpCtricitV and during the past four or
five years has been working on the prob
lem of wireless telegraphy without inter-
mission. Most of his experimental work
has been carried on in England since July.
1896, and in this connection ii may be OF
interest to state that on his arrival in that
country he received a rather rude welcome
by having his instruments broken up and
destroyed by ignorant custom house Off
Gals who mistook them for Internal ma
chimes.
HIS OWN APPARATUS.
T creditable results so far obtained by
Mr.. Marconi both abroad and in this coun-
try are unquestionably due to the appara-
tus of which he makes use. The device by
means of which the signals are sent, or the
transmitter, as it is called, is what is
known as an induction coil. This consists
of a cylindrical bundle of soft iron wires
upon which two separate coils of insulated
wire are carefully wrapped. The first of
these coils, of reasonably heavy iron and
of one or two layers in depth only is known
as the primary While the second wrap
ping, consisting of very many turns or fne
wire, is called the secondary In the Mar
conf transmitter the primary winding of
the coil is connected with a number of dry
batteries, such as are employed for bell
ringing purposes, and will an ordinary
Morse telegraph key, thus making a COM
plete electric circuit, while the secondary
winding is connected to two brass balls
about an inch and one-half in diameter,
which are placed about an inch and one
half from two larger brass balls whose in
ner hemispheres separated from ore an
other by the thirtieth of an inch are in
closed in a heavy rubber tube filled with
oil. To one of, the small brass balls Is at
tached a vertical conductor anywhere from
twenty to two hundred feet in height, de-
pending on the distance 1t is desired TO
transmit a message, while the other small
brass sphere is connected by means of a
similar wire with the ground.
when the telegraph key in the primary
of the induction coil is closed an electric
current flows through the circuit and ere
ates a very great difference in electrical
pressure in the secondary winding, and
thereby causes sparks to pass across be-
tween all four balls and through the oil
bath. In other words the action much re-
sembles a discharge of lightning. only, of
course. on a miniature scale. These dis
charges create the electrical waves already
referred to as having been discovered by
Hertz, which oscillations may either be
sent out into space in the form of long or
short waves by holding down the telegraph
key for a longer or shorter period. In this
way ordinary Morse Geographic signals,
consisting of long and short strokes, or
dots and dashes, are sent out in the form
of electrical vibrations.
RECEIVING INSTRUMENTS.
Now, In order to receive the signals in
diligently recourse is had to Branly's in
vention. This consists, as already stated,
of what is known as a coherer or a small
glass tube about an inch and a half in
length and one-thirtieth of an inch internal
diameter, fitted with two plugs of silver. to
which platinum wires are soldered, the re-
manning space in tlS tube being filled with
a mixture of nickel and silver filings. This
sensitive tube is connected in a circui, with
an electric battery, a high resistance tele-
graph relay and sounder.
Under normal conditions the filings in
the coherer will not allow of the passage
of the electric current from the battery,
but as soon as the electrical wave sent out
from the transmitter strikes a vertical wire
similar to that on the sending instrument
and connected with the tube, the filings.
so TO speak, weld themselves together. or
cohere, and allow current to pass for a
lOnger or shorter interval, depending on
the length of the wave sent. This current.
in flowing around the circuit. operates the
relay and sounder and enables either a dot
or a dash to be recorded.
1T is found. however, that once the
filings in the tube have responded to a
wave from the transmitter, they remain
welded together until such time as the
tube has been struck a smart tap, when
the filings loose up or decohere and the
tube returns again TO its state of high
resistance. Now, in order to transmit
Morse signals il is manifestly evident that
some means has to be devised for tapping
the tube automatically. For this purpose
Mr.. Marconi makes use of a little vibrating
hammer attached 70 the sounder, which
after every wave automatically strikes the
tube a sharp blow, thus loosening the
filings and permitting another wave to be
recorded.
with the apparatus described a speed of
about twenty words a minute is obtainable.
and by employing in every case the high
vertical wire, which intensifes the wave
effect and which is original with Mr.. Mar
conf. the latter has gradually succeeded in
increasing the distance over which intel
ligible messages can be sent from three
miles in May. 1897. 10 over eighty miles in
September, 1899"
He kept on improving his apparatus, 1900
extending the distance covered. and on the
first day of Edward Wis reign. Jan. %.
1901. he performed the remarkable feat of
communicating between st. GATHERINGS on
the Isle of Wight and the Lizard, 20 miles
away. Since that time various advances
have been announced. and il was claimed
by the Marconi people that crossing the
ocean was only a matter Of a very brief
time.