The times., 1899-04-16
THE new WIRELESS
TELEGRAPH SYSTEM
Description of the Experiment
tai Apparatus Used.
Practical Tests Made by the War
Department.
Prospective Communication with
Fort Myer-What Marconi Says of
Fents Already Accomplished.

Perhaps nothing is attracting more at
tention in electrical circles at present thsn
the wireless telegraph, which, though still
in an embryonic stage OF development.
gives every promise of becoming one of the
scientific marvels of the age.
The leader in the new system of trans
mitting messages without the use of wires
is G. Marconi, the young Italian scientist,
whose achievements have astonished Eng
land. where the experiments have been
made, and attracted the attention of the
world. Among the most important OF the
experiments to perfect the wireless tele-
graph are those now in progress in Wash
ingion under the direction of the Signal
ofIlce of the War Department.
The department intends to give the Mar
conf system thorough test, with a view
10 adopting it for use by the Signal Corps
of the army.
In order TO conduct its experiments, the
department has purchased a receiver and
sender of the Marconi pattern in which
slight notifications have been made and
will be made as experience teaches the de-
fects of the instruments which are neces-
sarily yet crude in form.
Experimental stations have been located
State, War and Navy Building and at Fort
Myer. the army post on the west side OF
the Potomac, opposite the capital. The
distance between these experimental s.a-
ticns is six miles.
The War Department has already made
several minor tests with the Marconi sys-
TEN and has secured satisfactory results.
but the apparatus is being adjusted SO as
10 try communication either between tie
Myer, or the Washington Monument and
the army post named. The apparatus Is
being arranged and the experiments being
conducted by Colonel James Allen Nand
Lieut.. George o. Squier, both of the resu-
lar army.
The experiments of the War Department
with the wireless telegraph are being
watched with extraordinary interest by
those who follow electrical progress and
the project has also attracted popular at
teEJioa.
The Mnrconi System.
A description of the Marconi system of
wireless telegraphy is of particular inter-
est, in view of the experiments being
conducted in Washington. The system is
based upon the utilization of the Hertzian
magnetic waves which travel through the
luminiferous ether with the velocity OF
light. and. In fact. We're declared by their
diseoverer Prof. Hertz CT CarlsIuhe, to be
identical with light, except that the waves
are of greater length. Whenever an eiec-
tric spark is made to jump from one cleo
trode 10 another these waves are produc-
ed. and their rapidity may be varied By
variations in the ark-prodrcing appara-
tus. so that instruments used for sending
and receiving signals through their medi-
-.
made inyulnerable to the attacks of other
waves of dissimilar periods. Wherever
these magnetic waves reach they affect
all magnetic material and thus make il
possible to use them as a means OF carry
ing messages.
II was also discovered that the Hertz
waves. although radiated like light, in all
directions. il set into motion from a free
source. can be reflected and directed, just
as light is. by means Of mirrors. II. there
fore, YOU imagine an electric circuit in a
house. with key in il, just like an ordi-
nary Morse telegraph circuit, you have the
basis of Mr.. Marconis system. This cir
cult runs through spark coil with an
oseillator or interrupter, 10 produce con-
finuous sparkling SO long as the circuit Is
kept closed by the key, and from this the
secondary or sparkling wire runs out of
doors and to the pole from which the mes
sages are TO be sent. The two ends of the
wire terminate in small metal spheres,
between which the sparks pass.
When Marconi began his experiments
this was the complete form of his sending
apparatus. and readable signals could only
be sent a few yards. In his present form
of apparatus one of these wires is extended
10 the earth. and the other has an extension
carried vertically into the air, and the
length of this latter wire bears a di-
rect relationship TO the distance over which
signals can be sent.
The Receiver.
Marconi also found the basis OF his re-
eeiving apparatus already invented for him
by Prof. Calzecchi onesd of Fermo and
improved and modified By others. This re-
ceiver is what is known as as a coherer
The idea upon which it Is made is that Il
you take an electrically conducting mater.
iai like iron and break it up into small
particles like filings the intervals which
separate these particles would prevent thi
mass from allowing any current from pass
ing through Now, if you were to bring
magnet near the mass OF filings. each par
ticie would become magnetic, draw itsel
close to its neighbors, and the mass woul'
become so solidified as to establish through
ii an electrical channel.
ment just such an apparatus. 1t consists
OF small glass tube four centimetret
long, partly filed with filings of nickel an,
silver. At either end Of this tube ant
reaching into the mass of filings is ter.
minal wire OF an ordinary Morse rela!
magnet circuit. One wire runs TO tn.
ground and the other connects with tht
magnet. the battery and the ground. Ths
armature of the relay magnet opens ant
.-g- IL,
operates a recording instrument and also
little hammer which continually taps the
coherer to shake the filings apart wher
they are not being held by magnetic at
traction The eoherer is set up on a pole
side by side with the sparkling spheres
with a similar vertical conductor. Tbs
Hertzian waves have the quality of a mag
net in causing the filings in the tube tc
adhere TO one another. and the manner o
the operation Of the system is simple.
The operator presses his key. Just as II
ordinary telegraphing, making his alpha
bet in dots and dashes. As the wave:
shoot out and with the velocity of ligh'
reach the receiving station miles away
the filings in the coherer there draw to-
gethsr. and a current passes through then
which draws up the armeture of the rela,
magnet. This closes the circuit of the re-
cordtng instrument. and although the tap
per is set TO work to shake the filings
apart. the magnetic waves come to IL witt
such rapidity, each one re-estabIishing tn.
conference, that the slower acting recording
instrument is not disturbed, and it con
finues to record the signal so long as thu
far-away operator keeps his finger on ths
key. The tuning Of the coherer to wavei
OF different frequencies Is done by at.
faching to each end OF IL a copper strip
and the length of these strips determine
their susceptibility TO different wave tones