The Hawaiian gazette., 1902-01-17
WIRELESS TtLEORAphf.

less telegraph. II says that n certain
Kind of electricity tends to travel Ike
waves made by dropping stone m
pond-ln all directions. But it travels
farthest and with ieast resistance in
those directions where 1t finds the best
conductors for it. Some substances are
better conductors than others. Glass
and rubber are non-conductors. social
ed. as you may see by looking at the
rubber covering OF wires on the street
car system, or the glass insuators on a
telegraph pole. Metals. such as iron,
steel and copper. are first-class con-
ductors. and that Is why wire is used
for telegraph and telephone and cleo
trio light purposes. Water and the
earth are conductors of electricity, and
so is the atmosphere. When Benjamin
Franklin. by his famous experiment
with the kite. proved that lightning IS
nothing but electricity. he also proved
that the atmosphere Is n conductor, for
bolt OF lightning may travel many
miles before striking the earth. Mere
space, finally. IS a conductor of cleo
triclty. as you can prove by passing
current through n vacuum.
AS soon as one comprehends that
electrical waves can move IN space
without the conventional wire conduc-
tors, 1t Is evident that the question OF
telegraphy with wires or without wires
must depend largely upon the trans
hitting and receiving apparatus. Wires
hitherto have been used because, with
the apparatus available for sending
and receiving electric currents, they
have afforded the best results; indeed,
for considerable distances they afford
ed the only results that could be de-
pended upon. Even with wire as con-
ductor, far more delicate receiving In
struments have to be used on an At
lantic cable than on circuit between
Springfield and Buffalo. Now Marconi
Is by no means the first one to expert
ment with wireless telegraphy. Many
men have been working at the prob
lem for years. And essentially their
problem has been to perfect apparatus
at one end which would generate cleo
trio waves strong enough TO travel long
distances, with mere space as the con-
ductor. and apparatus at the other end
sensitive enough to receive and record
,, those waves
The transmitting and receiving ap-
paratus thus far developed Is compli-
Gated, and one needs some technical
knowledge to understand 1t. You will
reach much about Hertzian waves In
! this connection. HertZian waves are
waves of electricity. Hertz was a Ger
man professor, who died in 1894. He
was the first man to prove by expert
ment that whenever In any circuit
electro magnetic changes are brought
about, as when an induction coil Is in
action. the disturbances are transmit
| ted in all directions. bringing about
| similar changes In neighboring conduc-
| tors. His great work was to show that
these disturbances are transmitted by
| means of vibrations of the luminifer-
Gus ether (Which Is assumed by physic-
, lists to fill all space), and also to show
! the character and measure the velocity
! of those waves. The wireless teleg-
rapher. therefore, first generates Hertz
| ian waves of electricity into space.
Gen. Greedy, head of the United States
army signal service, in describing the
transmitter used by the signal corps
in experiments. over two years ago, re-
ported that he used coil in oil. ZEN
ergized by "A three-quarter horse-pow-
er rotary transformer. furnishing 1875
volts alternating potential, an ar
rangement making "a very powerful
and efficient source of Hertz!an radia-
ton" Marconi used at that time a
Ruhmkorff coil. According to present
methods, the Hertzlan waves are
| transmitted by the generator through
a wire to the top of high pole, and
that Is where the jumping-off place Is.
From the top OF the pole, the Hertz
ian waves are radiated off into space
About one-fifth of a horse power is
necessary to send them sixty miles at
ought not to require much more than
3h horse power, provided the energy
can be utilized. To send the waves
across the Atlantic, the problem OF
transmission is question of propell-
ing force. The Hertzian waves follow
the curvature OF the earth.
Marconi improved the receiving ap-
paratus by discovering, or inventing.
what is known as the "decoherer /"
which consists OF ball working on
an arm attached to the armature of an
electromagnetic In the circuit of the
"coherer," or receiver. But that aside.
Enough has been said to show that this
apparatus. both sending and receiving.
Is highly technical, and difficult to be
understood In detail by one who IL no
electrician, or has never witnessed ex-
periments in wireless telegraphy. Suf-
flee 1t to say that when Marconi. the
other day. in Newfoundland, received
the wireless message from the coast of
England. he flew kite In the air, and
from the kite was suspended a wire
connecting with his receiving instru-
ment. The Hertzian waves had passed
over the ocean from the tall pole on
the England coast, and had struck the
wire on the kite in Newfoundland, The
electric vibrations were thus transmit
ted to Marconi's delicately adjusted re-
celver, and read by him exactly as
they had been sent across 1900 miles of
, ocean.
Marconrs system uses the atmos-
phere as conductor. Nicola Tesla, II
Is understood, is experimenting on a
system that uses the earth as a conduc-
tor. II seems safe to predict that sell
pnce will cDp1plataly tho pa,I