The Hawaiian gazette. [volume] (Honolulu [Oahu, Hawaii]) 1865-1918, 1899-11-28
HOW IT IS DONE
F. J. Cross Des cribes Mar.
coni's System.
Gigantic osttevy- Tsassmitter sad
Receiver = Result OF
Tests

All the world knows tina: by Mar
coni's system OF wireless telegraphy,
communication between any two
given points is made through the me-
dunn OF sound waves, electrically
transmitted by an exceeding powerful
battery, but just how the marvellous
act Is accomplished IL not generally
understood. In view OF the early in
PRODUCTION Of the system into the Ha-
waiian Islands, an Advertiser report
er waited upon Mr.. +. J. Cross az his
home last evening, and that gentle
man was kind enough to furnish the
following particulars which will
doubtless be read with much interest.
In the first place, said Mr.. Cross,
there Is erected at the sending station,
pole Of about $50 feet in height, at
the top OF which and almost at right
angles with 1t, Is vulcanized rubber
insulator. eighteen inches long by one
inch in diameter. At the foot of the
pole is the station house, in which Is
placed the powerful Rhumkorf coil
battery. having q voltage Of from TO-
900 to 100000; and when one considers
that the voltage In an ordinary tele.
graph battery Is only some ten volts,
some idea OF its power may be realized
The Rhumkorf coils are of heavy wire
and are used as a primary battery.
They are, enclosed within. another Sc
ries OF fine wire coils used as the sec
ondary battery. Connected with the
primary battery are two brass binding
pos;s. upon which are fixed the brass
terminals, their ends about ten or
twelve inches apart, and across this
space the electric spark flies. From
one Of these terminals, a wire is car
ried to the vulcanized rubber insulator
at the top OF the pole. and fixed there
in perpendicular position; while from
the other terminal. q wire is carried
into the ground.
The operating keys are identical
with those in ordinary Use at telegraph
stations, but the waves from the i'm
mensely powerful battery are carried
about three times as high again as the
length OF the pole and there form
series OF Zigzag movements, at right
angles with the insulator. gradually
decreasing in magnitude until they
reach the receiving station.
The receiver or coherer Is attached
to wire from the top OF another pole
OF the same height as the transmitter.
to two inches long. At each end and
leaving space OF 0ne-fiftieth fan inch
between their ends, are two silver
wires. Of diameter sufficiently large
to fill the tube. The space between the
ends enclosed within the glass, Is filled
with mixture of nickel and silver
filings: and the exposed ends OF the
wires are connected with another bat
tS,t tvnaw
machine. through which the tape is
drawn.
The current having passed through
the coherer, Is carried away by another
wire and grounded. A rapper is fixed
in the center of the coherer and is in
circuit with the receiving battery. AS
the wave enters the coherer, the filings
stick together with such tenacity, that
the resistance Is reduced sufficiently
to permit the current passing
through, and actuating the sounder
placed In the circuit; and the rapper
which strikes the tube and decUheres
the filings increases the resistance
above the point OF allowing THE bat
terry current to pass. or, in other words,
stops the current and another impulse
from the sending station.
To give an idea OF the terrific force
of the electric spark at the trans
mitter end: II a book eight inches
thick. were placed between terminal
points. clear hole would be driven
through It In u fraction of a second.
Mr.. Cross mentioned, chat at the
Naval Commissioners test Of the sys-
TEN, experiments were made to discOv-
er II the waves could be interrupted.
For this purpose a transmitting plant
was erected at NaveHink. and while
the warships New York and MassaGhu-
setts were In communication, this sta
tion kept up a shower of waves. for the
express purpose of interrupting the
current; but in the series OF twenty
eight tests only five were In any way
successful. But II must be remembered
that these Interruptions were inten-
tional. and In our interdsland commu-
nication, nothing OF the kind need be
apprehsnded.
Another strange fact In this regard
is, that II two points are connected.
the waves can be so focused that an
other station cannot misdirect the mes
sage, even though 1t be In line with
points OF sender and receiver. and
either between them or behind the
laffar