The Pacific commercial advertiser. [volume] (Honolulu, Hawaiian Islands) 1885-1921, 1899-11-27
HOW IT is DONE
f. ]. Cross Describes Mar
Coni's System.
a Gigantic Battery = Transmitter and
Receiver Result of
Tests

All the world knows tha. 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
bat;e.y. but just how the marvellous
acc is accomplished is not generally
understood. In view of tine early in
PRODUCTION of the system into the Ha-
waiian Islands. an Advertiser report
er waited upon Mr.. F. 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 frs: 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 il, is a 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 a 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 lis power may be realized.
The Rhumkorf coils are of heavy wire
and are used as primary battery
They are. enclosed within, another Sc
r!eS 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 10 the vulcanized rubber insulator
a. the top OF the pole, and fixed there
in a perpendicular position; while from
the other terminal. wire is carried
into the ground.
The operating keys are identical
with those in ordinary use at telegraph
stations. bur, the waves from the i'm
Lensely powerful battery are carried
about three times as high again as the
length of the pole and there form a
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
90 wire from the top of another pole
OF the same height as the tranSmitter,
and is 4 glass tube from one and a half
20 two inches long. At each end and
leaving a space of one-fiftieth of an inch
between their ends. are Two silver
wires, of a 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 cO1neOced with another bat
terry and the sounder or receiving
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, anu dCludCIHS Jle SOUHleI
placed in the circuit; and the rapper
which strikes the tube and decoheres
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: if a book eight inches
thick. were placed between terminal
points, a clear hole would be driven
through it in fraction of a second.
Mr.. Cross mentioned, that at the
Naval Commissioners test of the sys
TEN. experiments were made to diScov-
er if the waves could be interrupted.
For this purpose a transmitting plant
was erected at iNaversink. and while
the warshipS New York and MaSsachu-
sets were in communication, this sta
ton kept up a shower of waves. for the
express purpose of interruptlng the
current: but in the series of twenty
eight tests only five were in any way
successful. But il must be remembered
that these interruptions were inten-
tional. and in our inter-iSland cOmmu-
nication, nothing of the kind need be
apprehended.
Another strange fact in this regard
is. shat If two points are connected.
the waves can be so focused that an
other station cannot miSdirect the mes
sage, even though il be in line with
points OF sender and receiver, and
either between them or behind the
latter.