The Pacific commercial advertiser. [volume] (Honolulu, Hawaiian Islands) 1885-1921, 1904-07-05
WIRELESS TEL[GRAPHY
IMPROVED BY De FOREST

| 1t Is some years since wireless tele-
graphy first extended popular magma
ton to the utmost and found it lament
ably deficient in powers of comprehen-
sion: but the vagaries and accomplish
ments of the mysterious Hertzian
| waves do not fail to fascinate us as
they did in the days of their novelty.
There is an eerieness that is almost
comic in the possibility of messages
ever wandering silently over house
tops, playing round chimney-pots, and
passing through brick walls as though
| they did not exist.
/ Such possibility seemed to most
unscientifc people a very remote one
but the recent accomplishments of the
| De Forest system on board the Times
steamer Haimun in the Far East lead
US to believe that the date is not so far
off as has been imagined.
The success of the De Forest system
of wireless biography must be regard
ed as one of the greatest feats of the
war. The inventor is one of the first
men to make wireless biography con-
sistently successful for commercial pur-
| poses, and by its aid the Times is able
| to receive from the seat of war long
uncensored accounts of the operations
both on land and sea.
Dr. De Forest is a graduate of Yale
University. His rise to fame has been
as rapid as ii is well deserved. Ten
years ago he was pushing a bath chair
at the Chicago Exhibition in order to
get money to finish his college educa-
ton; at the forthcoming st. Louis Ex-
position his exhibition will be one of
its chief features, and will comprise a
tower 800 feet high, and four wireless
stations throughout the grounds.
The best testimonial to the De Forest
system is its own success on the Hal
nun. This steamer was chartered at
Shanghai at the outbreak of the war,
and the wireless apparatus was INSTALL
ed by De Forest operator. A topmast
was rugged up to the height of 70 feet
and gait was attached from which
wires or antennae ran down to the OPP
orators cabin. The station which re-
ceives messages from the steamer is
ten miles east of Wei-hai-wei. A ban-
boo mast $50 feet long is reared by the
antennae are attached in similar fash
ion to those on the Haimun.
When sending a message the operator
sits in his cabin on the steamer and
clicks word after word Oft on the Morse
key in front of him. AS hi, electric
battery begins to work sparks appear
at the gap in the circuit. These sparks
cause the vibrations of the ether which
are caught up by the antennae and car
ried out into the atmosphere, where
they dispense in exactly similar fash
ion to the little waves caused on the
surface of a pond when a stone is
thrown in.
The receiving station at Wei-hai-wei
is in sympathy with the transmitting
station on the Haimun. Without this
mutual sympathy there could be no
possibility of the messages reaching
their intended destination. AS it is,
however, the antennae at the receiving
station are struck by the other waves
set in motion by the electrical disturb
ance on board the Haimun, and convey
the vibration down to the responder
before which sits the operator ready to
receive the message.
1t is in the use of this responder"
that the De Forest system differs so
much from other systems. Previously
a "coherer'' was used as the chief in
strument in receiving message. This
"coherer'' in principle is a break in the
receiving circuit, which is bridged over
by metallic filings. When an electric |
wave falls on the filings they arrange !
themselves SO as to complete the cir |
cult and set the usual Morse recording |
apparatus in motion. After each signal |
has been received a little hammer taps |
the filings into their first position, and /
thus breaks up the current. This pro- !
cess is so slow that only about eight |
words a minute can be registered, and |
the slightest mechanical hitch is suf11-
Gent to set the whole apparatus at a /
The responder" Of De Forest is a
great improvement on this. A solu-
ton of caustfc potash is introduced in
to the receiving circuit, and when the
electric wave from the transmitting
station falls on it the solution is chem
ically decomposed, the resistance re-
duced, and the circuit bridged. Thus
the signal is recorded, and the moment
the wave has passed the liquid returns
to it's normal condition.
In receiving message, DR.. De Forest
does not rely upon the clumsy print
ing of the Morse apparatus. His ere
sponder'' is so sensitive that the oper-
ator is enabled to use an ordinary tele-
phone receiver to catch the click, click
of the incoming message.
The speed at which messages can
be sent rests on the ability of the oper-
ators alone. The usual rate a which
the Times reports are transmitted is
words a minute, but as
much as sixty words have been record
ed in this time. Messages are also be-
ing sent to the receiving station at !
Wei-hai-wei when the Hai-mun is $50 /
sea miles distant. while the Times cor
resnondent ranorts that transmitters L