Evening star. [volume] (Washington, D.C.) 1854-1972, 1904-04-16
How Electrical Energy is Obtained

the new system is obtained from a two
horse power dynamo. a quarter-horse power
being used for the sending and receiving
of messages. and the remainder of the
power to light the office and building OF
the company.
Other business has detained Prof Fessen-
den in New York. and it has been only In
the last day or two that he has resumed
work here. Yesterday he mad a force OF
men, under the direction of Mr.. Globetz
one OF his assistants. adjusting the wires
leading from the crosS-arm to the ground
and preparing them to catch the sound
waves from Philadelphia, Signals have
several times been exchanged between this
station and those north. but as yet no
word messages have been sent or received
The national lawn akers did not know II,
of course but these signals. II is claimed.
passed directly through the Capitol build
ing it being directly In the air path along
which the signals travelled
Prof Fessenden states that between his
stations at Philadelphia and New York
messages are sent daily. irrespective Of the
weather. and that during the recent storms
the coast. when the wire system was
ceived with ease. Tests made during the
last eight months. he says. show that out
of 1000 messages of twenty-five words
each. only fourteen words had to be re-
peated.
Features Of the System.
The distinguishing feature of the system
to be used here is a liquid barreter or re-
ceiver. invented by Prof Fessenden, said to
be the most sensitive of any yet produced.
BY means of 1t the Morse system is en-
ployed, it Is claimed, without limit as TO
speed. and it is also claimed that the serv-
ice between Philadelphia and Jersey City
is maintained with an expenditure OF cleo
trical energy less than that required TO
Hph single inca DHeSce.at la
1t is claimed that the Fessenden receiver
has revolutionized the art of wireless teleg-
raphy, as evidenced by the results I'm the
transmission of news Of the war in the far
ecSt.
Prior to Fessenden's experiments the re-
ceiver in common use was the so-ca lied
coherer-a small glass tube with leading-in
wires sealed into the glass.
In practice this coherer has, Il is said,
been found to be erratic I'm its behavior.
sometimes working almost perfectly and at
other times for no apparent reason working
very poorly not at all.
After making a great number of quanti-
tative measurements Prof. Fessenden
thought it might be possible to abandon the
coherer and advise other methods of receiv-
ing signals based on the action of electro
cal currents instead Of electrical pressure.
The practical results obtained with a de-
vice constructed on the motor principle led
him to attempt to apply the same principles
to another physical phenomenon-that OF
by the heating effect of currents. He found
that small wire used bolometer could
be considered as n acknowledgements engine
and that its efficiency increased at very
much more rapid rate as Its diameter de-
creased than lad before been supposed. He
says he was able finally To devise a means
whereby platinum wire. coated heavily with
silver and then drawn down. could be so
manipulated to form receiver having
the desired characteristics and dimensions.
Natal nienouarad
BY removing the silver coating he pro-
duced a sensitive strip, whose mass was
something less than one-5ilIionth of a cubic
inch. This was termed by Prof. Fessenden
a metal barreter. and was patented. This
device. he claims, was in one sense almost
too much of a success. for its mass was SO
extraordinarily small that an electric spark
anywhere in the neighborhood however
feeble. was likely to burn 1t out unless pro-
tected by electrical tuning. This almost
invislbly fine platinum wire proved Indirect
ly the key TO the invention of the liquid
receiver.
Prof. Fessenden claims that IL the delicate
platinum loop Of the metal barreter was
broken. frequently happened. while i'm
mersed in the nitric acid used for dissolving
the silver. IL would. while the broken ends
projected into the acid act a receiver
even more efficiently than before Ii was
broken. He concluded that the result was
cue 10 the 1act tbat the small quantity OF
liquid Immediately surrounding the wire be-
came heated by the passage of the elect ical
currents produced By the electromagnetic
waves, and so decreased locally in resist
ance. He was led. therefore. he says, to
make the platinum wire conductor to
lead the current into or out of the conduct
ing liquid and to lead the current to an ex-
trcmely minute cross-section OF that liquid
The liquid and fine wire In combination
proved to be more sensitive than the fine
wire alone, and ordinary current could
burn the wire out because the liquid kept
It comparatively cool.