The Appeal. [volume] (Saint Paul, Minn. ;) 1889-19??, 1919-05-03
WAR INVENTIONS
COMING To LIGHT
Many Interesting Achievements
Are Now Being Made
Public.
SEAL OF silence BROKEN
System Of Sending and Receiving
Wireless Telephone Messages at
Same Time and 4 Barraqe Re-
celver Among Novelties.

ceIver Among Novelties.
New York.-As the seal placed upon
the activities Of Americas inventors
by the war Is broken, news Of many in
teresting achievements unknown to the
public during the conflict are being
brought to light. A system of sending
and receiving wireless telephone met
sages at the same time, as is done in
wire lines; ''barrage receiver" which
shuts out the sound Of all wireless VI
bration except those which the opera
tor wishes to hear, and a system Of
rapid and accurate photography of
wireless message became known to the
public for the first time recently, al
though government naval stations have
been experimenting with them for
some time.
Engineers Of the General Electric
company at Schenectady are RESPONSE
bic for each Of the inventions. Ernst
f. w. Alexanderson, consulting en-
gineer Of the company, told Of the de-
velopment Of the barrage receiver and
wireless telephony ideas at meeting
Of the Institute Of Radio Engineers at
20 West Thirty-ninth street recently.
G. A. Hoxie Of Schenectady, another
General Electric company engineer, is
the inventor Of the wireless photo
graphic apparatus.
Sending and Receiving.
Doctor Alexanderson told the engi-
neers that obviously some system Of
simultaneous sending and receiving
would have to be invented before wire
less telephony would ever become COM
mercially practicable. Switching from
one apparatus to another to send and
receive would be annoying and delay
ing. For instance, the user Of the tele-
phone on this side Of the Atlantic says:
"Hello" into the mouthpiece. Then
he has to switch to another apparatus
to catch the answer from Europe. And
perhaps his friend overseas is doing
the same thing, and the attempt at
conversation, develops into sort Of
hide-and-seek game. There was also
the problem Of bringing the wireless
telephone to the home Of the user. II
one has to travel to Washington or
New Brunswick to use the wireless tel
ephone 1t Is scarcely a saver Of time
or money.
Doctor Alexanderson has devised a
system Of separate sending and re-
ceiving antennae, the sending and re-
ceiving stations interconnected by
wire line and further connected to the
exchange Of the local telephone sys-
tenn, so that all Mrs. Jones has to do
when she wants to find out what Mr..
Jones is doing in Paris tonight is to
90 to her telephone and ask, not for
toll operator, but for the wireless op-
orator. he will connect her with Mr..
Jones.
Tho 6arrage Receiver.
The invention Of the barrage re-
ceiver came about as result Of the
confusion into which the wireless ma
chinery was thrown during the war.
Through her powerful stations at Nam
sen and elsewhere Germany was mali
ciously flooding the atmosphere with
wireless noise 80 that communica-
lions between France and England
and America became very difficult.
Germany was completely drowning out
the voice Of Americas allies. The in
terallied conference In February, 1918.
sought a way out Of the difficulty, and
appeals for solution were brought to
Doctor Alexanderson by Lieutenant
Paternot Of the French mission in this
country. The solution, which was
adopted by the French and American
governments after its first demonstra-
ton was called the "barrage receiver"
because the word "barrage" has the
original meaning Of stoppage proven
ton. The barrage receiver success
fulyl shut out the vibrations sent out
from Germany with the object Of de-
stroying the allied intercommunica-
ton. Its principle can be compared
to that Of an instrument which, If ap-
piled to the ear, would silence the
shrieking Of steam whistle ten yards
away, while enabling the listener to
hear perfectly the spoken word hun
dred yards off. Aside from its war
time use the barrage receiver has eI-
tensive possibilities for peacetime de-
velopment. Through it's use the num-
Der, Of communications that may be
carried on without disturbing each
other may be multiplied greatly.