The morning news. [volume] (Savannah, Ga.) 1887-1900, 1899-10-27
MULTIPLEX TELEGRAPHY.
Sending Many Messages Over a SIM
gle Wire.
From the New York Tribune.

From the New York Tribune.
One of Edlson's greatest inventions is
the quadruplex system of telegraphy. He
has made it possible to send four mes
sages over a solitary wire simultaneously.
Two operators at the sending station can
dispatch messages together to the other
end Of the line-say from New York 10
Philadelphia-while two other operators at
the further station are successfully trans
hitting messages to the nearer one. Each
of the four messages can be switched off
to the right sounder and be put in writ
ing without confusion. The instruments
can be so adjusted as to accomplish their
selective action with perfect ease.
Prof Stephane Turpain of the School of
Medicine in Nantes, has devised plan
whereby Hertz waves, which are not the
same as the electric current used by Edi-
son, are made to perform the same work,
but on a larger scale. Hitherto the Hertz
wave has been employed in telegraphy
without wires. For a time Marconi had
only the ether for his medium of trans
mission. Since attaching a ground wire
TO his sending and receiving apparatus he
has added new route to the other. But
even so he has the solid earth, not a fila
ment OF metal, as his means of communi-
cation.
Here is another point OF difference be-
tween Marconis method and M. Turpain's.
At present, If the Italian wanted to con-
hne his communication 90 one recipient he
would place behind his transmitter a para
bonc mirror which would focus the Herlz
waves like the beam of searchlight and
project them upon the spot at which the
chosen station was situated Thus he
would exclude all other stations in his
neighborhood even though they had the
same sort of receiving apparatus as the
one with which he wished to hold con-
verse. There is another method by which
the sender can pick out a preferred sta
ton; but as yet Msrconi has not DEVELOPED
1t. He is perfectly familiar with the prin-
ciple, of course; but It is does not appear
that he has yet made any practical use
of II. II is this principle that NJ. Turpain
has employed.
Only a few days ago the Nantes profess
sor presented to the French Congress for
the Advancement of Science the results Of
his recent experiments with multiplex te-
iegraphy. To illustrate his plan he cited
an imaginary parallel in acoustics He
assumed that single tube was provided
at each end with several branches For
the sake of simplicity he made the mum.
Der of branches two. Then he imagined
that musical instrument having a GER
tain pitch emitted notes into the mouth
piece at the end Of one branch and an
other instrument with a different pitch
into the mouthpiece belonging to the other
branch. The two sounds would traverse
the tube without any Interference.
Arriving at the further end of the tube
they would be separated and made sensi-
bic In the following manner: Opposite one
of the branches at the receiving station
would be placed device-either A tuning
fork or something like it--which would vi
brate vigorously IN response TO the notes
entering the mouthpiece. The other branch
at the receiving station would be similar v
equipped with a tuning fork or other res.
onator that would answer only to The pitch
of the second instrument at the sending
station. Middle G on a pianoforte repre-
sents a given number of vibrations TO the
second. The above middle c requires
a larger number Of waves to the second
Musical resonators can be made TO re-
spond to any desired pitch. but wh1n once