The record-union., 1899-04-16
WIRELESS TELEGRAPHY.

Wireless telegraphy is now established
as more than a theory. 1t has been ac-
complished in more than one part OF
the world, and is no longer a mere
fancy. 1t was made possible by the
discovery by Hertz, the German, Of
electric waves, and by the invention Of
a Frenchman, Brandy, of means-the
.'eoherer'-by which such waves may
be detected and registered. But the
chief credit is TO be given to Marconi,
an Italian, who in England brought
these discoveries within the realm Of
the practical sciences.
Here, then, we have Germany and
France discovering, Italy applying and
England becoming the seat of the de-
monstration of one of the greatest Won
ders of any time. Truly here is COS
mopolitanism, as the Literary Digest"
suggests, that in science is alone pos
'sible; for it has no politics, no national
traditions, no local or broad hatreds,
jealousies or enmities
But in France also we have had some
y.
Paris for the last few months the people
have been much puzzled who live in the
Rue Claude Bernard, by seeing a very
tall pole, indeed al great mast, rising far
above the house of NJ. Ducretet, the in
ventor and electrical student They are
now told that 1t is the first French in
strument Of actual telegraphy by cleo
trio waves and without wires; that the
period of these waves is $1,000 a second
less rapid than those of light, but capa-
Bile of transmission through space and
of being received by an apparatus at a
distance precisely as the waves of light
are received upon the retina of the eye
From the top of Ducretet's mast floats
in the air an insulated conductor, while
at the other end the mast commune
Gates with the pole of an induction
coil and one of the spheres of discharge.
The other pole of the coil is connected
with the other sphere and then WITH
the earth When an electric current
passes through the coil a discharge
takes place between the spheres which
constitute what is called the "osculla-
tor" Thus continuous discharges may
be effected, and these become the
sources of the electric waves. From
the masthead insulated conductor these
waves radiate. The extremity of this
conductor is fitted with a metallic sur
face that furnishes with the conductor
the requisite electric capacity SAYS the
translator of Ducretet's paper on the
subject.
This radiating conductor, therefore.
becomes the transmitter, and as by KEY
operation the discharges may be made
short or long, it is easy to understand
how a code of signals like the Morse al
phabet can be established and used. The
receiver is tube filed with metallic
filings. called a "coherer," or by Brandy
''radioconductor." On one side 1t rs
put into relation with an insulated con-
ductor floating at the head of another
tall mast On the other side it is re-
lated to the earth. The end of the in
sulated conductor collects the electric
waves.
The coherer is placed in the circuit of
a battery and a sensitive telegraphic
relay. battery current passes in the
electro magnet of the relay only when
electric. waves coming through space
traverse the ''coherer' and cause it to
become conductor. But its conduct
ability can. be destroyed by slight
shock, and so a. Taper operated by a
magnet. as in an electric bell, gives the
shock when the current passes. This
discontinuous conductivity is utilized
for ths collection Of the waves. The
translator continues:
As in all kinds of telegraphy, each
station must have both transmitting
ana receiving instruments. The mast
and its insulated conductor serve, by
The use OF commutator, SUCCESSFULLY
as transmitting radiator and as collect
Ing receiver of the waves A portable
receiving instrument suffices for the
reading of the Hertzian signals by
sound; by connecting it with register
ing apparatus the message may be
printed on band of paper. Such a
message may be said to fall from
heaven,
Experiments with these telegrapEic