Evening star. [volume] (Washington, D.C.) 1854-1972, 1897-09-13
SYMPATHETIC TELEGRAPHY
Electric Waves Transmitted Without Con.
Meeting Wires.
Consul General De Kay Writes From
Berlin OF Recent Interesting
80. Experiments Abroad.

many. Some years ago." he says, EFF
forts were made, with but partial success,
| to telegraph without connecting wire from
| the mainland to an island by using the
sympathy that is shown by a wire buried
in the earth on the island when a charge
| of electricity was sent through similar
wire buried on the mainland. In some
cases. faint reactions were noted in the
| island wire, and it was hoped that by pass
ing and disseminating the charge through
one buried wire the ticks might be regis
| tered by the other, and thus a sympathetic
| telegraphy be perfected.
| Large sheets of copper were also tried
| in place of wire, also wires wound round
buried magnets; but IT was found that the
earth diffused the electricity so much that
nothing of practical value ensued Other
| experimenters considering the extraordi-
| nary resemblances between the action of
! electric waves and light waves through the
| air, sought for means to send electricity
| through the air itself. This has been ac-
| complished in England by Marconi, whose
| tame reached America some tire ago. Bat
| since 1t may be that no popular description
| Oh his method has been published ard
| since the experiments of Professor Rubens
| CT Frankfo1t instructor in electric physics
at the Berlin Polytechnic. have helped to
| make the method more precise, 1 venture
] to send the following report:
/ Marconi experimental from the British
mainland to an island four marine miles
| waves invented by the late Professor Her,
| which generator throws the waves of cleo
| tricity in all directions. as the rays OF light
| enanate on all sides from a flame.
| Concentrating the Rays.
| THE problem was to concentrate these
| rays or waves of electricity in one direc-
| ton, namely, toward the island. This he
did by placing a concave mirror behind the
Herr generator. by which the waves were
nd do roll al IN
| qrired direction. On the island he placed
| what is called 'coherer," that is to say,
| tube filed with particles of metal of Just
| the right size and quality for the purposes
| aow to be set forth. The cDherer was set
| before another concaye mirror. placed
| that 1t would catch the electric waves COM
| ing parallel across the water from the con-
| cave mirror and Herr generator on the
| mainland. The coherer was set exactly All
| the focus. Imagine that the Herr gener-
| atcr on the mainland is a flame whose light
| rays are caught by concaye mirror
| thrown over to the island, caught there in
| another concave mirror and focused on the
cCherer. Now, the metal particles in this
| &C herer are so adjusted as to size that the
| whole may be likened to violin string
| which vibrates when a certain sound is
| made by the voice.
| "As one can tune a violin string to a
| certain note, SO one can find the metal
| particles that will vibrate to an electric
wave of certain size. Try to pass an
1
ordinary times ana there will be no result
| but when the waves generated by the Herr
| generator, coming from d distance, fall on
these particles a vibration is set up in
| them, they touch each other. and chlrge
of electricity applied TO the tube is allowed
| to pass through and can be registered in
| the usual way.
| Thus, the coherer being supplied with
| an ordinary battery and Morse electro
| magnet. permits the circuit to be closed
| when the electric waves from the main
lhnd reach 1t. The click is registered only
| when the rays waves from the Herr
| generator are reflected on it,
s!'Ihe electric waves are not believed to
| be vibrations i'll the air itself, but rather in
me ether between the particles of air. As
compared to light waves, they are of en-
| ormous relative size. 1t will be noted that
| the electric cdrrent on the island sent
| through the eoherer has no other office
| than to stne5Ig.hen and register the effects
\ OF these waves or rays caught by the con-
| cave mirror and focused upon the cohcrer
| That the electric waves do in many
ways act like light rays, though they are
| much longer, 1 saw recently demonstrated
| In lecture / was permitted to attend at
the Polytechnicum in Charlottenburg- Ber-
| lin. To get some idea of the relative size
| of electric waves when compared with
| those of light, imagine that the light
| waves are represented by the width of the
Hudson river at New York city; then the
eiectric waves would be represented by the
| Atlantic ocean and Baltic sea, say from
| New York to St Petersburg
| "Or, to express it in sound waves. the
waves Of light are SO high and sharp, while
those OF electricity are long and deep,
| that the light waves may be compared TO
the highest, shrillest sound which the hui
| man ear can grasp, while those of elact,.i,i
~ are comparable to the deepest diapason
note of an organ.
German Experiments.
| THE lecture I allude to was one which
Prof. Rubens, young herman of Dutch
| Polytechnic, gave to number of teachers
Since Hers death in 1888, he said, much
| progress has been made in reducing the
| size of the electric-wave generator. As
| the size of the apparatus has relation to
| the length Of the electric waves, and as it
was desirable to shorten these waves the
| decreased size of the apparatus has been
OF use IN making air biography more prac-
| ticable. Shorter electric waves are more ap-
| proximate in their action to waves of light
| and go further. Up to the present, the
| shortest are those Of the Russian expert
| menter Lebedew, who has produced them
from six to seven millimeters long, Prof
Rubens showed a thermo element or heat
catcher, invented by himself to take the
place of Marconfs coherer, which catches,
| nke the coherer, the refracted and focused
electric rays. The spark. he observed, was
not at all a Necessary phenomenon in cleo
tricity. He then made many curious ex-
periments to show the similarity in ac-
l eAoAi "a WasCo VI ASuI anu waves OF cleo
tricity, and also drew attention to the
very different way in which electric and
nght waves pass through different sub
stances. Thus he reflected electric waves like
light, refracted them with prisms and
attracted them with a wire grating of
parallel wires. as light is diffracted by
Langiey,s grating. He then showed the
polarization OF these rays.freely. through
the ffbers Of wood longitudinally; and bad
~, across the fiber: easily, through closed
books with the leaves; and with difficulty.
across Thus. a pile of books or sheets OF
glass showed polarization like crystals UNI
der light He showed. Also that, on ac-
count of the length of these waves their
energy was absorbed differently by dit
ferent substances: thus a. water absorbs
all the energy. 90 metals absorb all the
energy. ca glass absorbs nearly ali. a.
paraf1ln absorbs hardly any, and (5) hard
rubber absorbs hardly any. Thus they
move through hard. black rubber and par
atm as light moves through air, glass or
water-that is to say, with hardly any re-
sistance-while glass lets very little of
them through. and metal and water are
impervious to them.
Prof. Rubens imbeds his Herr generator