The Indianapolis journal., 1903-08-30

lie school experience. sets in action a series
OF waves, and II these waves cross room
containing a harp or piano the single string
that is in tune with the fork will vibrate in
unison. No other string OF the instrument
will be affected. Now. electromagnetic
waves have the same property. II the cleo
trical equilibrium of any electrical conduct
or as. for example, the vertical wire of the
tall mast Of a wireless telegraph station, is
abruptly disturbed and the conductor then
left to itself. electrical currents will flow
in it tending eventually to establish its
original equilibrium. These currents send
out into space electromagnetic waves ex-
actly corresponding TO them in frequence,
now translated into wave lengths and NOV
ing at about the speed Of a flash of light.
The new discovery simply goes long step
further than the old in controlling the
length of each wave sent out from its
transmitting station, and thus making it
impossible. as in the case of the tuning
fork and the piano. for any apparatus to
respond to it unless it has been so arranged
that il responds naturally TO just that num-
Der of vibrations per second.
The apparatus of Mr.. Stones wireless
system consists, therefore, of the familiar
mast, carrying the vertical conductor. and
the equally familiar apparatus for giving
the signal But between these pieces OF
apparatus is a third device that transforms
the original signal into certain regular pc
riods OF electrical disturbance. and these in
turn pass from the vertical conductor of
into space in electromagnetic waves of a
known frequency. These waves, passing
through space, will produce an electrical
disturbance only in an electrical circuit so
arranged that 1t responds naturally to this
artihcially established frequency, it's re-
sponse producing an exactly similar elec-
tricaI disturbance and this in turn repro
ducing the original message. The message
is therefore the exclusive property of the
two stations whose respective apparatus is
thus in harmony nor-what is equally i'm
portant-can either of these sets of appa-
| ratus be affected by waves of any other
degree of frequency that is, by messages
not intended for them.
Low MASTS SUFFICIENT.
For the recent successful signaling be-
tween Boston and Lynn 1OO-foot mast was
erected at the Cambridge transmitting sta
tion and mast some six feet shorter at
the Lynn receiving station. The Lynn sta
tion is almost completely surrounded by
| houses and the "air line" traverses the fac
tory part of Cambridge, the city of Charles
town. several other intervening cities, and
finally a considerable portion of the famous
| old shoe town in which the receiving station
is located. The line is therefore typical Of
one in actual commercial operation, run
ming from one section to another in much
the same fashion as a modern telegraph line
and thus doing away with the very high
masts not only expensive to erect, but al
| ways liable TO destruction by the elements
| now necessary to establish wireless COM
| munication over long distances. 1t Is the
plan OF the inventor TO have a series Of
these stations, say fifty miles apart so as
to transmit a long distance message from
one to another until 1t Is finally taken at
| its destination, and also to send and re-
| ceive local dispatches at each station. In
be Indispensable For the through mes
sages." however, Mr.. Stone has devised a
new method of relaying, or automatically
| repeating. the original message from one
station TO the next, and this message makes
| 1t possible apparently to telegraph overland
to practically unlimited distances. Sending
| a message by flfty-Tnile repetitions is not
| indeed so sensational an exploit as the wire
less message said to have been received on
the liner Philadelphia over 1851 miles Of
| restless ocean, but it is generally admitted
| that it is on the side OF land communication
| that the discovery of wireless telegraphy
| has its greatest sphere of probable useful
ness; and 1t is also admittedly more difficult
| TO operate over land than over sea-