The Indianapolis journal., 1903-08-30
THE LATEST In WIRELESS
INVENTION To MAKE MESSAGES Ex-
elusive PROPERTY OF STATIONS.
Will Greatly Broaden the Field of
Wireless Te1egraphy by Making
It Available on Land.

BOSTON. Aug. 2s.-Mr. John Stone Stone.
lecturer in the electrical department OF the
Massachusetts, Institute OF Technology,
who Is well known for important inventions
IN the development of long-distance tele-
phoning. has recently proved the value OF
years OF work devoted 10 the commercial
aspects OF wireless telegraphy by sending
messages from Cambridge TO Lynn, Mass,
= distance OF about twelve miles, under
conditions that have hitherto been deemed
impossible. Until this message, no wire
less telegraph had been successfully Oper-
ated within three miles Of an electric car
line. or sent under conditions at all similar
10 those OF an ordinary tslegram-condi-
lions. however, that are absolutely essen
tial to reducing Hertz's great discovery to
the terms OF a matter-of-fact daily busi-
ness. Under the new system. in short,
wireless telegraphy becomes a means of
communication on land. where all the con-
ditions OF daily Ife-trolley cars, sky scrap
srs. thunderstorms and the ever-present
electrical disturbances presented by the
wires Of telegraph and telephone systems
already in operation-have so far made it
an impossibility. In the matter of large
surfaces OF water it's operation is, of course.
The new system. moreover. takes yet an
other important step in the direction of
making wireless telegraphy a universal
convenience. for il not only reduces the
height or the masts to practical proper
tions. but 1t has solved the problem Of MAX
Ing each message the exclusive property of
the sendipg and receiving stations. This is
essentially the experimental achievement
or the technology investigator; what use
VIII be made OF ii remains to be seen.
WHAT THE SYSTEM LACKED.
Some time before the actual success at
tanned by the operation of Mr. Stones ap-
paratus Prof. Louis Duncan head of the
electrical department OF the Massachusetts,
Institute Of Technology, with which insti-
tuition the latest American inventor is him
self connected as lecturer on the subjects
OF electrical oscillations and wireless teIeg-
raphy, summed up the situation after an
examination OF the preliminary laboratory
work then already accomplished. 1T has
beeo demonstrated said Professor Duncan,
thai with the present apparatus, ii is not
possible successfully to send and receive
selective signals; that is, signals which are
received by only one station to the exclusion
or all others. The commercial success of
wireless telegraphy depends upon develop
ing a system which is selective 1 believe
that the methods you have evolved are the
only practical methods which will accom-
plish this object. The experimental sta
tons you have erected have shown a selec-
tivity OF about 10 per cent. This have per-
sonally verified. Such a degree of selectiv-
ity is quite sufficient for commercial pur-
At ba Il
that your present apparatus. when put in
its ultimate and commercial form. will show
an even greater degree of selectivity."
In seeking to reduce wireless telegraphy
20 terms of everyday utility the problem
which Mr.. Stone has so far solved sue
cessfully is three-fold. Obviously in these
days no system Of wireless telegraphy could
become generally practical so long as it
could not be operated without disturbance
by trolley cars, telegraphs, or other cleo
trical methods of transportation or COM
munication. Nor could any such system
become altogether dependable so long as IL
necessitated the use OF poles so high that
they would De endangered by every big
storm or send out messages that were not
confined exclusively 10 the sending and re-
ceiving stations and could not be over
heard by the apparatus OF other stations.
To obviate the first OF these difficulties Mr..
Stone found method OF isolating his sta
tions from all surrounding electrical dis
turbances: TO obviate the second he has. so
10 speak, greatly increased the transmitting
efficiency OF small currents and at the
same time shortened the length OF his
mast; and TO overcome the third trouble he
has invented an apparatus so "selective"
that IL transmits a message that can be
neither received nor interfered with by the
instruments OF any other system
EXPERIMENTAL STATIONS.
Lacking the towering height of the Mar
conf masts. and lacking also the excite
ment OF the first discovery OF a great pos
sibility Of intercommunication, Mr.. Stones
two stations in the small desert of newly
male land between Boston and Cambridge
have attracted comparatively little atten-
tion during the sixteen months I'm which
preparations have been making for the first
wireless message between Lynn and Bos-
ton. An electric car line passes between
these stations and another within seventy
five feet OF the base OF the receiving wire
at Lynn. The Cambridge stations. sep
srated by about a third of a mile. were
equipped with forty-foot masts and with
means for developing. radiating and re-
ceiving electromagnetic signal waves of
different lengths at the will OF the opera
tor. II was found in practice. as had been
previously developed in theory by labora-
tory experiment. that signal waves differ
Ing In frequency by less than 10 per cent
could be easily picked out at the receiving
station and caused to operate one or the
other of the receiving aparatuses by a
proper adjustment OF the receiving cir
cults In other words as the different
sound waves, produced by correspondingly
different numbers OF vibrations of the tun-
Ing fork. produce sounds OF different in
tensity. the vital principle OF Mr.. Stone
selective apparatus may be roughly re-
duced 10 terms OF music. If you imagine
three boys standing within speaking dis
tance and two OF them capable OF dis
tinguishing a certain note In the vocal
scale that the other cannot distinguish. the
two boys are in the same mutual relation
rs the two stations or the Stone wireless
system. II you reduced that note to terms
OF the Morse alphabet the two boys would
have method OF communication OF which
the third would be ignorant. And II is by
scientifically selecting the wave length to
which only his own apparatus will respond
that Mr.. Stone has changed wireless teIeg-
raphy from a heller skelter sending of a