The Saint Paul globe. (St. Paul, Minn.) 1896-1905, 1902-08-10
Morse or other signals transmitted
from the s4ndiiig station.
Col1Srerssand Decoherer.


"The receiver consists Of a coherer
ton the nature of which, wish to make
rev further remarks later) placed in
a circuit containing a local cell and
sensitive telegraph relay actuating an
other c1cuit, which works a trembler
OF decoherer, or recording instrument.
In It's normal condition the resistance
of the coherer-sis Infinite, or at least
very great,5and the current of the bat
terry cannot pass through it to actuate
the instruments, but When influenced
by electric waves the coherer becomes
a comparatively good conductor, it's
resistance falling to between 100 and
800 ohrns This allows the current
from the local cell to actuate the relay,
which in turn causes another stronger.
current to work the recording instru-
7ment and also the Taper or decoherer,
which is so arranged as to tap or shake
the coherer, and in this way restore
It's sensitiveness. The practical result
is that the circuit of the recording in
strument is closed for time equal to-
that during which the key is pressed at
the transmitting station, and in this
way 1T is possible to obtain graphic,
acoustic or optical reproduction of the
movements of the key at the sending
station. One end of the tube or CO.
herer is connected to earth and the
other to an insulated conductor, pref,
erably terminating in a capacity area
similar In every respect to the one en-
ployed at the transmitting station.
Transmissions up to 100 Miles.
Il notice that by employing similar
vertical rods at both stations it, was
possible to detect the effects of electric.
waves, and in that way convey the in
telllSent alphabetical signals over dis.
tanees far greater than had previously.
been believed possible, and by means
nf low.
transmission up to about 100 miles.
We're obtained.
1t Was soon, however. realized that
so long as it was possible to work only
two installations within what l may
call their sphere of influence a very
important limit to the practical untili--
cation of the system was imposed.
Without some practical method of
tuning the stations, it would have been
impossible to work number in the vi
entity of each other at the same time
without interference, caused by the
mixing of messages. The new methods
of connection which 1 adopted in 1898.
i. e., connecting the receiving Verti-
cal wire or aerial directly to earth in.
stead of the the coherer, and by the in
PRODUCTION of a proper form of oscilla-
ton transformer in conjunction with
condenser SOFAS to form a resona tor
tuned to respond best to waves given
out by a given length of aerial wire
were Important steps in the right di :.
rection. Is had, however, realized at
the time that one great difficulty in the!
way of achieving the desired effects
was caused blythe action of the trans
hitting wire. IA straight rod in which
electrical oscillations are set up, forms,
as is we'll known, very good radiator
of electrical waves. In all what we
call good radiators electrical oscilla-
|. tons set up by the ordinary spark
discharge method cease or are damped
out very rapidly, not necessarily by
resistance, but by electrical radiation,
removing the energy in the form of
electric waves.
1T is a Well-knoWn fact that when
one or two tuning forks, having the
same period of vibration, are set in
motion, waves will form in the air.
and the other tuning fork, if in suitable
proximity, will Immediately begin to
vibrate in unison with the first In
the same way violin player, sounding
a note on his instrument, will find re-
Spouse from a certain wire in a piano
near by, that particular wire, out of all
the wires in the piano, happening to be
the only one which has a period of
vibration identical with that of the
musical note sounded by the violfnist.