Evening star., 1923-04-01
RADIO LAMP MAY BE USED
AS CIVILIZATION SYMBOL

ing only one electrode. the lighting fila
I ment an English scientist in 1905 con-
ceived the thermionic valve or vacuum %
| tube, containing two electrodes, fla
ment and also plate" for use as a
rectifier of alternating current and
| hence a detector of radio waves.
J Three-Electrode Vacuum Tube.
| Two years later an American scien-
\ tist conceived the modern audion, or
! three electrode vacuum tube, containing
a lighting or heating filament, plate
and also grid" the latter comprising
| a controlling electrode," which, when
| properly manipulated electrically in
| conjunction with the filament and the
plate. will effectually control the ac-
! tionS of the invisible electrons within
| the tube, the flow of electric current
| into and through the tube for detection
| of signals and amplifying their strength.
| and the flow of electric current out Of
; the tube for the creation of ether or
| radio waves for transmission purposes
and the creation of electric currents
! for long distance land wire telephony
| and for almost innumerable other pur-
poses.
| 1t was the insertion of this third elec-
trode, or grid into the vacuum tube
! that transformed the device into one OF
untold value in radio and also in land
J wire telephony
1t not only perfected the tube as a
| very sensitive detector of radio waves,
comprising, as It does, the most sensi-
! tive radio detector in existence today,
but 1t also provided an instrument for
! effectually amplifying the strength of
! incoming signals, thereby enabling sig
| rails to be made audible which otherwise
would be inaudible, and making signals
extremely loud and easily intclligible
| which otherwise would be so weak as
! TO be unintelligible, although they might
! be heard family.
| The outstanding advantage in radio
| of the three -eleC1rode vacuum tube,
/ however, is the facility with which II
can be adapted to radio telephony. 1t
! is the one device that has made posi-
! bic the popular broadcast service of to-
| day, whose programs bring valua Bile in
| formation and advice, lectures. music
! and various forms Of Hholesome enter
/ talnment and amusement directly into
| hundreds of thousands of homes.
! whether in the cities, the towns, the
! villages, to isolated farms and ranches.
to lighthouses situated along the bleak
stretches Of our coasts, and even to
shins on the high seas.
The tube has already revolution
! lied the art of long distance land
| wire telephony. as ii is rapidly revo-
/ lutionizinG radio. by amplifyins
| through one or more repeater sta
: LIonS" the voice currents on the tele-
! phone wires. thereby enabling salts
! factory land wire telephone conver-
! Sations to be exchanged between
/ such widely separated cities as New
! York and San Francisco, or New York
! and Havana, Cuba. for example.
! The vacuum tube and electrons
constitute absorbingly interesting G
| subjects of study and speculation for
/ the radio man and the radio fan.
| From the advent of primitive man
up to the time of the invention by
Edison of the electric lamp there
stretches an undeterminable number
/ of centuries during which the torch
. representing both heat and light. and
+ Symbolizing science and human
knowledge. has constituted the guild
I ing, spirit of the material world.
We are now on the threshold of an
age wherein the electric lamp is like
+ ly to displace the torch for practical
heating and lighting purposes. and
especially as the symbol of progress
/ and civilization.
Copyrighted. 1923. 2lst Century Pressl