Great Falls tribune. [volume] (Great Falls, Mont.) 1921-current, 1922-09-03
By H. GERNSBACK


WOttuu fSo"
CHEMES on television are
~ not new. Inventors have
~ busted themselves 70 I
several generations with this
invention, but so far nothing
of note has been produced.
The writer, in the May and
June, 1918, issues of the
electrical Experimenter" dis
cussed various ideas on tele-
vision and showed what had
been proposed by inventors
Heretofore. There are many
patents in existence referring
to the telephot (tele-far;
photos-light), but so far
there has been no inventor
who actually has been able to
demonstrate a continuous
view by electricity of a moving
object at a distance.
1t is not that it has been
impossible to do this, but the
great cost of such an appa-
ratus has been prohibitive.
Furthermore, one of the great
est stumbling blocks is that in
nearly all schemes shown in the past,
it was necessary to have hundreds and
even thousands of wires between the
sender and the receiver. If, for in
stance. we wish to talk to our friend
500 miles away over the wire all we
need is q single wire, Or two at the
most, if we do not wish to use a
ground or return circuit. If with the
schemes proposed heretofore, we
wished TO sec our friend at a dis
lance, it meant that we would have
had to string several hundred wires
between the two points and the idea
for this reason becomes at once i'm
practicable.
Scheme Has Possibilities
The author in this article proposes
a somewhat more ambitious scheme of
television. not only over wired lines,
but by radio. He wishes to state in
advance that no apparatus has been as
yet constructed along this line. but 1t
is believed that the scheme here shown
has possibilities that would seem invit-
ing to our constructors who wish to
take the time and trouble to build such
an apparatus. Engineers are of the
opinion that an apparatus of this kInd
will actually do the work with perhaps
a few minor improvements
The stumbling block with former
telephots or televisien schemes usually
was found in the selenium cell. This
was for the following reasons: When
we desire to project a picture at a dis
lance, it is first necessary that we
have some instrumentality which
changes the intensity of the electric
current in the same ratio as the lnten-
sity of the light that calls upon the in
strument changes. A picture, as is
well known. is made up of various
points. Pick out any half-tone illus
tration, view it under a magnifying
glass, and you will see that it is made
up of light and dark dots. The dark
dots give the picture it's dark tones and
the light dots give the half-toneS and
the white paper shades into unison with
the dots.
The selenium cell has long been
thought the best instrument to trans
late changes in the intensity of light
into electrical current impulses. Imag
inc a screen made up of several thou
sand selenium cells. A picture falling
upon this screen will thereby resolve
itself into the various c%omponents of
the picture itself. Then some selenium
cells will receive more light and others
less. d
Radio Overcomes Difficulties
The electrical impulses are hen sent
out over the wires to be reconstructed
later into a picture at the receiver. The
.-&,LIa x-.4L Al z-Js~ Ill =. laxry
ever, that it is sluggish. In other
words, the selenium cell takes a large
fraction of a second in which to change
its resistance. Light is instantaneous,
and reconstructed selenium pictures
are always tagging behind; if we ac-
tually could obtain a reconstructed pic
ture. it would be imperfect.
This trouble is done away with in
the authors radio television scheme.
whereby, instead of the selenium cell
we make use of photo-electric cells.
There have been lately developed a
number of such cells. which are avail
able and which are highly light-sensi-
tive. Moreover, they are not sluggish
in action as are selenium cells. In
other words. they vary their resistance
almost instantly as the light falls upon
them or as it is removed.
Referring to our main illustration.
the authors scheme resolves itself into
the following: At the transmitter we
have an ordinary camera-like box, in
the back of which we have a great
number of tiny phOto-electric cells.
Each cell responds according to the
strength of light and shade. The lens
in front of the camera picks up the
view and throws it inverted upon the
group of photo electric cells in the rear.
All dark spots Of the picture, as for