The daily star-mirror. (Moscow, Idaho) 1911-1939, 1921-12-19
SILENT DRAMA
THING OF PAST
Scientific Discovery at Illinois
University May RevOlutionize
Movie Industry.
RESULT OF YEARS OF STUDY
Professor Jakob kunz Develops an
Extremely Sensitive and Reliable
"Photo- electric Cell" Which
May Make Pictures Talk.

Urbana, Ill.-Will the moving pic
ture industry receive a revolutionary
addition through scientific discovery
made at the University OF Illinois,
basic patents for which are held by
that institution? 1t seems possible
that this discovery will make the mo-
vies of the future talk, so that there
will no longer be 1.-The silent drama"
The scientific discovery is that Of
an extremely sensitive and reliable
"photo-electric CELL" made about two
years ago in the physical laboratories
of the university by Prof. Jakob Kunz.
The incident is a good example of the
unexpectedness by which some great
discovery may be made years in ad-
vance of its possible practical use.
The photo-electric cell is device
for turning flashes of light into cleo
trio pulses and is so sensitive that it
reacts to light from stars which can
not be seen with the naked eye. Be
cause of this extreme sensitiveness the
photo-electric cell promises to displace
the selenium cell which has been used
up to the present time in experiments
carried on to produce speech to accom-
panying moving pictures.
Better Than Swedish Device.
A Swedish scientist has developed
q device which he calls the "phOto-
phone" by which such speech is more
or less perfectly produced This is
done by having second film on the
hn
film, on which are photographed va
rious curves and openings correspond
ing to the words which are to accom-
pany the pictures. A beam of light
sent through this film falls upon
selenium cell. The selenium cell de-
ponds upon a discovery made many
years ago that the metal selenium
changes its electric resistance when
light falls upon it. 1t is thus posi-
BILE to get variations in an electric
current by letting the beam of light
from a speech photograph film fall
upon such a cell. These variations
act in telephone to reproduce speech.
The selenium cell is much inferior
to Doctor Kunz' ph0to-electric cell
in transforming light waves into cleo
trio pulses. The photo-electric cell is
not only much more sensitive, but it
has no lag; that is, it responds imme-
diately to light wave even after
hours and days of use. The selenium
cell is not only not as sensitive but
it has the disadvantage Of having
this lag or fatigue.
Result OF Years of Work.
doctor Kunz has been working for
several years on the effect OF light on
certain of the alkali metals such as
and sodium" said the head |
Of the department "a layer of any |
one of these metals when in a vacuum |
off negative electricity; that is, cur
rent of electricity can be produced by /
citing a beam Of light fall upon a
1lm of potassium which is properly |
inside of an exhausted glass
)ulb The current passes across the
evacuated space to a loop of plati-
lum wire and thus to the outside cir
.uit. While this electric current is
rery small it can be amplified by
Methods which are well known today (,
n electro-technics and so the size
# the current Is no detriment to the
Ise of the photO-electric cell.
"Just as the little currents, which
we're set up at Arlington cemetery
N Armistice day by President Hard
ng's voice were magnified and repro
uced thousands of miles away, so
an these little photO-electric currents
e magnified and produce sounds in .
telephones" .
1t is therefore logical to expect that 4.
he scientific discovery of sensitive
nd reliable photo-electric cell will be
sed to give us the perfect photo
hone Of the future. One large COM 7
any is said to be already developing
UGH a use Of this photo-electric cell. T