The daily star-mirror. (Moscow, Idaho) 1911-1939, 1921-12-29
SILENT DRAMA
THING OF PAST
Scientific Discovery at Illinois
University May RevoIutionize
Movie Industry.
RESULT OF YEARS OF STUDY
Professor Jakob Kunz Develops an
Extremely Sensitive and Reliable
"Photo-eectrc 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
gears ago in the physical laboratories
of the university by Prof. Jakob Kunz.
The incident is good example of thu
unexpectedness by which some great
discovery may be made years In adj
vance of it's 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 10 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
a device which he calls the photo
phone" by which such speech is more
or less perfectly produced This is
done by having a second film on the
same spindle as the moving picture
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 a
selenium cell. The selenium cell de-
ponds upon 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 a telephone to reproduce speech
The selenium cell is much inferior
to Doctor Kunz' photo-electric cell
in transforming light waves into elec-
trio pulses. The photo-electric cell is 4
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
Of the department. "a layer of any
one of these metals when in vacuum
or certain low pressure gases gives
off negative electricity; that is, cur
rent of electricity can be produced by
letting a beam of light fall upon a
film of potassium which is properly |
inside of an exhausted glass
evacuated space to loop of plati-
mum wire and thus to the outside cir |
cult. While this electric current is
very small, it can be amplified by |
which are well known today !!
in electro-technics, and so the size
Of the current Is no detriment to the |
use of the phOtO-electric cell.
"Just as the little currents, which |
were set up at Arlington cemetery |
on Armistice day by President Hard
ing's voice were magnified and repro
duced thousands of miles away, so |
can these little phOtO-electric currents
be magnif1ed and produce sounds in
Ioud-speaking telephones"
1t is therefore logical to expect that
the scientific discovery Of a sensitive
and reliable photo-electric cell will be
Used to give US the perfect photo
phone Of the future. One large COM
)any is said to be already developing
such use OF this photo-electric cell.