Evening star., 1938-12-27
New varnish Makes
Glass Transparent
And Invisible
AboIishes Reflection
Of Light, Transmits
More Than 99%
BY the Associated Press.

BY the Associated Press.
SCHENECTADY, N. Y, Dec. 81
A varnish which makes glass invis-
ible and as transparent as air was
announced today by DR.. Katharine
B. Blodgett, noted woman scientist.
Colorless and thinner than wave
length of light, the film offers in
dustry new wonderland in the use
of glass. It can be used on all kinds
of glass, and it does two things
never before possible.
First, it abolishes all reflection Of
light, from any angle and from any
degree of glare. Second. 1t enables
glass to transmit more than 80 per
cent of the light. The best un-
treated glass passes only 80 per cent.
The lost 8 per cent is equivalent
to a dim haze, which has been un-
noticed because human eyes have
not previously had chance to make
comparisons.
Not Ready for Commercial Use.
The discovery is an amazing ex-
ample of search for scientific truth
with no conceivable practical value
being converted into something of
great artistic and commercial pos
Sibilities.
DR.. Blodgett, of the General Elec-
trio Co s research laboratories. made
this conversion. The discovery is
not ready for commercial use and
the chemical formula of the magic
film has not been publicized.
The seemingly impractical new
fact of science was discovered by DR..
Irving Langmuir, General Electric's
Nobel Prize winner in chemistry,
that oily substances will spread on
water in films the thickness of only
a single molecule.
Thinnest Film Ever Made.
This fact was used by DR.. Blodgett
to lay on glass probably the thin
nest film ever made by man. When
glass is dipped in one of DR.. Lang
muir's single-molecule layers, the
film transfers to the surface of the
solid.
BY dipping A times DR.. Blodgett
gets a film about 4millionths OF an
inch thick. This is about one
quarter of a wave length of light.
Light bends slightly as it passes
into the film. When it tries to re-
fleet from the glass, the reflected
wave runs into peculiar case OF
the wave motion OF light.
A quarter-wave-length OF lncom-
ing light meets a quarter-Wave OF
rejecting light in such a position
that the trough" of one wave meets
the crest" of the other. In wave
motion that means the end OF the
wave. This cancels the reflected
light, and all the light that would
have been reflected goes on through
the glass,
Filmed on Both Sides.
The glass has to be filmed on
both sides. An ordinary pane seems
to disappear, except for a faint
trace of it's edges. The edge vlsl-
bility is due to the fact that the
glass itself absorbs a fraction OF
l per cent of the light.
In the laboratory, glass over dials,
pictures, miniature showcases and
miniature windows cannot be seen
at all, except as a speck of dust may
reveal its position. 1t is said that
eyeglasses can be freed from all an
moving reflection. Cameras, which
lose 8 per cert of the light for each
lens, will, depending on the number
of lenses, transmit from 8 to 80
per cent more light to the negative.
In some periscopes the light will be
increased IS per cent.
Telescopes. using numerous lenses
and prisms. will give much clearer
view of the depths of space.