Evening star., 1939-03-05
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Langmuir's announcement that he had meas
ured a film of oil, only one molecule in thick
ness, upon a solid surface. Remembering that
pigeon-holed experiment, Katharine Blodgett
now asked if she might not 60 further into the
subject.
A few months later, in February of 1884,
her first paper on the subject was published.
This was signed with her name only.
nit, in crisp sentences, terse as telegram,
she announced that she had spread upon glass
film of oil, not of the thickness of one mole
cule only, but that she had actually built layer
upon layer of molecules. one upon another.
More, she indicated, these layers rose from
the glass at an angle like field of wheat
stalks all bending the same way.
There, for all the world to see, if it had
the way to great discoveries. But no one took
the hint.
She went on with her patient, tireless
experimenting. Sixteen long months later, she
again published to the world, in a more
lengthy article, the results of her further
studies. This time, she disclosed that she had
been able to build up these invisible molecular
walls upon glass to a height of more than two
hundred layers. And she now noted the most
important observation of all the observa-
tion that the passage of light is affected by
these invisible films. She had been coating
glass slides with different thicknesses of molec-
ular layers. In short words she summed it up:
"A slide coated in steps shows bands of
vivid color when viewed by white light"
And she named, precisely the colors of the
first eight bands: yellow brown; dark blue;
light blue; yellow; red; blue; green; red
yellow"
That is to say unbelievable as it may SEEM,
she was giving commands to armies number
ing countless millions of molecules. making
them march and counter march, and build
themselves up in LAYERS, each layer at its GER
tain angle, until each close packed division
arrayed itself in uniform of distinctive color.
never varying. To any scientist working in the
field of optics, the hint of what might lie just
around the corner must have been breath
taking
She went on. The experimentation was
daily growing more and more fascinating. and
now DR.. Langmur himself joined her in it.
On March 20, 1887, they reviewed the work
of two more years, together. Now they spoke
of films that she had built up to thickness of
three thousand molecular layers. 1t was, of
course, the optical properties of such films
that now eagerly engaged their attention.
In the following June, Katharine Blodgett
was invited to address the Fourteenth Colloid
Symposium, a notable gathering of scientists
at Minneapolis. She spoke on The Properties
of Built Up Films of Barium Stearate. In this
paper she reviewed her continuing investiga-
tions of the optical properties of the films. But
there was still no hint of the possible applica-
ton of these properties as an aid to vision.
In this and in the preceding paper, another
miracle in her assemblages of the invisible
molecules was described. The many-layered
films, dipped in benzene, became skeleton"
films. The benzene dissolved the stearic acid
and left the barium stearate as skeleton,
with air filling the spaces previously occupied
by the stearic acid The film might then be
compared to boxful of glass bricks, each
brick suspended in air!
1t was comparison given me by DR..
(Confinvsd on poss 81