Evening star., 1935-02-09
STARS, MEN AND ATOMS
Notebook of Science Progress in Field.
Laboratory and Study.
BY THOMAS r. HENRY.

Discovery Of plant molecules large
enough to be seen with microscope
this is believed to be the first time
any molecule ever has been seen by
the human eye-was announced to-
day through the Office of the American
Association for the Advancement OF
Science here. 1t was reported from
the chemistry laboratory of the Uni
versity of Illinois.
A molecule is the smallest sub
division of a substance in which the
chemical properties are wholly re-
tanned. These particular ones have
molecular weight of 500 00000-that IS.
they are half million times heavier
than an atom Of hydrogen. They are
packed into the form of perfect
ellipsoid, the shape of an egg, and
always are found joined end to end
in chain fashion. They are one and
a half microns in length, a micron
being approximately four hundred
thousandths of an inch.
Botanists, according to the report
from DR.. George L. Clark Of the chem
istry staff. have been working on this
problem, in so far as cellulose and
plant products are concerned, for 81
years, but never have been able to
distinguish the fact that the real back
bone Of the structure of plants is this
little, uniform, crystalline particle
which is built up, in turn, from the
newly discovered giant molecules. The
reason for the failure before this, DR..
Clark says, has been that the mole
cules are embedded in some jellylike
substance which hitherto has not
yielded to any breaking down process.
The discovery is of special impor-
tance, according to the announcement,
because 1t lays the foundation for
possible synthetic rubber. Attempts
to synthesize rubber in the past
have not been very successful be-
cause the chemists, DR.. Clark says,
were working under the mistaken i'm
preston that the molecular weight of
rubber was $1,000. No product, rub
ber or otherwise, can be perfectly
made synthetically unless the exact
molecular weight is known.
Chemists have not been able to put
together a molecule of this size, but
now that 1t is known definitely that
they exist the next step will be to
produce them artificially. 1t will be
necessary to produce molecules eight
times the size of those now used in
producing synthetic rubber.
X \ X
One Of mans farthest reaches into
the region of the invisible and inf
nitely small-photograp the spec
ira Of chemical elements down to 49,
900 Angstrom units in the infra-red-
has just been reported by DR.. William
F. Meggers Of the Bureau Of Standards.
Each of the 80 chemical elements
has its distinctive spectrum. When
it is made to lun1inesce, it emits wave
lengths Of radiation specific to itself.
Each wave length it emits makes a
line in its spectrum and the spectrum
Of no two elements is exactly the
same. Each has some lines which
are not duplicated by any other. This,
in itself, affords a rapid and precise
means of chemical analysis, under
favorable conditions, which largely
has been developed in DR.. Meggers'
laboratory.
But the spectrum, in turn. depends
upon the structure of the atom of the
element-the number Of arrangement
of its electrons. Knowing the laws
which govern radiation emmission, the
physicists can reconstruct picture
of the atom itself-far as it is below
the utmost limit Of human visibility
from the lines of its spectrum. The
structure of these ultimate building
blocks of the universe, of which every