Evening star., 1940-05-06
Chain Reaction Is Missing Key
U-235|s Atomic Power
But the Pioneer Who Storts 1t Probably Will
Live Only Long Enough to Describe Process
BY THOMAS r. HENRY.


BY THOMAS r. HENRY.
Within the last six months Ameri-
can physicists, using an apparatus
known as the mass spectograph,
have produced almost a millionth
OF an ounce of actino-uranium, also
known as U-235.
These microscopically minute
amounts. however, conceivably may
be the corner stones of a new civili-
zation.
Actino-uranium is. potentially, the
greatest source of energy known to
man, If present well-founded theo-
ries concerning it prove to be true.
Last week the Physical Review,
organ of the American Physical
Society, reported that about a mil
lonth of an ounce had been pro-
duced by DR.. Alfred o. C. Nier Of
the University of Minnesota. The
week before physicists of the Gen.
eral Electric Co., reported the same
accomplishment to the American
Physical Society meeting at the Bu-
reau of Standards. The potentiah-
ties Immediately became a matter
Of worldwide concern.
Germans Reported Hot on Trail.
For months past there has been
a persistent rumor-probable, but
naturally impossible to verify-that
Adolf Hitler has ordered all the re-
sources of the Kaiser Wilhelm In
stitute in Berlin turned over to solv-
ing the problem of large-scale sepa-
ration of the substance.
The Kaiser Wilhelm Institute is
one of the largest and best equipped
scientific institutions in the world.
On ts"staf are some Of the keenest
minds in the world. Out of 1t in the
last 80 years have come some of the
foremost scientific achievements of
all time. Maybe they know some
thing there which the rest of the
world does not know, including the
physicists of America.
If they succeed in separating this
substance to the extent of a few
pounds Germany may have in her
hands potentially the most terrible
weapon ever dreamed of-so much
more powerful than anything exist
ept today that comparisons are fan
tAstic.
Also it is practically certain that
the man who does the job will live
only long enough to tell how he did
it, and the whole staff of the Kaiser
Wilhelm Institute and lot of other
people living in the neighborhood
might die in few days. Super
powerful X-Rays, bombarding them,
would be impossible to escape.
Physicists Here Skeptical.
But meanwhile American physi-
cists are highly skeptical. Actino-
uranium is an isotope of the heaviest
of the 90 elements which is the
parent of radium. Physically the
nucleus of its atom is a trif1e lighter.
Chemically it is identical. During
the past year it has been found that
when actino-uranium is bombarded
with slow neutrons from a cyclotron
the nucleus of an atom which hap
pens to be hit breaks approximately
in halves. The neutrons and protons
in the nucleus of an atom are held
together by incomparably the vast
est forces in nature-something like
24,000, 600, ,000. .000, 900 times the force
of gravity acting between the same
masses. When an actino-uranium
nucleus splits 1t releases some Of this
force-a trifling 200, ,000, 900 volts Of
it. But this is vastly more than
anything ever yet known on earth.
1t is, presumably, the energy re-
sponsible for the heat of the stars.
One of the first demonstrations of
this fact was made at the terrestrial
magnetism labortary of the Carnegie
Institution of Washington a year
ago last January. e.
Now, of course, 1000, ,O00, 900 volts
has little meaning per sc. So far as
the breaking of a single atom Il
concerned it is the force behind
nothing. To hit single nucleus
billions of neutrons must be fired
AS Albert Einstein once expressed
it: It is like hunting ducks with
shotgun on a very dark night ir
country where there are very
few ducks.
/ Chain Reaction the Key.
Not only does the actino-uranium
atom split in two, however, but II
also shoots off some neutrons o.
its own In all directions. There.
fore, once the process was started
it is reasonable to suppose that Z
chain reaction might be set up, ont
atom exploding It's neighbors. II
that case the power obtained woult
be fantastically great. It is calcu-
lated that a pound Of actino-
uranium-it has the appearance o.
a black powder-would be equivalent
to approximately $4,000 tons Of Goa
or 10000 tons of gasoline.
But to date, it was explained today
at the terrestrial magnetism labora.
tory, nobody has ever actually dem.
onstrated such a chain reaction
There are various ways in which thu
neutrons produced by an exploding
atom might be dissipated without
exploding neighboring atoms. Ths
Washington physicists. under the di.
rection Of DR.. Merle A. Tuve Of TIN
Carnegie staf1, are not at ill con.
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