Evening star., 1940-05-30
Of Stors, Men
And Atoms
Notebook Of Science Progress
In Field. Laboratory
And Study
By Thomas r. Henry.

up on the campus of Johns Hopkins
University for the primary purpose Of
"aistilling" an appreciable amount Of
actino-uranium, the rare elemental
isotope, pound of which, it is believed,
would furnish more power than 25,oOO
tons of coal.
| The utmost secrecy is being observed
regarding details of the construction of
this apparatus which, if 1t works accord
Ing to expectation, may constitute step
toward changing the whole course of
human history.
It's giant tube-or battery of tubes
presumably is plated with gold on the
inside.
DR.. n. D. Fowler, Johns Hopkins chem
LIST who is in charge of the work, refused
to confirm or deny this.
1T certainly isn't lined with platinum"
| he said.
Platinum and gold, according to calcu-
lations hitherto advanced, are the only
Two substances which will hold the
deadly gas from which it is hoped to
extract Infinitely the most precious sub
stance on earth.
Asked If an extremely thin film OF gold
would be sufficient, DR.. Fowler said:
THAT depends on how carefully the
work is done"
A lew pinholes in the gold plating,
It Is admitted, would probably render
the apparatus worthless for this purpose.
Meanwhile, there are rumors, which
cannot be confirmed, that gold-lined
thermal diffusion tubes are being set up
at several other research laboratories.
The whole field of no-uranium ex-
traction is being kept in extreme secrecy
since the announcement a few weeks
ago that few almost invisibly minute
specks of the precious substance had
oeen obtained by means of the mass
spectroscope and the unverifable, but
persistent, report that Adolf Hitler had
turned over the Kaiser Wilhelm Insti-
tute In Berlin. world famous research
institution, for the sole purpose of OBJ
tanning an appreciable supply.
For more than year it has been rec.
orgnized that the German invented proc
ess OF thermal diffusion offered the only
practical means-unless Hitler's chem.
lists have hit on some brighter idea
tor obtaining an appreciable amount of
actlno-uranlum. 1t occurs in ordinary
uranium in ratio of ! part to l39.
The two are chemically indistinguish-
able, and hence cannot be separated by
any chemical means. Physically, how
ever, an actino-uranium atom is slightly
lighter than uranium atom and hence
any molecule of which it forms a part
is trifle lighter.
The thermal diffusion apparatus con-
sists OF tube heated to about 300 C.
Immersed IN a larger tube with bulbs
at the top and bottom. This larger tube
is kept at considerably lower tempera-
ture by means of constant water bath.
The large tube surrounding the smaller,
| heated tube is filled with gas. Eventually
| the molecules Of the gas rearrange them
| selves, the lighter rising to the top and
| becoming concentrated in the upper
| bulb.
There is only one form of gas in which
| uranium can be combined. This is
uranium hexifuoride, each molecule OF
which contains one atom of uranium
| and six of f1uorine. 1t is solid at room
temperature but turns into gas at about
| so degrees c. 1t is one of the most
caustic substances known to man.
So far as known at present only two
metals can hold it, gold and platinum.
While DR.. Fowler denied that his
tubes are lined with platinum and re-
fused to confirm that they are lined
with gold, it is hardly to be assumed that
some other substance has been found
that will hold uranium fluoride at the
high temperatures used in thermal
diffusion apparatus. Such a step would
be in itself major discovery. There
was hint of something of the sort in
brief communication from a University
| of Stockholm physicist to the British
| scientific journal Nature a few months
| ago. This, for whatever it is worth, NAV
| be in the possession of Kaiser Wilhelm
Institute physicists.
American physicists, while admitting
the sensational potentialities of actino-
uranium, consistently have secuted the
possibility of obtaining any appreciable
amounts of 1t for the present. Weeks
of work with the mass spectrograph pro-
duces less than a millionth of a gram
OF the precious substance, which hardly
suff1ces for experimental purposes. II
thermal diffusion works as well as It
promises to do theoretically, however,
the production would be limited only by
the availability of material and the size
Of the apparatus.
1t has been seriously suggested that
If the experiments of DR.. Fowler and
those of others reputed to be building
thermal diffusion apparatus work ac-
cording to theory, large part of the
gold held in storage at Fort Knox, Ky., be
released for gold-plating a superstill
which might turn out actino-uranium
at least by the ounce and possibly BY
the pound
In declining to give any details con-
corning his work DR.. Fowler stressed
that he has performed no diffusion ex-
periments as yet and has no assurance
that they will be successful. Early in
the theoretical discussion it was pointed
out that uranium hexihuoride is highly
unstable gas and there was no guarantee