Evening star., 1947-08-06
stors, Men and Atoms
Atomic Bomb Gas Looms
As New Terror of War
Explosives in Lake Near Cities Would
Clear Vast Areas
By Thomas r. Henry

Clear Vast Areas
By Thomas X. Henry
Atomic gas promises to join the atomic bomb
among the terrors of another war.
II would consist OF finely dispersed radio
active dust produced as q by-product of ths
manufacture Of plutonium in the great uranium
ovens such as are operated by the Government
at Oak Ridge, Tenn. and Hanford, Wash.
Such dust, which could be launched in the
same way as any other war gas, would be highly
lethal and might make q large area unin-
habitable for long time.
This is revealed in report by DR.. r. E.
Lapp Of the Research and Development Di-
vision of the General STAFF, which has just
been released by the War Department.
Cities Particularly Vulnerable.
In the same report it Is suggested that cities
besides lakes may be in particularly vulnerable
positions in case Of plutonium bomb attacks
If one wanted to kill of large numbers Of
the population and render the city unin-
habitable," says Dr. Lapp, lone might conceive
ably detonate the bomb in the nearby lake,
While no blast damage would be inflicted on
the city it might happen that the prevailing
winds would carry quantities Of spray-borne
radioactive materials over the city, thus rain
Ing down upon 1t lethal quantities Of invisible
radioactNity."
The size OF the atomic bomb remains the
most vital of all military secrets.
The basic requirement for its explosion Is to
bring together two masses of plutonium, each
too small to detonate spontaneously by itself,
into larger mass which is self-explosive Thus
size becomes factor Of the utmost significance
Increasing Bomb Size Complicated.
This has an immediate bearing on the per-
sistent rumors that there are bigger and better
bombs already available. Increasing the mass
would be-or perhaps has been-an extremely
complicated job, according to the report.
The bomb cannot be made larger merely by
increasing the size OF the two masses because
If either of them were any larger 1t would cease
to exist in fraction Of q second. The assump-
tion then IS, DR. Lapp explains, that If one
assumes that two subcritical masses Of pluto
mum are violently brought together then more
than two must likewise be brought together If
higher order Of explosion is desired. This
is more easily said than done"
The problem is far different than with TINT
or dynamite where the more the explosive
simply massed together the bigger the explo-
sion.
Problem Of Efficiency Raised.
Furthermore" says DR.. Lapp, there Is no
assurance that when one successfully detonates
such an improved atom bomb it will have the
same efficiency per pound of plutonium as Is
obtained with smaller bomb In view of the
scarcity Of this man-made element it must be
carefully rationed in peace and war.
These two factors, which are obvious to any
nuclear physicist, might alone limit the ulti-
mate feasible size Of atomic bombs, but there
is another even more convincing reason why
plutonium bombs may not be progressively
increased in destructive power. The reason Ia
that one of 20,000-ton high explosive blast does
not do as much direct damage as two 10000
ton explosions. This rule holds true for all
explosives