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UNITED statis DEPARTMENT OF COMMERCE
WEATHER suURZAY
WASHINGTON
Septempoer €2,19460
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Dr. Charles Dunham
Directcr, Division of Blology
and Medicine
U.Ss Atomic Mmergy Commission
BEST COPY AVAILABLE
Washington 25, D. Ca
Dear Dr. Dunham,
In attempting to appreciate the possible reasons for the presence of
Tungsten-185 in the equatorial stratosphere long after the Hardt&ack
test series, I have suggested, out not seriously, that the Tungsten
fe attached to Larger parti:ies than has been characteristic of
previous test series in tne Pa.ific. The prime difference, as far as
I am aware, detween the Hardtack testa and earlier ones, besides the
productica of Tungsten-155, {ts the loading of non-indigémeous sand on
those events in barges.
I have no information which would, at this
time prove that tie particle aize snouid be larger than in earlier
teats even if the Hardtack sand loading were unique. If the latter
were the case, it might Justify further search to see if the particle
size is influenced by the weapon environment. Thus, for the above
and probably other reasons, it would be highly deairable to obtain
information on the environment of ali of the muclear detonationa in
the Pacific.Proving Grounds.
We should like to have the kind of substances and their amounts given
in tre listing:
Very smail amounts of material in the weapon whicn
are highly eensitive data need not be provided.
In addition, ve
should appreciate a listing of the water depth for al) eititmwater
shots. While it would be desirable to obtain this date on an unclassified
basis, we would be willing to accept it as classified information.
Sincerely yours,
Leatar Machta
a)
Chief, Special Projects Section
Office of Meteorological Research
C ckoecere (1)
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