REPRODUCED AT THE NATIONAL ARCHIVES
~Qe
Hence the increase in radiation after the “Able" shot relative to
cosmic ray background is twice that shown in the graph.
Vhile it is felt that the effect observed after "Able"
is real, the details of time dependence of the counting. rate can~
not be taken too seriously, owing to tho crudeness of the exper-
imental technique.
The tehavior of the counting rate after "Baker"
follows qualitatively the cosmic ray intensity pattern observed
by br. Scott Forbush at the Carnegle Institution in Yashingiion.
His lonization chamber was covered by a considerable quantity of
lead and would not he expected to respond to radiation of the
type piven off by fission products.
wburing this périod two othor
Ceiger counters were operated at some distance from the laboratory
by Lr. C.
7.
Raker.
His results showed the same reneral behavior
asa that shown in the g¢raph.
rom these obsorvations it would seem reasonable to
conclude that at a distance of 7000 miles tn the direction of
the prevailing winds it was possible to detect the effects of an
atomic bomb exploded in the air, but no effect from a similar
bomb exploded under water was observed.
J. ¥. bevire
October 25, 1946
STRATIVE MARKING
5, Section 6-10
4435, parogey i