696THE NATIONAL GEOGRAPHIC MAGAZINE
j
Photograph by Gilbert Grosvenor
SOMETIMES A PHOTOGRAPHER MUST TURN STEEPLE JACK
Richard H. Stewart, GEOGRAPHIC staff photographer with the strato
sphere expeditions, works on a lofty perch he built in a pine tree overlooking
the Stratobowl to obtain a comprehensive view of the camp.
of the flight, at
72,395 feet, there
was a decrease in the
number of recorded
rays.
WHERE COSMIC RAYS
ABOUND
At 40,000 feet the
rays from the vertical
were 40.1 times as
many as those re
corded from the ver
tical at sea level. On
the flight of Explorer
I, July 28, 1934, the
number found at 40,
000 feet was 42.3
times as many as
those found at sea
level. During the
flight of Dr. and Mrs.
Jean Piccard in the
autumn of 1934 it
was found that the
ratio at 53,000 feet
was 53.2; while dur
ing the flight of Ex
plorer II the ratio at
that same altitude
was 51.5.
At 57,000 feet, dur
ing the flight of Ex
plorer II, the vertical
rays were 55 times
those coming in at sea
level. This was the
maximum value re
corded. At 72,395
feet, the ceiling of the
flight, the number of
rays from the vertical
direction had fallen
to 42 times those at
sea level.
"We believe," says
Dr. Swann, "that the
explanation of this
phenomenon is to be
found in the assump
tion that many if not
nearly all of the rays
observed are what we
may call secondary
rays, shot out from
the atoms of the air
by the primary rays
entering from space.
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