green. This autumnal appearance of the trees extended to about 8,000 feet
from X.

However, shrubs and small plants quite near the center of explosion in
Hiroshima, although stripped of leaves, had obviously not been killed.
Many were throwing out new buds when observers visited the city.

There are two other remarkable effects of the heat radiated from the bomb
explosion. The first of these is the manner in which heat roughened the
surface of polished granite, which retained its polish only where it was
shielded from the radiated heat travelling in straight lines from the
explosion. This roughening by radiated heat caused by the unequal
expansion of the constituent crystals of the stone; for granite crystals
the melting temperature is about 600 deg centigrade. Therefore the depth
of roughening and ultimate flaking of the granite surface indicated the
depth to which this temperature occurred and helped to determine the
average ground temperatures in the instant following the explosion. This
effect was noted for distances about 1 1/2 times as great in Nagasaki as in
Hiroshima.

The second remarkable effect was the bubbling of roof tile. The size of
the bubbles and their extent was proportional to their nearness to the
center of explosion and also depended on how squarely the tile itself was
faced toward the explosion. The distance ratio of this effect between
Nagasaki and Hiroshima was about the same as for the flaking of polished
granite.

Various other effects of the radiated heat were noted, including the
lightening of asphalt road surfaces in spots which had not been protected
from the radiated heat by any object such as that of a person walking along