falls, the air inside cannot escape sufficiently fast to avoid the walls of
the can being blown out again to some extent. These uncertainties are such
that estimates of pressure based on this method are on the low side, i.e.,
they are underestimated.

Another method of calculating the peak-pressure is through the bending of
steel flagpoles, or lightning conductors, away from the explosion. It is
possible to calculate the drag on a pole or rod in an airstream of a
certain density and velocity; by connecting this drag with the strength of
the pole in question, a determination of the pressure wave may be obtained.

Still another method of estimating the peak pressure is through the
overturning of memorial stones, of which there are a great quantity in
Japan. The dimensions of the stones can be used along with known data on
the pressure exerted by wind against flat surfaces, to calculate the
desired figure.



LONG RANGE BLAST DAMAGE


There was no consistency in the long range blast damage. Observers often
thought that they had found the limit, and then 2,000 feet farther away
would find further evidence of damage.

The most impressive long range damage was the collapse of some of the
barracks sheds at Kamigo, 23,000 feet south of X in Nagasaki. It was
remarkable to see some of the buildings intact to the last details,
including the roof and even the windows, and yet next to them a similar