sion also caused great damage to equipment
by tumbling and battering. Fires generally of secondary origin
consumed practically all combustible material, caused plaster to crack
off, burned all wooden trim, stair covering, wooden frames of wooden
suspended ceilings, beds, mattresses, and mats, and fused glass, ruined
all equipment not already destroyed by the blast, ruined all electrical
wiring, plumbing, and caused spalling of concrete columns and beams in
many of the rooms.

Almost without exception masonry buildings of either brick or stone
within the effective limits of the blast were severely damaged so that
most of them were flattened or reduced to rubble. The wreckage of a
church, approximately 1,800 feet east of X in Nagasaki, was one of the
few masonry buildings still recognizable and only portions of the walls
of this structure were left standing. These walls were extremely thick
(about 2 feet). The two domes of the church had reinforced concrete
frames and although they were toppled, they held together as units.

Practically every wooden building or building with timber frame within
2.0 miles of X was either completely destroyed or very seriously
damaged, and significant damage in Nagasaki resulted as far as 3 miles
from X. Nearly all such buildings collapsed and a very large number
were consumed by fire.

A reference to the various photographs depicting damage shows that
although most of the buildings within the effective limits of the blast
were totally destroyed or severely damaged, a large number of chimneys
even close to X were left standing, apparently uninjured by the
concussion. One explanation is that concrete chimneys are
approximately cylindrical in shape and consequently offer much less
wind resistance than flat surfaces such as buildings. Another
explanation is that since the cities were subject to typhoons the more
modern chimneys were probably designed to withstand winds of high
velocity. It is also probable that most of the recently constructed
chimneys as well as the more modern buildings were constructed to
withstand the acceleration of rather severe earthquakes. Since the
bombs were exploded high in the air, chimneys relatively close to X
were subjected to more of a downward than a lateral pressure, and
consequently the overturning moment was much less than might have been
anticipated.

Although the blast damaged many bridges to some extent, bridge damage
was on the whole sligh