BEHAVIOR OF INDIVIDUAL STRUCTURES. 95 
without, however, producing any very large cracks. It is doubtful 
whether the wall is really safe in its present condition. On the inside 
of this building some of the wall columns were covered with 4 inches 
of brickwork projecting from the inner face of the wall as a pilaster. 
Some of these brick coverings had cracked almost entirely away from 
the main walls, besides being cracked vertically at other points in a 
manner similar to the cinder-concrete column coverings in the base- 
ment of the Aronson Building described on page 79. The brickwork 
in these places seemed to have been rather below the average in 
quality. It is not entirely certain whether the- fire or the earthquake 
caused the cracks, but all the columns seem to have been uninjured, 
although the brickwork of one or two was so badly damaged that it 
ought to be taken down and rebuilt. Some enameled bricks were 
practically ruined by the fire, which stripped off the enamel face 
(PL XL, -4). 
MILLS BUILDING. 
The large steel-frame Mills Building was without special bracing. 
The floors were of hollow tiles on the end-construction system, and the 
remainder of the fireproofing was likewise of hollow tiles. The tile 
arches lost their lower webs to a great extent, and some of them 
collapsed, apparently from heat alone; the column coverings failed 
very generally, and the girder coverings to a somewhat less extent 
(PI. XLV, B). One basement column buckled under the action of 
the heat (PL XL, B). The conditions in the Mills Building as to 
column coverings and partitions were similar to those in the Aronson 
Building. 
UNITED STATES MINT. 
The mint was an old-fashioned monumental structure with granite 
walls and segmental brick-arch floor construction, carried on iron 
beams. A general view, showing the southwest front, is presented in 
PI. XXXVIII, A, The building seems to have been practically 
uninjured by the earthquake, the only damage visible being at the 
base of the right-hand brick slack. It is probable that the shock at 
the locality of the mint was not so severe as it was at the new post-office 
building, although the two are only a few block's apart; yet the result 
may be an indication thai the solid old-fashioned monumental walls 
with the stonework solidly backed up by brickwork constitute after 
all one of the best types for resisting earthquake shocks. 
It is somewhat surprising thai the brick stacks were not over- 
thrown, but I am informed that the thickness of the masonry in these 
stacks was very great, which probably explains their stability. The 
northwest (PL XXXVIII. B) and northeast faces of the mint were 
