t causes of fire.

The floors of such a mill were similar in their arrangement to those
of a dwelling. Joists connecting the beams supported the floor; and
the under side was covered over by sheathing or lath and plaster, thus
forming, as in the case of the roof, hollow spaces which were a source
of danger. This method caused at the same time an extravagant
distribution of material, by the prodigal use of lumber and the
unnecessary thickness of such floors, and entailed an excessive amount
of masonry in the walls.

Mills built after this manner were frequently in odd dimensions; and
the machinery was necessarily placed in diversified arrangement,
calling forth a similar degree of wasted skill as that used in making
a Chinese puzzle conform to its given boundaries. Their area depended
upon the topography of the site, and their height upon the owner's
pocket book. There was in Massachusetts a mill with ten floors, built
on land worth at that time ten cents or less per square foot, which
has been torn down and a new mill rebuilt in its place, because, since
the advent of modern mills, it has failed every owner by reason of the
excessive expenditure necessary for the distribution of power, for
supervision, and for the transfer of stock in process, in comparison
with the mills of their competitors, built with greater ground area
and less number of stories.

With the advent of the steam engine as prime mover in mills, and the
introduction of the turbine wheel with its trunk, affording greater
facilities in the application of water power, the character of these
buildings changed very materially, though still retaining many of
their old features. One of the first of these changes may be noticed
in the consideration which millwrights gave to the problem of fixing
upon the dimensions of a mill so as to arrange the machinery in the
most convenient manner. Although the floors were still hollow, there
was a better distribution of material, the joists being deeper, of
longer span, and resting upon the beams, thus avoiding the pernicious
method of wasting lumber, and guarding against fracture by tenoning
joists into the upper side of beams.

But this secondary type of mills was not honest in the matter of
design. The influence of architects who attempted effects not
accordant with or subservient to the practical use of the property is
apparent in such mills. The most frequent of these wooden efforts at
classic architecture was th