e of about five years this establishment was again put into
operation; but before the new mill could be safely filled with
machinery, it was necessary to remove all the beams which entered
walls and to substitute for them new ones, because the ends were so
thoroughly rotted that it would have been dangerous to impose any
further loads upon the floors. When floors are within a few feet of
the ground, unless the site be remarkably dry, it is essential to
provide for a circulation of air, which can be done very feasibly in a
textile mill by laying drain pipe through the upper part of the
underpinning, forming a number of holes leading into this space, and
then making a flue from this space to the picker room or any other
place requiring a large amount of air. The fans of the picker room,
drawing their supply from underneath the building, produce a
circulation of air which keeps the timber in good condition.

It is supposed by some that there is a difference in the quality of
timber according to the season in which it is felled, preference being
given to winter timber, on account of the greater amount of potash and
phosphoric acid which it is said to contain at that time. In some
parts of Europe it is a custom to specify that the lumber should have
been made from rafted timber, on account of the action of the water in
killing certain species of germs. Whatever may be the merits of either
of these two theories, the commercial lumber of the northern part of
this country is generally felled in winter and afterward rafted.

The action of lime in the preservation of wood has always been
attended with the most excellent results; although not suited to
places subject to the action of water, which dissolves the lime,
leaving the timber practically in its original condition. The
preservative action of lime upon wood is readily shown by the
admirable condition in which laths are always found. I doubt if any
one ever found a decayed lath in connection with plaster.

As an example of the action of lime as a preservative of lumber. I can
cite an instance of a mill in New Hampshire where the basement floor
was placed in 1856, the ledge in the cellar having been blasted out
for the purpose. The rock was very seamy, and abounded in water
issuing from springs or percolating from the canal supplying water to
the mill. The rock was blasted away to a grade two feet below the
floor, and most of the space filled up again by replacing the small