age warehouse
in Boston, the fire doors are connected with the watchman's electric
clock system, so that all openings of fire doors are matters of record
on the dial sheet.

Fire doors should certainly be closed at times of fire; yet, that such
doors are open at night fires, or left open by fleeing help at day
fires, is an old story with underwriters. A simple automatic device
can be used to shut such doors. It consists of two round pieces of
wood with a scarfed joint held by a ferrule, forming a strut which is
placed on two pins, keeping the door open, as other sticks have long
since served like purposes.

The peculiarity of this arrangement is that the ferrule is not
homogeneous, but is made up of four segments of brass soldered
together with the alloy fusible at 163 degrees Fahr., which is widely
known for its use in automatic sprinklers. When the solder yields, the
rod cripples, and the door rolls down the inclined rail and shuts. At
any time the door can be closed by removing one end of the rod from
one of the pins and allowing it to hang from the other pin.

MILL TOWERS.

Because of economic reasons for preserving the space within the walls
of the mill so that it may be to the greatest extent available for the
best arrangement of machinery, the stairways should be placed outside
of the building. Such stairways should not be spiral stairways, but
should be made in short straight runs with square landings, because in
the spiral stairway the portion of the stairs near the center is of so
much steeper pitch that it renders them dangerous when the help are
crowding out of the mill.

The wear of stairs from the tread of many feet presents a difficult
problem. A very common practice consists in covering each tread with a
thin piece of cast iron marked with diagonal scores, and generally
showing the name of the mill. These treads wear out in the course of
time, but for this use they answer very well, although somewhat
slippery.

A wood tread gives a more secure foothold upon the stairway; and in
some instances stairs have been protected by covering the treads with
boards of hard wood, containing grooves about three-eighths of an inch
deep, and of similar width, with a space of half an inch between them.
These boards are grooved on both sides and placed on the stairs. After
the front edge is worn, they are turned around so as to present the
other edge to the front, and, in course of time, turned from the
exposed