d to the subject of fire-proof dwelling-houses of average
size, I consider that such houses when built of brick or stone, with
party-walls carried through the roof; the partitions of brick, the
stairs of slate or stone, the joists of wrought iron filled in with
concrete, and the whole well plastered, are practically fire-proof
because, as stated at the opening of this chapter, there is no
probability that the furniture and flooring in any one room would make
fire enough to communicate to another. The safest manner of heating
such houses is with open fire-places, the hearths not being laid upon
timber. Stone staircases, when much heated, will fracture from cold
water coming suddenly in contact with them; but in a dwelling-house
built as described above, there is very little chance of such a
circumstance endangering human life, even with wooden steps carried
upon brick walls, and rendered incombustible by a ceiling of an inch
and a quarter of good hair mortar and well pugged, all the purposes of
safety to human life would be attained.

There is a particular description of floor, which, although not
altogether fire-proof, is certainly (at least so far as I can judge),
almost practically so for dwelling-houses. It is composed simply of
plank two and a-half or three inches thick, so closely joined, and so
nicely fitted to the walls, as to be completely air-tight. Its
thickness and its property of being air-tight, will be easily observed
to be its only causes of safety. Although the apartment be on fire,
yet the time required to burn through the floor above or below, will
be so great, that the property may be removed from the other floors,
or, more probably, if the means of extinguishing fire be at hand, it
may be subdued before it can spread to any other apartment. The doors
must of course be made in proportion, and the partitions of brick or
stone.

Before closing the subject of fire-proof structures, I will add a few
words upon fire-proof safes. These are all constructed with double
casings of wrought iron, the interstices being in some filled with
non-combustible substances, such as pumice stone and Stourbridge clay,
and in others with metal tubes, that melt at a low temperature, and
allow a liquid contained in them to escape, and form steam round the
box, with the intention of preventing the heat from injuring the
contents. Such safes I have never found destroyed; and in some cases,
after large fires, the whole of the