r
spontaneous combustion, every opening, or crevice,
communicating with the external atmosphere to be closed.

An isolated staircase, of stone, or iron, well protected on
every side by brick, or stone walls, to be attached to every
story, and be furnished with a line of water-pipes,
communicating with the mains in the street, and ascending to
the top of the building.

In a range of stores, the different warehouses to be divided
by strong partition-walls, in no case less than eighteen
inches thick, and no more openings to be made than are
absolutely necessary for the admission of goods and light.

That the iron columns, beams, and brick arches be of
strength sufficient, not only to support a continuous dead
pressure, but to resist the force of impact to which they
are subject by the falling of heavy goods upon the floors.

That in order to prevent accident from the columns being
melted by intense heat in the event of fire in any of the
rooms, a current of cold air should be introduced into the
hollow of the columns, from an arched tunnel under the
floors.

There is no doubt that if the second principle could be carried out,
namely, the total exclusion of air, the fire would go out of itself;
but it seems, to say the least of it, very doubtful indeed if this can
be accomplished, and if it could, the carelessness of a porter leaving
open one of the doors or windows, would make the whole useless. The
fifth principle shows that Mr. Fairbairn has omitted to allow for the
loss of strength the iron may sustain from the increase of
temperature. The last principle would not be likely to answer its
purpose, even if it was possible to keep these tunnels and hollow
columns clear for a number of years, which is scarcely to be expected.
A piece of cast-iron pipe, one-and-a-half inch in diameter, was heated
for four minutes in a common forge, both ends being carefully kept
open to the atmosphere, when, on one end being fixed in a vice, and
the other pulled aside by the hand, it gave way.

One of the principal objections to the kind of fire-proof buildings
above described, is, that absolute perfection in their construction is
indispensable to their safety; whereas buildings of a more common
description are comparatively safe, although there may be some errors
or omissions in their construction. Indeed, Mr. Fairbairn states in
the