ed the avarice of speculation, and,
when I saw it, was filled with workmen, who where converting it into a
tasteful mansion, adding wings to it, throwing out verandas, and
destroying every vestige of its original purpose. One of the workmen
shewed me the chamber in which, in 1774, the King and Queen took their
breakfast; while, in the room beneath, fires were lighted on the
floor, and various inflammable materials were ignited, to prove that
the rooms above were fire-proof. Marks of these experiments were still
visible on the charred boards. In like manner there still remained
charred surfaces on the landings of the staircase, whereon fires had
been ineffectually lighted for the purpose of consuming them, though
the stairs and all the floorings were of ordinary deal! The fires in
the rooms had been so strong that parts of the joists in the floor
above were charred, though the boards which lay upon them were in no
degree affected.

The alterations making at the moment enabled me to comprehend the
whole of Mr. Hartley's system. Parts of the floors having been taken
up, it appeared that they were double, and that his contrivance
consisted in interposing between the two boards, sheets of laminated
iron or copper. This metallic lining served to render the floor
air-tight, and thereby to intercept the ascent of the heated air; so
that, although the inferior boards were actually charred, the less
inflammable material of metal prevented the process of combustion from
taking place in the superior boards. These sheets of iron or copper,
for I found both metals in different places, were not thicker than
tinfoil or stout paper; yet, when interposed between the double set of
boards, and, deprived of air, they effectually stopt the progress of
the fire.

The House of Commons voted 2500_l._ to Mr. Hartley to defray the
expences of this building; the sovereign considered it a popular act
to give him countenance; and a patriotic lord-mayor and the
corporation of London, to impress the public with deeper convictions
of its importance, witnessed the indestructible property of the
structure on the 110th anniversary of the commencement of the great
fire of London. Yet the invention sunk into obscurity, and few records
remain of it except the pompous obelisk and the wreck of this house.

It merits observation, that in modern-built Houses taste or accident
has effected sufficient security against fires without any special
preventives. Fla