randeur. But the splendid exterior of the amphitheatre was not in
harmony with the bare and naked walls of the interior; there were none of
those durable and grand seats of marble, such as adorn the amphitheatre
of Verona, from which it is probable that the whole of the arena and
conveniences for the spectators had been constructed of wood. Their
total disappearance led us to reflect upon the causes of the destruction
of so many of the works of the older nations. I said, in our
metaphysical abstractions, we refer the changes, the destruction of
material forms, to time, but there must be physical laws in Nature by
which they are produced; and I begged our new friend to give us some
ideas on this subject in his character of chemical philosopher. If human
science, I said, has discovered the principle of the decay of things, it
is possible that human art may supply means of conservation, and bestow
immortality on some of the works which appear destined by their
perfection for future ages.

_The Unknown_.--I shall willingly communicate to you my views of the
operation of time, philosophically considered. A great philosopher has
said, man can in no other way command Nature but in obeying her laws;
and, in these laws, the principle of change is a principle of life;
without decay, there can be no reproduction; and everything belonging to
the earth, whether in its primitive state, or modified by human hands, is
submitted to certain and immutable laws of destruction, as permanent and
universal as those which produce the planetary motions. The property
which, as far as our experience extends, universally belongs to matter,
gravitation, is the first and most general cause of change in our
terrestrial system; and, whilst it preserves the great mass of the globe
in a uniform state, its influence is continually producing alterations
upon the surface. The water, raised in vapour by the solar heat, is
precipitated by the cool air in the atmosphere; it is carried down by
gravitation to the surface, and gains its mechanical force from this law.
Whatever is elevated above the superfices by the powers of vegetation or
animal life, or by the efforts of man, by gravitation constantly tends to
the common centre of attraction; and the great reason of the duration of
the pyramid above all other forms is, that it is most fitted to resist
the force of gravitation. The arch, the pillar, and all perpendicular
constructions, are liable to fall