e plans
of buildings as the ellipse, the circle, and the octagon, and their
facile use, seem to denote a people who could build rapidly, and who
looked carefully to the general masses and outlines of what they
built, however carelessly they handled the minute details. The freedom
with which these new forms were employed arises partly also from the
fact that the Romans were in possession of a system of construction
which rendered them practically independent of most of the
restrictions which had fettered the genius of the Egyptians,
Assyrians, and Greeks. Their vaulted roofs could be supported by a
comparatively small number of piers of great solidity, placed far
apart; and accordingly in the great halls of the Thermae and elsewhere
we find planning in which, a few stable points of support being
secured, the outline of the spaces between them is varied at the
pleasure of the architect in the most picturesque and pleasing manner.

The actual floor received a good deal of attention from the Romans. It
was generally covered with tesselated pavement, often with mosaic, and
its treatment entered into the scheme of the design for most
interiors.

_The Walls._

The construction of these was essentially different from that adopted
by most earlier nations. The Romans rather avoided than cultivated the
use of large blocks of stone; they invented methods by which very
small materials could be aggregated together into massive and solid
walls. They used mortar of great cementing power, so much so that many
specimens of Roman walling exist in this country as well as in Italy
or France, where the mortar is as hard as the stones which it unites.
They also employed a system of binding together the small materials so
employed by introducing, at short distances apart, courses of flat
stones or bricks, called "bond courses," and they further fortified
such walls by bands of flat materials placed edgeways after the manner
popularly known as herring-bone work. The result of these methods of
construction was that the Roman architect could build anywhere, no
matter how unpromising the materials which the locality afforded; that
he could put the walls of his building together without its being
requisite to employ exclusively the skilled labour of the mason, and
that both time and expense were thus saved. This economy and speed
were not pushed so far as to render the work anything but durable;
they had, however, a bad effect in another dire