plinth or abacus, another to the echinus, the third to the
hypotrachelium, with its apophyge. Over the columns
coupled beams are laid of such height as the magnitude
of the work may require. Their width must be equal to
that of the hypotrachelium at the top of the column, and
they are to be so coupled together with dovetailed dowels
as to leave a space of two inches between them. For if
they are laid touching each other, and the air does not play
round them, they heat and soon rot. Above the beams and
walls the mutuli project one fourth the height of the co-
lumn. In front of these members are fixed, and over them
the tympanum of the pediment, either of masonry or tim¬
ber. Above the pediment the ridge-piece (columen).
rafters (cantherii), and purlines (templa), are distributed
so that the water may drip therefrom on three sides. Cir¬
cular temples are also constructed, of which some are
MONOPTERAL, having columns without a cell ; others are
called PERIPTERAL. Those without a cell have a raised
floor (tribunal), and an ascent thereto equal to one third
of their diameter. On the pedestals (stylobatæe) columns
are raised, whose height is equal to the diameter which
the pedestal occupies, and their thickness, including the
bases and capitals, one tenth part of their height. The
height of the architrave is half a diameter; the frieze and
members over it are to be proportioned according to the
directions to that effect which have been given in the third
book. But if the building be peripteral, two steps, and
then the pedestals are built thereunder ; the wall of the
cell is raised at a distance from the pedestals of about
one fifth of the whole diameter, and in the middle is
left an opening for the door. The clear diameter of
the cell within the walls, is to be equal to the height of