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