n. Let the height of the capital be
divided into three parts, and give one to the plinth (that is, the
abacus), the second to the echinus, and the third to the necking with
its conge.

4. Upon the columns lay the main beams, fastened together, to a height
commensurate with the requirements of the size of the building. These
beams fastened together should be laid so as to be equivalent in
thickness to the necking at the top of a column, and should be fastened
together by means of dowels and dove-tailed tenons in such a way that
there shall be a space two fingers broad between them at the fastening.
For if they touch one another, and so do not leave airholes and admit
draughts of air to blow between them, they get heated and soon begin to
rot.

5. Above the beams and walls let the mutules project to a distance equal
to one quarter of the height of a column; along the front of them nail
casings; above, build the tympanum of the pediment either in masonry or
in wood. The pediment with its ridgepole, principal rafters, and
purlines are to be built in such a way that the eaves shall be
equivalent to one third of the completed roof.

CHAPTER VIII

CIRCULAR TEMPLES AND OTHER VARIETIES

1. There are also circular temples, some of which are constructed in
monopteral form, surrounded by columns but without a cella, while
others are termed peripteral. Those that are without a cella have a
raised platform and a flight of steps leading to it, one third of the
diameter of the temple. The columns upon the stylobates are constructed
of a height equivalent to the diameter taken between the outer edges of
the stylobate walls, and of a thickness equivalent to one tenth of their
height including the capitals and bases. The architrave has the height
of one half of the thickness of a column. The frieze and the other parts
placed above it are such as I have described in the third[5] book, on
the subject of symmetrical proportions.

[Illustration: _Photo. Anderson_

THE CIRCULAR TEMPLE AT TIVOLI]

[Illustration: THE MAISON CARREE AT NIMES, A PSEUDO-PERIPTERAL TEMPLE]

[Note 5: 1 Codd. _quarto._]

[Illustration: TEMPLE AT TIVOLI]

[Illustration: _From Durm_

PLAN OF THE TEMPLE OF VESTA AT ROME]

2. But if such a temple is to be constructed in peripteral form, let two
steps and then the stylobate be constructed below. Next, let the cella
wall be set up, recessed within the stylobate about one fifth of the
breadth thereof