ese columns
three quarters are to be seen, and the other quarter is merged into
the corner, with the accompaniment of the half of a pilaster that
makes a salient angle on the inner side, and this is accompanied in
the central inner space by the opening of an arched door, five palms
wide and thirteen palms and five inches high, from the summit of which
to the capitals of the pilasters and columns there is a filling of
solid masonry, serving as a connection with two other pilasters that
are similar to those that form a salient angle beside the columns.
These two pilasters correspond to the others, and adorn the sides of
sixteen windows that go right round the tribune, each with a light
twelve palms and a half wide and about twenty-two palms high. These
windows are to be adorned on the outer side with varied architraves
two palms and three-quarters high, and on the inner side they are to
be adorned with orders likewise varied, with pediments and
quarter-rounds; and they are wide without and more narrow within, and
so, also, they are sloped away at the foot of the inner side, so that
they may give light over the frieze and cornice. Each of them is
bordered by two flat pilasters that correspond in height to the
columns without, so that there come to be thirty-six columns without
and thirty-six pilasters within; over which pilasters is the
architrave, which is four palms and three-quarters in height, the
frieze four and a half, and the cornice four and two-thirds, with a
projection of five palms; and above this is to go a range of
balusters, so that one may be able to walk all the way round there
with safety. And in order that it may be possible to climb
conveniently from the level where the columns begin, another staircase
ascends in the same line within the thickness of the part that is
fifteen palms wide, in the same manner and of the same width, with two
branches or ascents, all the way up to the summit of the columns, with
their capitals, architraves, friezes, and cornices; insomuch that,
without obstructing the light of the windows, these stairs pass at the
top into a spiral staircase of the same breadth, which finally reaches
the level where the turning of the tribune is to begin.

All this order, distribution, and ornamentation is so well varied,
commodious, rich, durable, and strong, and serves so well to support
the two vaults of the cupola that is to be turned upon it, that it is
a very ingenious thing, and it is