rest of the vaulting, comprising the four spandrels
together with the border that we have already mentioned as enclosing
the oval all around, shall be made to appear as the unbroken surface
within the chamber, and as resting upon the facades, with some
beautiful architectural design of your own devising. The four lunettes
I would have counterfeited as likewise concave; and, whereas the oval
above represents a heaven, these must represent heaven, earth, and
sea, as if without the chamber, in accordance with the various
figures and scenes that shall be there. And since, the vaulting being
very flat, the lunettes are so low that they will not hold any but
little figures, I would divide each lunette into three parts along its
length, and, leaving the ends in a line with the height of the
spandrels, I would deepen the centre part below that line, in such a
manner that it may be like a great high window and show the exterior
of the room, as it were, with figures and scenes proportionate in size
to the others. And the two extremities that remain on either side,
like horns to the lunette--and horns henceforward they will be
called--shall be left low, of the height that they are above that
line, and in each of them must be painted a figure seated or
recumbent, and seeming to be either within or without the room,
whichever you please, for you must choose what looks best; and what I
say of one lunette I say of all four.

"To return to the interior of the chamber as a whole, it appears to me
that it should be in itself all in darkness, save in so far as the
concavities both of the oval above and of the large windows at the
sides may give it a certain degree of light, partly from the heaven,
with its celestial lights, and partly from the earth with fires that
must be painted there, as will be described later. At the same time,
from the centre of the room to the lower end, I would have it that the
nearer one may approach to the foot, where the Night is to be, the
greater shall be the darkness, and that in like manner in the other
half, from the centre to the upper end, in proportion as one
approaches step by step to the head, where Aurora is to be, it shall
grow continually lighter.

"Having thus disposed of the chamber as a whole, let us proceed to
distribute the subjects, giving to each part its own. In the oval that
is in the vaulting, you must paint at the head, as we have said, a
figure of Aurora. This figure, I find, may be