use of Catulus, except that I have
substituted columns for walls. Beyond these columns at the end is
a grove of large transplanted trees forming a roof of leaves, but
admitting light underneath, as that is entirely cut off by the high
walls on the sides. Between the exterior row of columns of the
_tholus_, which are of stone, and the interior row, which are of pine,
there is a narrow space, five feet in width. The exterior columns are
filled in with a transparent net instead of walls, thus permitting the
birds to look out upon the grove and the wild birds there but without
escaping: the interior columns being filled in with the net of the
main aviary. The space between the two rows of columns thus enclosed
is equipped with perches for the birds in the form of many rods let
into all the columns in ascending array like the degrees of a theatre;
and here are enclosed all kinds of birds, but chiefly singing birds,
like nightingales and blackbirds, for whom water is conducted by means
of a small canal and food is supplied under the net. [_Under the
lantern of the tholus is a basin of water: and around this_] a foot
and nine inches below the stylobate or pedestal of the interior row
of columns, runs a stone platform. This is five feet in width and two
feet above the level of the basin, thus affording a space on which
my bird guests may hop about from the cushions to the little columns
[_which are there provided for them_].[171]

"The basin is immediately surrounded with a quay a foot in width
adjoining [but below the level of] the platform and has a little
island in the middle. Around the platform and the quay are contrived
docks for ducks. On the island is a little column arranged to turn
on its axis and carrying a wheel-shaped table with hollow drum-like
dishes fashioned at the ends of the spokes two and a half feet wide
and a palm in depth. This is turned by a boy whose business that is,
so that meat and drink is put before all my bird guests in turn. From
the elevation of the platform, where mats are usually placed, the
ducks go out to swim in the basin, and from this streams flow into
the two basins I have already described, and little fish may be seen
darting from one to the other, while warm or cold water may be turned
on the guests from the circumference of the revolving table, which I
have described as equipped with spokes.

"Within the dome is an arrangement to tell the hours by marking the
position in the heavens