Fig. 3.]

Now get the mason to come with his cement and some bricks, and build up
on the selected site a level foundation for the house to rest on,
spreading a layer of cement along the top of the upper course of bricks,
to which the base of the frame-work (which must be lifted on to it while
it is moist) will adhere. Then, to give additional stability, and lessen
the risk of the house being lifted or shifted by a gale (for, being open
in front and sides, it will offer, like the inside of an open umbrella,
far greater resistance to the wind than would be the case if glazed as a
greenhouse is), an inner line of bricks is next cemented against the
side of the bottom rafters all round, and flush with their surface, as
seen at Fig. 3. Lastly, when the floor has been paved with bricks, the
mason's job is finished.

[Illustration: Fig. 4.]

[Illustration: Fig. 5.]

Now comes the roof. This is made to play out widely for two purposes: to
give our aviary a somewhat ornamental appearance, and also to carry the
drip well clear of the walls and wire netting. First of all, the boards,
B (Fig. 4), must be nailed on, planed surface downward, to form a smooth
ceiling; then the whole is covered with strips of stout canvas, A,
overlapping one another. The ends of the canvas are fastened tightly
under the eaves, and the exposed selvedge of one strip, with the
selvedge of the next beneath, is properly tacked to the wood. Finally
the top piece, C, and the narrow strips of wood, B (Fig. 5), being
securely nailed on over the canvas, the roof is complete; and when
painted with _light_ lead-color, it will be perfectly water-proof, and
have the appearance, without the weight, of a real leaden covering.

[Illustration: Fig. 6.]

[Illustration: Fig. 7.]

There remain the sides to be walled up. The boards for these can now be
nailed on from the bottom upward, with the exception of the pieces H H
(Fig. 6), which must be left over until the wire netting has been
attached to the upright pillars. A window two feet square, of a single
pane of strong glass, well bedded in putty, to give more light to the
interior, without extra draught, and with wire netting over the glass on
the inside, is placed at the back, where also is seen the door,
capacious enough for a person to get in and clean out the aviary when
required; for which purpose three feet by two feet will give sufficient
room. But we do not want the bother of unfastening this big door, an