Solomon had done was to teach him to have a glad heart. All birds
have glad hearts unless you rob their nests, and so as they were the
only kind of heart Solomon knew about, it was easy to him to teach
Peter how to have one.

Peter's heart was so glad that he felt he must sing all day long, just
as the birds sing for joy, but, being partly human, he needed in
instrument, so he made a pipe of reeds, and he used to sit by the
shore of the island of an evening, practising the sough of the wind
and the ripple of the water, and catching handfuls of the shine of the
moon, and he put them all in his pipe and played them so beautifully
that even the birds were deceived, and they would say to each other,
"Was that a fish leaping in the water or was it Peter playing leaping
fish on his pipe?" and sometimes he played the birth of birds, and
then the mothers would turn round in their nests to see whether they
had laid an egg. If you are a child of the Gardens you must know the
chestnut-tree near the bridge, which comes out in flower first of all
the chestnuts, but perhaps you have not heard why this tree leads the
way. It is because Peter wearies for summer and plays that it has
come, and the chestnut being so near, hears him and is cheated.

But as Peter sat by the shore tootling divinely on his pipe he
sometimes fell into sad thoughts and then the music became sad also,
and the reason of all this sadness was that he could not reach the
Gardens, though he could see them through the arch of the bridge. He
knew he could never be a real human again, and scarcely wanted to be
one, but oh, how he longed to play as other children play, and of
course there is no such lovely place to play in as the Gardens. The
birds brought him news of how boys and girls play, and wistful tears
started in Peter's eyes.