A Cloud in a Box

Hidden away
Behind doors and locks
A magician kept
A cloud in a box
Once a week
He'd display his prize
To the great surprise
Of questioning eyes
A young girl said
It was sad to see
And wasn't it time
To set it free?
A schoolboy declared
That it shouldn't exist
How did it get there
This fluffy white mist?

The magician shrugged
And would only reply:
That was a secret
Between him and the sky