The Air

What is this dark and silent caravan
that being nowhere, neither comes nor goes;
that being never, has no hour or span;
of which we can say only that it flows?
How was it that this empty datastream,
this cache of dead light could so lose its way
it wandered back to feed on its own dream?
How did that dream grow to the waking day?
What is the sound that fades up from the hiss,
like a glass some random downdraught had set ringing,
now full of its only note, its lonely call,
drawing on its song to keep it singing?
When will the air stop breathing? Will it all
come to nothing, if nothing came to this?