In line at a crossing
we wait for the barrier to rise:
its upswing paused, outside control.
Arrested, teetering,
our gated state is two-wheeled doubt.
‘Talk
to us’ the notice says
if
things are getting to you.’
When pulsing red turns single green
we will pass this border;
beyond, where streetlamps run out,
shall plunge into the moonless ink.
Unnerved, our widening eyes
cannot discriminate
the ivied limbs, closing over.
What’s known becomes unknown.
Flickering between margins
of bracken bank and leaf-choked
swamp,
feeble bike lights fail to see
the path that’s safe not sorry.
A bridge is looming. Until then
wobbly guesswork guides our wheels.
xii. 2017
The Purkinje effect (or 'dark adaptation') is the shift in sensitivity of the human eye toward the shorter wavelength, blue end of the spectrum in dim light.
ReplyDeleteBoth it and the reflected image of the retina's vascular tree are named after the Czech anatomist and physiologist, Jan Purkyně (1787-1869).