The last flowers to go out
There is a stretch at the end of a clear evening — twenty minutes, half an hour — when there is still plenty of light and no sun. Enough to find a keyhole by. Not enough to read a page. Anyone walking home through it goes past gardens, and the gardens are not the colour they were at lunchtime. The white hydrangea against the fence has come up: it is nearly luminous, holding more light than seems reasonable for a flower standing in the dark. The red geraniums in the pot beneath it — which at noon were the loudest thing on the street, which are the entire reason anybody planted geraniums — have gone. Not dimmed. Gone. A dark clot in a dark pot, nearer soot than red.
You have walked through this ten thousand times, and if somebody stopped you at the gate and asked, you would say the light was going. Which is true, and explains nothing, because the light is going for the hydrangea too. Turning everything down together cannot put one flower in front of another. At midday the ranking on that fence ran red, white, blue. By half past nine it runs blue, white, and then a gap, and red is not so much last as unlisted. Somebody has re-ordered the garden while you were at work.
Not the garden. Two systems handle the light coming in: one that reports colour and needs a decent supply to work with, and one that reports no colour at all and can run on almost nothing. Through the middle of the day the first does the talking. As the light drops, the second takes the shift. And the second is not a poorer copy of the first — it has different taste. It is tuned nearer the blue end. So as the evening comes down, the blues and whites are handed to an instrument that likes them, and the reds are handed to one that barely registers them at all. The flowers are unchanged. The tabulation is new.
A man called Purkyně worked this out in the 1820s by walking, repeatedly, at dawn. He noticed that his favourite flowers did not hold their order — that the ones blazing before sunrise were unremarkable by breakfast — and instead of correcting the observation, which is what you do with an inconvenient eye, he trusted it and wrote it down. The shift carries his name now. The whole discovery was declining to call the difference an error.
What stays odd about it is the handover itself, which nobody has ever seen. The rest of the evening you can watch happen: shadows lengthen, a lamp comes on in a kitchen, the sky loses its floor. This one you cannot catch, however carefully you stand there, because the thing being switched over is the thing doing the watching. You do not notice the changeover. You arrive on the far side of it and find the arrangement already different, with no memory of it being different, and no memory of the moment it changed.
Which leaves the small nightly fact that people file under getting dark: it isn't a fade. The garden goes out in order — reds, then yellows, then everything but the white things, which stand there at the end holding what light is left, apparently lit from inside. The order never varies. And the order does not belong to the garden.