What are light squibs? They are not a handful of hawthorn flowers in an empty hedge – but, looking at such a hedge on a dark December afternoon, it seems as though they might be. The hedge is an expanded and frozen universe; the flowers some last squibs of light.

John Donne brought light squibs into his poem ‘A nocturnall upon S. Lucies day, Being the shortest day’. ‘The Sunne is spent,’ wrote Donne, ‘and now his flasks | Send forth light squibs, no constant rayes’. Now this poem was written at the beginning of the seventeenth century, so this is unlikely to be a reference to particle physics or the cooling of the universe. Even so, there are particles here: light has lost its unity and the (uni)verse shivers into single syllable words:

Tis the yeares midnight, and it is the dayes,
Lucies, who scarce seaven houres herself unmaskes,
The Sunne is spent, and now his flasks
Send forth light squibs, no constant rayes;

This is the opening of Donne’s poem. As it moves on, it offers up the poet as a kind of scientific experiment: he is extracted from ‘nothingnesse’ and ‘re-begot | Of absence, darknesse, death; things which are not’. Donne, in his alchemical way, creates seventeenth-century dark matter. But what I find myself lingering over are those opening words: ‘no constant rayes’. It is a simple negation – the emptying of that vast hedge of flowers – but in it is a loss of an entire world. It is not so much a loss of light as a loss of a way of understanding it. A light squib might well be a kind of firework (you can hear it fizzling in Donne’s words) but it is also a fragment. Just the sound of the word means that it is over before it gets started. There are no more constant rays – just particles. A few flowers left on a hedge. An expanded universe. Light squibs. There they are: the most perfect scrunched-up vanishing points.