What are we going to do with experience? In some poems, the very experience of making the poem itself is conveyed, as though the technical impulse, the urge to find the right words, sound patterns and rhythmical system might be enough to satisfy some need within the poet’s nervous system. It matters then what the poem mysteriously does as the poem becomes close to a musical performance. It matters less what the poem says, or what it is about.

There is a beautiful moment in the ancient Irish narrative Toraiocht Dhiarmada agus Grainne in which the king, now an old man, has wished to marry the young and beautiful Grainne, who in turn has convinced Diarmaid, one of the king’s handsome warriors, to run away with her. As they are pursued across Ireland, Diarmaid, out of loyalty to the king, is unwilling to make love with Grainne. She taunts him as they cross a stream, telling him that the water that has splashed her thigh is braver than he is. And thus they become lovers.

Eavan Boland’s version of the story, called ‘Song’, appears in her 1975 collection The War Horse. The first of four six-line stanzas has twenty-seven words, a comma, a semi-colon and a full-stop. Twenty-four of the words have only one syllable. The other three need more time; they take time; they are almost the key words – ‘outsleep’; ‘water’; ‘afraid’. The beat is iambic trimeter, with a variation in the fourth line ‘Too fast, too fast’ which matches the meaning, catches the speed, not ...