Just occasionally in Blake’s engravings there are pictures within pictures, and we get a glimpse of the life he thought images might lead in a better world. The most moving of these visions is Plate 20 of Blake’s Illustrations of the Book of Job. Job has survived his doubts and torments, and is telling the story to his daughters – in an earlier watercolour, they hold the instruments of Poetry, Painting and Music. No doubt the young women are taking their father’s narrative to heart, and in due course will rephrase it in terms appropriate to their arts: the lute and lyre are in the margins of the plate, ready to be strummed. But the first form of the story is visual: Job sits in a circular room – or maybe it is ten or 12-sided – and points towards two frescoed roundels on the walls left and right. Neither is unequivocally an episode from Job’s life – they could be analogous scenes from the story of the Fall – but the square panel over his head must be a version of ‘Then the Lord answered Job out of the Whirlwind.’ (It combines and condenses elements of Blake’s previous engraving of the subject.) As so often in Blake, the balance between positive and negative in the scene as a whole is precarious: Job is central and patriarchal (‘their Father gave them Inheritance among their Brethren’), and there is more than a touch of the baleful exhausted God-the-Father to him, heavy lids, pointing fingers and all. But there cannot be any doubt that the basic form and function of the room, with its echoes of the early 19th-century diorama (it is important that the plate was engraved in 1825), were meant to strike the viewer as wonderful – all-enveloping. Here were images at work.