Which Nature hung in heaven, and filled their lamps
With everlasting oil to give due light
To the misled and lonely traveller?
When Milton does fall into a vein of conceit, it is generally both trivial and obvious, with none of the saving quality of Donne's remoter extravagances. In Donne they are hardly extravagances; the vast overshadowing canopy of his imagination seems to bring the most wildly dissimilar things together with ease. To his unfettered and questioning thought the real seems unreal, the unreal real; he moves in a world of shadows, cast by the lurid light of his own emotions; they take grotesque shapes and beckon to him, or terrify him. All realities are immaterial and insubstantial; they shift their expressions, and lurk in many forms, leaping forth from the most unlikely disguises, and vanishing as suddenly as they came.
Sometime we see a cloud that's dragonish;
A vapour sometime like a bear or lion,
A tower'd citadel, a pendent rock,
A forked mountain, or blue promontory
With trees upon't that nod unto the world,
And mock our eyes with air: thou hast seen these signs;