among so many people that you shall not be aware of them; you may thus
merely force and prolong the day. But to do so is not to live well both
lives; it is not to yield to the daily and nightly rise and fall and to
be cradled in the swing of change.

There surely never was a poet but was now and then rocked in such a
cradle of alternate hours. "It cannot be," says Herbert, "that I am he
on whom Thy tempests fell all night."

It is in the hours of sleep that the mind, by some divine paradox, has
the extremest sense of light. Almost the most shining lines in English
poetry--lines that cast sunrise shadows--are those of Blake, written
confessedly from the side of night, the side of sorrow and dreams, and
those dreams the dreams of little chimney-sweepers; all is as dark as he
can make it with the "bags of soot"; but the boy's dream of the green
plain and the river is too bright for day. So, indeed, is another
brightness of Blake's, which is also, in his poem, a child's dream, and
was certainly conceived by him in the hours of sleep, in which he woke to
write the Songs of Innocence:-

O what land is the land of dreams?
What are its mountains, and what are its streams?
O father, I saw my mother there,
Among the lilies by waters fair.
Among the lambs clothed in white,
She walk'd with her Thomas in sweet delight.

To none but the hours claimed and inspired by sleep, held awake by
sufferance of sleep, belongs such a vision.