Perhaps it will be found that to work all by day or all by night is to miss something of the powers of a complex mind.  One might imagine the rhythmic experience of a poet, subject, like a child, to the time, and tempering the extremities of either state by messages of remembrance and expectancy.

Never to have had a brilliant dream, and never to have had any delirium, would be to live too much in the day; and hardly less would be the loss of him who had not exercised his waking thought under the influence of the hours claimed by dreams.  And as to choosing between day and night, or guessing whether the state of day or dark is the truer and the more natural, he would be rash who should make too sure.

In order to live the life of night, a watcher must not wake too much.  That is, he should not alter so greatly the character of night as to lose the solitude, the visible darkness, or the quietude.  The hours of sleep are too much altered when they are filled by lights and crowds; and Nature is cheated so, and evaded, and her rhythm broken, as when the larks caged in populous streets make ineffectual springs and sing daybreak songs when the London gas is lighted.  Nature is easily deceived; and the muse, like the lark, may be set all astray as to the hour.  You may spend the peculiar hours of sleep amid so much noise and 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.