to sleep, or not to sleep

 I returned Yeats to the library; now I have Wordsworth. 

This evening I hankered for a hot cocoa, so I had one, but I wonder if the caffeine will disturb my sleep.

TO SLEEP

A flock of sheep that leisurely pass by,
One after one; the sound of rain, and bees
Murmuring; the fall of rivers, winds and seas,
Smooth fields, white sheets of water, and pure sky;
I have thought of all by turns, and yet do lie
Sleepless! and soon the small birds' melodies
Must hear, first uttered from my orchard trees;
And the first cuckoo's melancholy cry.
Even thus last night, and two nights more, I lay
And could not win thee, Sleep! by any stealth:
So do not let me wear tonight away:
Without thee what is all the morning's wealth?
Come, blessed barrier between day and day,
Dear mother of fresh thoughts and joyous health!

- William Wordsworth