Rhyme refers to the repetition of similar sounds at the ends of lines in poetry. In the given poem, there is a clear use of rhyme scheme, particularly in the second and fourth lines of each stanza. For example:

- "Sleep, O sleep" and "I cease to weep" rhyme.
- "By thy power" and "Enjoys the happy hour" rhyme.
- "What's to sleep?" and "So may I always keep" rhyme.

This consistent pattern of rhyming pairs throughout the poem indicates the use of rhyme as a poetic device.

End-stopped lines are also used in the poem

"Sleep, O sleep" ends with a comma, creating an end-stopped line.
"Charm my Imagination," also ends with a comma, indicating another end-stopped line.

These pauses or stops help to emphasize the completion of a thought or idea within the line itself. 

However, it is important to note that rhyme is more dominant than end-stopped lines. The poem's structure relies heavily on rhyme, as evidenced by the consistent rhyme scheme throughout the stanzas. Each stanza follows a rhyme scheme.

On the other hand, while there are some end-stopped lines in the poem (lines that end with punctuation, creating pauses or stops), they are not as prominent or defining as rhyme.