Question

I must go down to the seas again, to the lonely sea and the sky,

Answer 1

Sky rhymes with by and shaking rhymes with breaking.

Answer 2

In this stanza, there are two different sounds that produce rhyme. The word by creates an end rhyme with the word sky because of the final sound /ai/. Also, the word breaking creates an end rhyme with the word shaking because of the final "ing" sound. Even though the words are not in consecutive lines, the rhyme still exists.