'The fair breeze blew, the white foam flew,
The furrow followed free' is an example of -

Repetition of consonant sounds at the beginning of words or stressed syllables is known as alliteration.
Example: “Puffs, powders, patches, Bibles, billet-doux''. (Pope: The Rape of the Lock)
Here, ''p'' and ''b'' have been repeated.
Another example: The fair breeze blew, the white foam flew,
The furrow followed free;
(Coleridge: The Rime of the Ancient Mariner)
Here, ''f'' and ''b'' have been repeated.
Source: An ABC of English Literature - Dr M Mofizar Rahman