Wordsworth employs—and then deliberately deconstructs—the Petrarchan sonnet form. 

The Petrarchan sonnet is a disciplined poetic form that dates to Renaissance Italy. It consists of 14 lines of tightly rhymed (ABBAABBA CDCDCD) iambic pentameter (10 syllables per line, following a stress/non-stress pattern). Traditional Petrarchan sonnets examine a moment of intense emotional crisis such as unrequited or separated love. The first eight lines (the octave) express the problem; the closing six lines (the sestet) pivot to offer an elegant and hopeful resolution. 

“Surprised by Joy” fractures the classic form. The problem/solution break comes late, in the middle of Line 9. The meter varies (Line 6, for instance, has 14 syllables). The rhyme scheme is eccentric, often relying on sight rhymes (“wind,” “find,” and “mind”; “return” and “forlorn”). 

In upending the form and meter of a Petrarchan sonnet, Wordworth suggests that his speaker’s emotional crisis is beyond tidy repair. Indeed, here the closing couplet only underscores the depth of the poet’s sorrow. The speaker has only his grief. This sonnet is barely contained chaos, which in turn suggests the emotional turmoil churning in his wounded heart.