I never saw a more interesting creature: his eyes have generally an expression of wildness, and even madness, but there are moments when, if anyone performs an act of kindness towards him or does him any the most trifling service, his whole countenance is lighted up, as it were, with a beam of benevolence and sweetness that I never saw equalled.
Letters, Letter 4 · Robert Walton
Context
Walton describes Victor's demeanor after several days of recovery, noting the striking contrast between his usual wildness and the transformation that occurs when someone shows him kindness.
Analysis
The syntax mirrors the transformation it describes: the sentence begins with "wildness, and even madness," then pivots at "but there are moments" into an extended image of light. By making readers experience the long wait for that shift—piling up clauses before reaching "benevolence and sweetness"—Shelley recreates the experience of witnessing Victor's face change, so the grammatical structure enacts the emotional one.
Essay Tip
Use this to argue that Shelley builds sympathy for Victor not through his words but through Walton's structural pacing—the delayed arrival of the positive image makes those moments of kindness feel rare and precious, positioning Victor as a tragic figure despite his flaws.