Final answer:
A comma at the end of a line in poetry typically signals the reader to pause, adding rhythm and giving the idea presented more resonance before continuing.
Step-by-step explanation:
A comma at the end of a line of poetry typically indicates that the reader should pause at the end of the line. This punctuation mark helps to control the flow of the poem and allows for the idea to resonate before proceeding to the next line.
In the context of eighteenth-century heroic couplets, the use of end-stopped lines with commas, semi-colons, or full stops at their endings, was characteristic to impart a sense of balance, harmony, and proportion to the poem.
Unlike with enjambment, where a line runs onto the next without a punctuated pause, end-stopped lines create a formal rhythm, influencing the reader's interpretation through controlled pauses.