Final answer:
The quote 'That melancholy convention cannot be persuasive' means that a sad event or circumstance is not able to convince or influence someone.
Step-by-step explanation:
The quote 'That melancholy convention cannot be persuasive' is from the Myth of Sisyphus and it means that this gloomy and sad event or circumstance is not able to convince or influence someone.
The word 'melancholy' refers to a deep sadness or sorrow, while 'convention' could refer to a social or cultural behavior or practice. In the context of the quote, it suggests that this particular event or circumstance lacks the power to persuade or change someone's perspective.