Take a story's temperature by studying its tone. Is it hopeful? Cynical? Snarky? Playful?
Could it really be any other way? Dumas tackles a lot of weighty material, and he recognizes it as such. Many of the Count's machinations – forcing Albert and Franz to watch the execution, buying the "dapple-grays," bringing Bertuccio back to the scene of his crime, manipulating the telegraph – are darkly humorous or just plain clever; but, because we know that each event is part of a complex and solemn plan, we have to take things seriously.