How does Poe use setting to enhance the atmosphere of horror in "The Cask of Amontillado"?

The horror in the story of "The Cask of Amontillado" is that a man announces his intentions to take cold-blooded revenge--thorough cold-blooded revenge--against another man who believes in their sincere friendship and who has no knowledge of having offended. The horror is doubled because the man seeking revenge has planned and plotted with longsuffering patience to conceive of and execute a revenge that leaves him free of impunity before the law while making his punishing revenge fully felt by the other. This is the fundamental horror of the story. Three of the settings, for there are four settings, add to the atmosphere of horror built into the story: (1) the unidentified opening setting where he is telling the secret of his fifty-year-old tale to, presumably, a family relation--perhaps his heir--who seemingly has some vested interest in knowing; (2) the second setting of the festival; (3) the third setting of the catacombs; (4) the fourth setting of the niche destination at the "most remote end of the [deep] crypt...."

The carnival setting, "about dusk ... during the supreme madness of the carnival season," furnishes a festive counterpoint to the catacombs of death that Montresor invites Fortunato to visit, while the carnival's "supreme madness" parallels the revenge Montresor ventures upon. It is through counterpoint and parallel that the second of four settings enhances the atmosphere of horror, which builds in intensity through their journey together into the catacombs. While in the carnival setting, with costumes of festivity adorning their persons ("The man wore motley ... surmounted by the conical cap and bells") and with noise and laughter and gaiety all about, Montresor's conversation about the "pipe of Amontillado," somewhat out of place for a carnival night, starts the descent into ironic, satirical cruelty disguised as carnival liveliness: anything may be allowed on such a night, even descent into death.

The festivities of the carnival setting further add to the atmosphere of horror as we see that Montresor plans to slyly torment Fortunato on their entire journey to the impressive Amontillado as when he mentions Fortunato's rival, Luchresi, or as later in the catacombs when he gives a farcical "secret" sign of the Masonic Lodge in the form of his trowel: "'You jest,' [Fortunato] exclaimed, recoiling a few paces." It is Fortunato's greed to taste the Amontillado that compels him headlong into Montresor's trap, causing him to leave the company of the festive carnival to enter death's catacomb's, even though he seems to have a social engagement although he denies it: "'I perceive you have an engagement.' ... 'I have no engagement,....'"

Fortunato's greed isn't caused by a tendency to dissipation but by the rarity of an Amontillado, which, according to SherryNotes.com, is a type of Sherry aged twice for eight years or more, once under flor yeast, with the flor failing to develop, then with oxidization. At the time in which the story is set, the flor failed because of organic problems with the development of the aging process although now interruption of flor development is intentionally introduced. The origins of Amontillado make it rare and, as Fortunato suggests, difficult to distinguish from ordinary Sherry, which explains why Fortunato says of his rival, "'Luchresi cannot tell Amontillado from Sherry.'"

Montresor lures Fortunato to the next setting by tempting him with this "Amontillado." The catacomb setting (catacomb: underground tomb for the placement of dead people, often on exposed shelves) adds to the atmosphere of horror because in the catacombs Poe adds layer upon layer of troubling details that threaten Fortunato in such a way that Montresor continually says with feigned concern (without any sincerity at all) that they should turn back either because Montresor might just as easily consult the incompetent rival Luchresi or because of Fortunato's cough: "The drops of [nitre] moisture trickle among the bones. Come, we will go back ere it is too late." The mounting detail of the catacombs combined with the mounting feeling of dread and suspense the setting engenders enhance the heightening atmosphere of horror.

When they get to the fourth and final setting, to the destination selected by Montresor, to the place where he will use his trowel--which he earlier brandished in a compulsive mock jest before Fortunato--to wall in his drunken, gullible enemy, the horror is magnified by the surprises and twists abruptly introduced here. The menaces of this setting enhance the atmosphere of horror because we are as confused by it as Fortunato himself is as he walks into a niche--which symbolically marks the end of his good fortune--where he "stood stupidly bewildered." Neither we nor he can fathom the meaning of the niche, nor of the "rock" that blocks his path, nor of the "fetters" that astound us as they astound him, nor of the purpose of Montresor digging purposefully about in "a pile of bones." The surprises and twists of this fourth setting serve to enormously enhance the atmosphere of horror as bewilderment, confusion and astonishment--"He was too much astounded to resist ... [and] not yet recovered from his astonishment"--immobilize Fortunato while bewildering and shocking us.

To summarize, this analysis reveals that Poe prominently uses three techniques related to setting to enhance the atmosphere of horror in the story: (1) the contrapuntal natures of the two early settings, i.e., the carnival of joy as a contrasting counterpoint to the catacombs of death; (2) the mounting details revealing the mounting dangers of the catacomb crypts, including farcical or ironic details, e.g., the farcical jolly bells of Fortunato's costume, the ironic nitre dripping, which is potassium nitrate and potentially dangerous to lungs; (3) the surprises that twist the pattern of what has already occurred, e.g., that the succession of deep crypts should end in a darkened "niche" where "his progress [was] arrested by the rock."