In Edgar Allan Poe’s short story The Cask of Amontillado, nitre refers to a mineral deposit, specifically potassium nitrate, which forms on the walls of the catacombs. Nitre is often found in damp, underground environments and is commonly known as saltpeter.
In the story, the presence of nitre adds to the eerie and oppressive atmosphere of the catacombs. As Montresor and Fortunato descend deeper into the vaults, the nitre-covered walls symbolize the decay and death that surround them. Montresor even mentions the nitre, warning Fortunato about its effects, which further heightens the sense of foreboding.
The nitre also serves a practical purpose in the story. It helps to create a realistic setting, as catacombs and underground vaults are often damp and prone to such mineral deposits. This attention to detail enhances the story’s credibility and immerses the reader in the dark, claustrophobic world of the catacombs.