A pendulum of horror

In 1842, the first American author of tales of horror, Edgar Allen Poe (1809-1849) wrote a short story entitled, The Pit and the Pendulum. Poe’s stories often contained a strong element of terror, in part, because he left many of the details quite vague, just as a standard technique of psychological terror is to keep the victim in ignorance as to his ultimate fate.
The Pit and the Pendulum does exactly that to both the reader and the protagonist. The main, and practically only character, whose name we never know, is brought as a prisoner before the court of the Spanish inquisition in Toledo, Spain. The trial is recalled by the prisoner during a confused dreamlike state. Subsequently, he is carried into the bowels of the earth and flung into a damp and dark dungeon.
He attempts to investigate the physical condition of his cell but exhaustion forces sleep upon him.
When our hero awakes, he is tied to a low cot with only one hand free with which to feed himself the spiced meat that is mysteriously laid beside the cot. He now notices a large pendulum high above the cot and observes the start of its oscillations.
However, the presence of rats attempting to steal his food distracts his attention from the pendulum. Meanwhile the pendulum bob, now seen to be in the shape of a large sharp metal blade, comes ever closer to his person.
The descent of the pendulum is tortuously slow giving our hero a chance to assess his situation. The strap by which he is held to the cot is a long single piece that is wound many times around his body.
His first thought is that the pendulum might eventually cut the strap and allow him to free himself before he suffers his apparently inevitable fate.
But, to his chagrin, he notes that the only place where the strap does not cover his body lies in the path of the pendulum.
Therefore he needs to devise some other method of regaining freedom of movement.
The story continues as the pendulum draws ever closer with increasingly larger amplitudes for swing.

O Botafumerio, the giant censer that hangs in the transept of the cathedral of Santigo de Compostela. The rapid motion through the air fans the hot incense coals, making copious amounts of blue smoke, and the censer itself generates a frightening swooshing sound as it passes through the bottom of its arc

Like O Botafumerio, this pendulum can also be heard to make an ominous swishing sound as it describes its increasing arc. As the pendulum nears the prisoner’s body he estimates the total range of the pendulum’s motion to be about thirty feet.
Given that the room itself is only about forty feet high, this pendular motion is of very large amplitude, again similar to O Botafumerio. At this point we refer readers to the original story in order to learn the fate of the prisoner.
However, it is of interest to ask whether Poe’s tale is realistic. Does it seem likely that the inquisition would have used something like a motorized pendulum in this context?
The answer is probably no. The time frame of the story is not clear but we may impose some limitations. The Spanish inquisition ended in the early nineteenth century and the story itself refers to capture of the city by a contain French General La Salle.
Perhaps this allusion is to the Napoleonic wars, but the time could also be much earlier. Scholars (LLorente 1823; Lea 1907) suggest that while torture was a standard and accepted means of learning truth in matters both secular and religious, it was not likely to be used gratuitously by the inquisition once sentence had been passed. And, in the story, there had been a trial and a sentence pronounced.
Furthermore, instruments of torture were fairly simple and direct. A driven pendulum that would slowly and noiselessly descend, and slowly increase its amplitude of motion, all inside and above a small dungeon, is relatively complex and hardly worth the effort even if craftsmen could be found to build such a machine.
Therefore Poe’s story is somewhat unrealistic in this regard. Some believe that the inspiration for Poe’s tale was actually a large swinging bell that Poe had observed. Nevertheless, realistic or not, the image of a sharp-edged pendulum makes it frightening.
It is the regularity and inexorability of the pendulum’s motion that contributes to the climate of terror found in this story. The pendulum’s periodicity, that is so important in other contexts, is here made to serve the cause of literary suspense…..
The pendulum: a case study in physics, Gregory L. Baker,James A. Blackburn