We know what the titular pit and pendulum are meant to do: frighten, torture, and kill. As the narrator notes, however, his jailors could have simply burned him at the stake if they just wanted him dead. No, they want to do something more. They want to make him think. And think he does. And we think, too. It turns out that we're prisoners, too, ensnared in Poe's words, just as the narrator is locked in his cell. So, you ask, what's the deal with those strange punishments? Here are a few ideas.
Yes, it's a big, deep hole in the ground, the kind of hole into which you definitely don't want to fall. But hang on a second. What's that word we used? Fall? That's a big word for Catholics, who "fall," metaphorically speaking, every time they sin. (That first big sin, the Original, courtesy of Adam and Eve, is called the Fall with a capital "F.") And, you know where you fall if you keep "falling," so to speak? That's right: Hell. Yikes. Suddenly this pit just took on a whole new meaning.
So, it makes sense that the inquisitors want to punish our narrator by creating their own little hell. And our guy is totally aware of it: "My cognisance of the pit," he writes, "had become known to the inquisitorial agents – the pit, whose horrors had been destined for so bold a recusant as myself, the pit, typical of hell, and regarded by rumour as the Ultima Thule of all their punishments" (21).
So there you have it: "the pit, typical of hell" – "typical" in this case meaning "symbolic of" or "symbolizing." Throw in those spooky, red hot, glowing demons and, well, there you have it. H-E-double hockey sticks.
Quick note: that "Ultima Thule" Poe mentions harkens back to an old-timey geographical notion. Thule was a Latin term for a very distant place, usually to the north; in the Middle Ages, it was sometimes used to mark Greenland or Iceland on maps. Ultima means final, so "Ultima Thule," would mean the most very distant place – something really, truly extreme.
First, let's make sure we're all on the same page. If you don't know what a pendulum is, read up, and then come on back.
Now, let's look at the narrator's first description of the pendulum:
Looking upward, I surveyed the ceiling of my prison. It was some thirty or forty feet overhead, and constructed much as the side walls. In one of its panels a very singular figure riveted my whole attention. It was the painted figure of Time as he is commonly represented, save that in lieu of a scythe he held what at a casual glance I supposed to be the pictured image of a huge pendulum, such as we see on antique clocks. There was something, however, in the appearance of this machine which caused me to regard it more attentively. While I gazed directly upward at it (for its position was immediately over my own), I fancied that I saw it in motion. In an instant afterward the fancy was confirmed. Its sweep was brief, and of course slow. I watched it for some minutes, somewhat in fear but more in wonder. Wearied at length with observing its dull movement, I turned my eyes upon the other objects in the cell. (18)
To understand the passage, first you have to know how the figure of Time is "commonly represented." As Poe mentions, he's usually got a scythe. Does that remind you of anyone else? Well, it should. The figure of Time has its basis in, among other things, the Grim Reaper. Yep, the guy that brings death.
So let's take a closer look at Father Time, Usually, he's is holding a scythe, and also some kind of timekeeping device, like an hourglass. As you might expect, the hourglass symbolizes the passing of time. As for the scythe, well, think about what happens when the last grain of sand in the hourglass falls and "time runs out." Yeah.
Now, what Poe's done here is taken Old Father Time and given him a twist. At first glance, he appears to be holding a pendulum in place of his scythe. As the pendulum descends more and more, however, the narrator realizes something terrible: the pendulum, with its razor-sharp edge, is the scythe. By rolling Father Time's usual instruments (time-keeper and death-bringer) into one terrible combo, Poe creates an instrument of torture that not only counts off the seconds until death, but also actually inflicts death itself. In this way, Father Time isn't just a symbolic or allegorical figure – in the hands of the inquisitors, he is given life and power.