Measuring the Night

I planted the base of my crook against the cold limestone threshold of the lower cloister. Weaklings surrender blindly to sleep the moment darkness falls, but I measure the dark before it can dare advance. Pulling the brass hourglass from my coat, I set it upright upon a flat slate block beside a smoking ember. With a deliberate flick of my fingers, I wedged a notched iron nail into the side casing, marking the exact level where the black sand pools each quarter-turn. As the grains hissed steadily through the narrow neck, a lone cave bat darted past the fractured arch above. Let the shadows scheme; their entire night is running on my clock.