Regulating the Pendulum

The timber casing of the mantle clock rose along the perimeter of the room, ticking with an uneven cadence. An uncalibrated mechanism invites inefficiency. I mounted the polished marble ledge beneath it, bracing against the beveled glass door. Its small brass latch resisted, but steady leverage from my left claw released the catch. Inside hung a heavy brass disc suspended from an iron rod. I extended my right fist to steady its erratic swing, then applied precise upward pressure on the threaded knurled nut beneath the bob. It advanced two increments. When released, the rhythmic stroke struck true, resonant and balanced.