A True Measure

I steadied the brass column of the small apothecary balance on the worktable before disengaging the central arrestment. Damp river air will dull a fulcrum over time, introducing a bias of half a grain—a negligence that would ruin any delicate compounding. Supporting the upright with my left hand, I guided the slender tip of my wand to shift the miniature brass rider along the notched beam. The needle swung in slow, diminishing arcs before settling dead center against the ivory index. Both pans now hang in absolute equilibrium. Yesterday's dried lichen can now be portioned without the slightest margin of error.