A sturdy, brick-built furnace in the corner of a 19th-century Parisian laboratory. The bricks are darkened and sooty from years of use, with scorched marks around the opening. The firebox opening emits a faint, flickering orange-red glow, casting warm, uneven light and dramatic shadows. The furnace has a simple, heavy cast-iron door and perhaps a small, sooty chimney pipe extending upwards.