The gas that killed Sylvia Plath didn’t rise as she hoped lighter than air but heavier sank to the floor through cracks penetrating the lower flats there   the gas that killed Sylvia Plath left Mr Thomas comatose below neither understanding her grief nor sharing her wrath he slept breathing in the tranquil flow   the gas that killed Sylvia Plath turned her blood bright pink and thin tilted her mind down death’s slanting path leaving a residuum of cherry-red skin.