Down came the little stream, with an emphasis and noise disproportioned to its size, the cause being, as Edward guessed, the distance of the fall and the fact that the rock on which it struck was not a solid foundation, but rested above a cavity. Mary waited while he listened, turning away to pluck a flower and to catch in the falling mist the colors of the rainbow. But as Edward stood, over him came a flood of thoughts; for the air was full of a weird melody, the overtone of one great chord that thrilled him to the heart. As in a dream he saw her standing there, the blue skies and towering trees above her, a bit of light in a desert of solitude. Near, but separated from him by an infinite gulf. "Forever! Forever!" all else was blotted out. She saw on his face the white desperation she had noticed once before. "You have found it," she said. "What is the tone?" "Despair," he answered, sadly. "It can mean nothing else." "And yet," she said, a new thought animating her mobile face, as she pointed into the mist above, "over it hangs the rainbow." CHAPTER XXXI. THE HAND OF SCIENCE. A feeling of apprehension and solemnity pervaded the hall when at last the old family coach deposited its single occupant, Dr. Campbell, at the gate. The colonel stood at the top of the steps to welcome him. Edward and Mary were waiting in the sitting-room. The famous practitioner, a tall, shapely figure, entered, and as he removed his glasses he brought sunshine into the room, with his cheery voice and confident manner. To Mrs. Montjoy he said: "I came as soon as the telegram was received. Anxiety and loss of rest in cases like yours are exceedingly undesirable. It is better to be informed--even of the worst. Before we discuss this matter, come to the window and let me examine the eye, please." He was assisting her as he spoke. He carefully studied the condition of the now inflamed and sightless organ, and then replaced the bandage. "It is glaucoma," he said, briefly. "You will remember that I feared it when we fitted the glasses some years ago. The slowness of its advance is due to the care you have taken. If you are willing I would prefer to operate at once." All were waiting in painful silence. The brave woman replied: "Whenever you are ready I am," and resumed her knitting. He had been deliberate in every word and action, but the occasion was already robbed of its terrors, so potent are confidence, decision and action. Edward was introduced and would have taken his leave, but the oculist detained him. "I shall probably need you," he said, "and will be obliged if you remain. The operation is very simple."