Frannie's face was very solemn though she said nothing; and I knew then that she was wondering if her brothers would be able to keep their promise. Dr. Gryce rose from his chair. "I must adjust the aural ray--Brett may need it." He had already explained this ray. A device similar to the familiar aurometer by which the aural power of the earth is measured. He had perfected an instrument for projecting into Space the invisible aura of the earth--projecting it in a tiny, very intense beam. An instrument for visualizing its characteristic bands was in the vehicle. They hoped that the ray might reach out into distant, interstellar Space; a flash of it crossing the sky as our earth rotated. And, coming back, Brett would see it, recognize it. A guide, as he came back from beyond all the universes strewn there throughout the magnitude of Space. If it could reach out there--if he saw it. My heart sank at the thoughts, doubts, which rushed upon me. Dr. Gryce set his aural projector, with its ray, invisible to the naked eye, flashing after the vehicle. Silently he returned to his seat. "Can you see them? You can still see them, Frank?" Frannie turned to me with anxious face. I could still see the vehicle. But faintly, for faster than any mail flyer it was winging its way outward. Mars--approaching its closest point to the earth now to bring a deluge of the Martian Mails--red Mars at midnight had been above us. The vehicle had gone that way; and now, visually beside the planet, they were sinking together in the western sky. The stars were paling with the coming dawn. The east flushed with it, and presently I could see the vehicle no longer. And as I turned from my instrument, I heard Dr. Gryce. "Why Frannie, girl! You're worn out! Come, it's dawn--they've vanished." Little Frannie had fallen asleep. _CHAPTER 5_ THE RETURN We did not sight the vehicle the next night; it had seemingly passed beyond range of my instrument. With the myrdoscope we hoped to catch it, but could not. The night following was overcast with clouds. But we remained awake; Dr. Gryce seemed to feel that his sons might be returning. It was pathetic to me, observing him quietly slipping away from us at intervals to wander among the wreckage of his garden, gazing anxiously upward. A week and still they had not come. What Dr. Gryce said to my Director I do not know; but he told me the Director was satisfied to have me remain away until my present business was finished. I had determined as much for myself. Not all the Directors in the Service could have taken me away from here, with Brett and Martt unheard from. Like a beacon day and night we made sure that our aural ray was flashing its beam. But would Brett see it?