Invisible light--disembodied minds--will vibrations! Nothing there to get hold of. Were these things real or imaginary? Was Keane Clason a great inventor, or a madman? Would Philip prove to be a real or an imaginary scoundrel? Should he summon help, or go on alone? Professional pride said: wait, don't be an alarmist! With his knuckles Quest tapped the table, half expecting it to melt under his fingers. The feeling and sound of the contact gave him a peculiar start. On the farther end of the table stood a letter-box--an invitation. From his pocket Quest snatched a slip of paper, and wrote: 6 stroke 4--9:45A--Hired. If no report in 48 hours, clamp down hard. To address a stamped envelope and slip it in with the outgoing mail was the work of seconds. But he was none too quick. He had just dropped back into a lounging attitude when the door burst open and Clason flew into the room? "We must act instantly," hissed the inventor. "Philip plans to close the transaction within a day." In spite of himself, Quest jumped upright in his chair. Clason tapped him on the shoulder reassuringly. "It's all right," he smiled, "I'm ready for him. We'll make our move this afternoon and beat him by eighteen hours. "Let's see." He paused. "Oh! yes. I was about to explain to you that as soon as the will of the Agent enters the body of his Control, the latter can again transfer it into the body of still another person. "Now you understand why I advertised for a man of exceptional character? As my Agent, I want you to enter the body of Philip, and your will must be strong enough to conquer his in the battle for mastery which will begin the instant you intrude into his body. You will still be under my control, but your will must be strong enough on its own merits to overcome his. I can direct you, but your strength must be your own. That's clear, isn't it?" * * * * * "I think so," said Quest slowly. "But what becomes of me after you have frustrated Philip's plot?" "That's the easy part of the process," smiled Clason; "but naturally you feel some anxiety about it. I simply withdraw your will from Philip, return it to your own body, and pay you a reward of ten thousand dollars." "You're sure you can?" "Perfectly. I have merely to touch Philip's hand to recapture your will. Then I immerse myself in the tank with the switch at plus. The osmotic action will extract both wills momentarily from my body. But the presence of two bodies and two wills in the solution together forces a balance, and each will seeks out and enters its own body. Then you and I climb out of the tank exactly as we are this minute." "If it weren't for my belief that anything is possible," Quest shook his head, "I'd say that your claims for this invention were ridiculous."