I understood the basic principle of this that he was explaining--that now when this electronic current which he had captured and controlled was applied to our physical body, the vibration rate of every smallest and most minute particle of our physical being was altered. There is so little in the vast scale of natural phenomena of which our human senses are cognisant! Our eyes see the colors of the spectrum, from red to violet. But a vast invisible world of color lies below the red of the rainbow! Physicists call it the infra-red. And beyond the violet, another realm--the ultra-violet. With sound it is the same. Our audible range of sound is very small. There are sounds with too slow a vibratory rate for us to hear, and others too rapid. The differing vibratory rate from most tenuous gas to most substantial solid is all that we can perceive in this physical world of ours. Yet of the whole, it is so very little! This other realm to which we were now going lay in the higher, more rapid vibratory scale. To us, by comparison, a more tenuous world, a shadow realm. I listened to Derek's words, but my mind was on the practicality of what lay ahead. An explorer, standing upon his ship, may watch his men bending the sails, raising the anchor, but his mind flings out to the journey's end.... * * * * * We were soon ready. Derek wore his jaunty uniform, I wore my ordinary business suit. A magnetic field would be about us, so that in the transition anything in fairly close contact with our bodies was affected by the current. Derek said, "I will go first, Charlie." "But, Derek--" A fear, greater than the trembling I had felt before, leaped at me. Left here alone, with no one on whom to depend! He spoke with careful casualness, but his eyes were burning me. "Just sit there, and watch. When I am gone, turn on the current as I showed you and come after me. I'll wait for you." "Where?" I stammered. He smiled faintly. "Here. Right here. I'm not going away! Not going to move. I'll be here on the couch waiting for you." Terrifying words! He had lowered the couch, bending out its short legs until the frame of it rested on the board floor. He drew a chair up before it and seated me. He sat down on the couch. He said, "Oh, one other thing. Just before you start, put out the light. We can't tell how long it will be before we return." Terrifying words! His right hand was on his left wrist where the tiny switch was placed. He smiled again. "Good luck to us, Charlie!" Good luck to us! The open road, the unknown! I sat there staring. He was partly in shadow. The room was very silent. Derek lay propped up on one elbow. His hand threw the tiny switch. There was a breathless moment. Derek's face was set and white, but no whiter than my own, I was sure. His eyes were fixed on me. I saw him suddenly quiver and twitch a little. I murmured, "Derek--"