"Do you mean to tell this court that you can adjust the dials and gadgets on this thing and see what I was doing last week or the week before?" I tried to be cautious. "If it's plugged in." "Okay, we'll plug it in." He invited me to step down and turn on the switches. I looked at Slim. He nodded. After all, there was nothing else to do. I went. Some of the tubes crackled and then settled down to a steady green glow, and one bank showed purple. Then the lawyer said, "Now, do you mean to tell me you can tune this contraption in on a man's brain and find him anywhere in the past?" He sounded completely skeptical. "Within three months," I said defiantly. "For instance, you testified that Tom Ellingbery was riding the roller coaster on the night of July the Fourth with the girl who has been named in this case. You saw this on this screen?" "Yes." "Can you tune it in again?" * * * * * Well, I knew this was all preliminary. It would take something absolutely dynamic to convince Judge Monday that the Brain-Finder was the real thing and not a fake. So I wasn't worrying--yet. "Yes," I said, and set the dials to Tom Ellingbery's brain-waves. I picked up Tom and the bleached blonde just as they stepped into the roller-coaster car, and followed them around the ride. It wasn't very sensational; she screamed and hid her eyes and grabbed Tom around the neck. Standard technique. Then the lawyer said, "Can you pick up your own brain-wave on this thing?" "Yes." "What were you doing on the night of July the Fourth?" "I was--" I swallowed. "I was riding the roller coaster." I think somebody snickered. "Can you show us?" "Yes," I said cautiously. I began to adjust the dials. Again the amusement park flickered over the ground glass, as seen through my eyes. I was in line. I put my money on the counter to buy a ticket. I saw a slim white hand reach up to the window from my left and I started to turn. Then it hit me! That gorgeous blonde! That girl who had thrown her arms around me in the car a minute later. That was Swanberg's wife. I looked around at them in the court-room. I knew what was happening on the screen. I hadn't looked at her face until she got into the car after me. Mrs. Swanberg was leaning over, now, watching the screen. One arm was slipped through the landlord's elbow and she was surreptitiously but affectionately patting the back of his hand. Swanberg himself looked completely blissful. What had she been out there alone for, that night? Well, no telling. Maybe he'd been out of town and she'd felt like doing something childish. Certainly there was no meanness or deceit in her face. She was in love with him. And he, in spite of all his austerity, was obviously in love with her.