Potts tapped his forehead with a forefinger and asked, "What is a brain? You'll say it's an organ occupying the skull and forming the center of the nervous system, and the seat of intellect, or some such thing. I don't think so. It generates electricity. You know that. A nerve impulse is a wave of electricity started and conducted by a nerve cell. You can test it. You've made brain-wave patterns of some of the boys in the ward. "The brain transforms energy into thought, or thought into energy. I'm sitting here thinking and not moving my body at all. My brain is transforming electric energy into thought. You're writing, and your thoughts guide the movement of your hand. Thought into energy." Dr. Bean turned a page and continued to scribble rapidly. Potts heard Joe move and felt the big attendant's presence behind his chair. Potts said, "The ability to think improves with use, like a muscle growing stronger with use. The first time you memorize a poem, it's a hard job. If you keep on memorizing, it becomes easier, until you read a poem a couple of times and you have it. The same goes for remembering. I'll bet you can't even remember how your breakfast tasted and smelled this morning. Probably not even what you ate. "I practice remembering with all the senses. How things look and taste and smell. Exact colors, shadows, size, impressions. Think of an airplane, and you probably think of a little silver thing in the sky. Actually, an airplane is much bigger than that, so your mental picture of an airplane is all wrong. An airplane gives me a certain impression. I have it only when looking at one. Maybe it's an unrecognized sense. I have an entirely different impression when I'm looking at a horse." Dr. Bean threw down his pencil, caught his falling glasses, drew a handkerchief from his breast pocket, and polished them. "Too deep for you, Doc?" Potts inquired. "Well, just assume that my brain is a more powerful generator and transformer than any you ever saw. I've developed it by memorizing, remembering, visualizing, working problems in my head, and so on. I've been trying to make my brain take complete control of my body. The body is composed of atoms, and the atoms are electrical charges, protons and electrons. Therefore, you're nothing but electricity in the shape of a man. "By changing myself to pure thought, or pure electricity, I believed that I could escape to the past. Get away from this age where a man is suspected of insanity if he so much as mislays his checkbook or kicks his dog. People didn't used to be crazy unless they went around hacking their relatives with an ax. "I tried to meet Columbus when he rowed ashore from the _Santa Maria_. I tried to watch the Battle of Bunker Hill. I tried to lead the Charge of the Light Brigade. I tried to invent an airplane during the Civil War. I always failed, because I didn't have enough sensory knowledge of the period, and I couldn't change the past.