But the most astounding, the most amazing feature of it was, that his device was, to all intents and purposes, perpetual motion. I tried to explain this to him, to make him understand the wonder of it, but he seemed to think it a matter of course. “Do not the sun, the moon, the stars move on forever? It is the law of the gods. Why then should not the green ball move on forever, ruled by the laws of the gods?” I confess I could not find an adequate or satisfactory answer to this. Why not, to be sure? Nevertheless, to me, who had always regarded perpetual motion, or to put it better, motion without loss of energy, as an impossible visionary thing, his endlessly rotating sphere was marvelous, fascinating. I examined it, studied it from every angle, but could make neither head nor tail of it. All I knew was that it was so. Why did it remain there, a definite distance above the radioactive mineral in the stone column? What was the invisible force that permitted the sphere to revolve and rotate freely and yet held it as firmly in position as though fixed by iron bars? And why, by what law of nature was the rotation of the sphere timed to precisely twice the speed of the earth? It was inexplicable. But whatever the answer, here, in this force was a power that, properly applied, put to useful purposes, would revolutionize the mechanical world. But unless the principle could be learned, unless it could be understood and harnessed it was no more than an interesting toy. For hours, night after night, I lay awake, cudgelling my brains, formulating theories, striving to recall all I had ever learned of physics, electricity, chemistry and the other sciences; hoping somehow, by some means, to hit upon a principle or an hypothesis that would fit the conditions. And no sooner had I worked out some theory than I found it inadequate or faulty.