Meanwhile, his psychology was undergoing strange alterations; the more I came to appreciate the actual conditions he was living under, the more apparent it seemed to me that he must have a cast-iron mental stamina to maintain sanity at all. But he not only did that; he began to recover normal strength, and to be irked unbearably by his constant confinement. So it came about that he began to venture a little at a time from his room, wandering about on the ceiling of the rest of the house. However, he could not yet look out of windows, but sidled up to them with averted face to draw any blinds that were up. As he grew increasingly restless, we all felt more and more that the thing could not continue as it was; some way out must be found. We had many a talk with Grosnoff, at last inducing him to speak about the still half-formed theory which he had dimly conceived at the first. "For a good many decades," he said, "there have been a few who regarded the close analogies between magnetism and gravitational action as symptomatic of a concealed identity between them. Einstein's 'Field Theory' practically proves it on the mathematical side. Now it is obvious that if gravitation is a form of magnetism--and if so it belongs to another plane of magnetic forces than that which we know and use--then the objects on a planet must have the opposite polarity from that of the planet itself. Since the globe is itself a magnet, with a positive and negative pole, its attraction power is not that of a magnet on any plane, because then the human race would be divided into two species, each polarized in the sign opposite to its own pole; when an individual of either race reached the equator, he would become weightless, and when he crossed it, would be repelled into space." "Lord!" I said. "There would be a plot for one of your scientific fiction writers!" * * * * * "I can present you with another," said Dr. Grosnoff. "How do we know whether another planet would have the opposite sign to our own bodies?" "Well," I chuckled, "they'll find that out soon enough when the first interplanetary expedition tries to land on on of 'em!" "Hmf!" grunted the medico. "That'll be the least of their troubles!" "But you said the polarity couldn't be that of a magnet; then what?" "Don't you remember the common pith ball of your high school physics days? An accumulation of positive electricity repels an accumulation of negative--if indeed we can correctly use 'accumulation' for a negativity--and it is my idea that the earth is the container of a gigantic accumulation of this meta--or hyper-electricity which we are postulating; and our bodies contain a charge of the opposite sign."