"It took hundreds of years, however, before the correct solution was found. It was known that certain high frequency currents would set up an interference with the gravitational waves, for it had been found in the first part of our century that gravitation was indeed a wave form, the same as light waves, or radio waves. When this interference between the two waves, namely, the gravitational waves and the electrical waves was discovered, it was found that a metallic screen charged by electric high frequency waves would indeed nullify gravitation to a certain extent. If you charged a metal netting in this fashion and you weighed yourself on a spring scale on top of the screen, insulated of course from the screen itself, your weight would be roughly diminished one-half. "In other words, about half of the gravitation had been nullified, the other half still remaining. Thus things stood until about two years ago, when I began to occupy myself with the problem. I reasoned that while we had achieved much, still much more remained to be done. Our anti-gravitational screen still let through some of the gravitational waves, or fifty percent of the energy, which we could not seem to counteract. I felt that it was not so much the effect of the current as the material of the screen which seemed to be at fault. Experimental work along this line convinced me that I was on the right track and that if ever gravitation was to be annulled in its entirety a screen of a special material would have to be evolved in order to obtain the desired results. "I finally found that only the densest material known, namely thoro-iridium, would completely stop the gravitational waves, providing that the metal screen was uninterruptedly bombarded with alpha rays which are continually emitted by radium. "The screen finally evolved was expensive to make at first, but quantity production now has very considerably lowered the price." By this time the party had found their seats in the amphitheater, and they had seated themselves. Seats were all around a ring, which did not look much different from the old-fashioned circus ring, except that it was, perhaps, a little larger. The gravitational screen, Ralph explained, was located below and could not be actually seen. The machinery, too, was located in the basement. A fine wire netting surrounded the entire arena, from top to bottom, the purpose of which became apparent later. It was an old-fashioned horse and bareback rider act. Suddenly the gravitation was cut off, and the horse rose, beating the air with his hoofs, while the rider, in a sitting position hung onto the horse with his legs. The horse and rider no longer having any weight, they could not of course entirely control their movements. Both horse and rider at times hung with their heads downwards, then sideways, until finally, by jerking, they arrived in the center of the arena. The horse had been well trained and ceased pawing the air, and his legs hung limp.