"Our chief object was to answer those signals, but it proved heartbreaking work at first. We could not produce a radio wave of great enough length to pierce out through earth's insulating layer and across the gulf to Mars. We used all the power of our great windmill-dynamo hook-ups, but for long could not make it. Every few hours like clockwork the Martian signals came through. Then at last we heard them repeating one of our own signals. We had been heard! "For a time we hardly left our instruments. We began the slow and almost impossible work of establishing intelligent communication with the Martians. It was with numbers we began. Earth is the third planet from the sun and Mars the fourth, so three represented earth and four stood for Mars. Slowly we felt our way to an exchange of ideas, and within months were in steady and intelligent communication with them. "They asked us first concerning earth, its climates and seas and continents, and concerning ourselves, our races and mechanisms and weapons. Much information we flashed out to them, the language of our communication being English, the elements, of which they had learned, with a mixture of numbers and symbolical dot-dash signals. "We were as eager to learn about them. They were somewhat reticent, we found, concerning their planet and themselves. They admitted that their world was a dying one and that their great canals were to make life possible on it, and also admitted that they were different in bodily form from ourselves. "They told us finally that communication like this was too ineffective to give us a clear picture of their world, or vice versa. If we could visit Mars, and then they visit earth, both worlds would benefit by the knowledge of the other. It seemed impossible to me, though I was eager enough for it. But the Martians said that while spaceships and the like were impossible, there was a way by which living beings could flash from earth to Mars and back by radio waves, even as our signals flashed!" * * * * * Randall broke in in amazement. "By radio!" he exclaimed, and Milton nodded. "Yes, so they said, nor did the idea of sending matter by radio seem too insane, after all. We send sound, music by radio waves across half the world from our broadcasting stations. We send light, pictures, across the world from our television stations. We do that by changing the wave length of the light-vibrations to make them radio vibrations, flashing them out thus over the world, to receivers which alter their wave-lengths again and change them back into light-vibrations.