"From the light side of this Moon," was the reply. "You already know that the people there are adventurous and love to do anything or go anywhere to satisfy their explorers' nature. Whenever the Martonians plan to establish a new outpost in space, these tribes are always eager to go there to maintain the post. As you heard, the post on the Moon you have just seen was established five hundred years ago, at which time one whole tribe was moved there from here. By staying there steadily they have increased their population. Those on the light side have a life span of only about three hundred fifty years, so none of those originally taken there are still living. However, should any of those living there, either on the light side or the dark side, ever desire to come to this Moon or go to Mars, either to visit or to live, they may do so, for one of the Martonian ships would take them. This has always been the Martonian policy. Some have taken advantage of this privilege and come here to stay, but most of them have come now and then merely to visit. The same is true about going to Mars." Here he turned smiling to our chieftain companion from the light side and said, "Right?" Our friend smilingly nodded an assent. His questions along that line answered, Dr. Johnston next wanted to know how far this telescope has penetrated into space. Here the scientist marked on a blackboard in symbol drawing, indicating that its limits haven't yet been reached and that its power is being steadily increased by new instruments being added onto it. "From what you have seen and explored, are all planets of all systems outside of our own system, as well as within it, inhabited?" broke in George. "Yes," was the prompt reply, "of trillions upon trillions of planets known to us now, we know of no planet anywhere that is not partially, if not densely inhabited. In our own system, planet Venus is fifty thousand years ahead of Earth and twenty thousand years ahead of Mars in advancement. Your Earth, being the third nearest planet to the sun, is one of the oldest planets in our system." "If that is true and the Earth is so old, why haven't we got the things that the Martonians have?" queried Bob, still fascinated by what he had seen of their space ships.