"Not necessarily--there may well be different types, each struggling toward civilization. They certainly are on Venus, and they once were on Mars." "Why haven't we seen anything like that before, in all these months? Things have been so calm and peaceful that we thought we had the whole world to ourselves, as far as danger or men were concerned." "We never saw them before because we never went where they lived--you were a long ways from your usual stamping-grounds, you know. That animal-vegetable flower is probably a high-altitude organism, living in the mountains and never coming as low as we are down here. As for the savages--whatever they are--they probably never come within five kilometers of the falls. Many primitive peoples think that waterfalls are inhabited by demons, and maybe these folks are afflicted the same way." "We don't know much about our new world yet, do we?" "We sure don't--and I'm not particularly keen on finding out much more about it until we get organized for trouble, either. Well, here we are--just like getting back home to see the 'Hope,' isn't it?" "It _is_ home, and will be until we get one of our own on earth," and after Stevens had read his meters, learning with satisfaction that the full current was still flowing into the accumulators, he began to cut up the meat. "Now that you've got the power-plant running at last, what next?" asked Nadia, piling the cuts in the freezer. "Brandon's ultra-radio comes next, but it's got more angles to it than a cubist's picture of a set of prisms; so many that I don't know where to begin. There, that job's done--let's sit down and I'll talk at you awhile. Maybe between us we can figure out where to start. I've got everything to build it lined up except for the tube, but that's got me stopped cold. You see, fields of force are all right in most places, but I've got to have one tube, and it's got to have the hardest possible vacuum. That means a mercury-vapor super pump. Mercury is absolutely the only thing that will do the trick and the mercury is one thing that is conspicuous by its absence in these parts. So are tungsten for filaments, tantalum for plates, and platinum for leads; and I haven't found anything that I can use as a getter, either--a metal, you know, to flash inside the tube to clean up the last traces of atmosphere in it." "I didn't suppose that such a simple thing as a radio tube could hold you up, after the perfectly unbelievable things that you have done already--but I see now how it could. Of course, the tubes in our receiver over there are too small?" "Yes, they are only receiver and communicator tubes, and I need a high-power transmitting tube--a fifty-kilowatter, at least. I'd give my left leg to the knee joint for one of those big water-cooled, sixty-kilowatt ten-nineteens right now--it would save us a lot of grief." "Maybe you could break up those tubes and use the plates and so on?"