"I suppose that I ought to be scared to death, Steve, but I'm not--I'm just too thrilled for words," Nadia answered, and the eager sparkle in her eyes bore out her words. "Can we go out now? How about air? Shall we wear suits or go out as we are? Have you got a weapon of any kind? Hurry up--let's do something!" "Pipe down, ace! Remember that we don't know any more about anything around here than a pig does about Sunday, and conduct yourself accordingly. Take it easy. I'm surprised at the gravity here. This is certainly Ganymede, and it has a diameter of only about fifty seven hundred kilometers. If I remember correctly, Damoiseau estimated its mass at about three one-hundredths that of the Earth, which would make its surface gravity about one-sixth. However, it is actually almost a half, as you see by this spring-balance here. Therefore it is quite a little more massive than has been...." "What of it? Let's go places and do things!" "Calm yourself, Ginger, you've got lots of time--we'll be here for quite a while, I'm afraid. We can't go out until we analyze the air--we're sure lucky there's as much as there is. I'm not exactly the world's foremost chemist, but fortunately an air-analysis isn't much of a job with the apparatus we carry." While Nadia controlled her impatience as best she could, Stevens manipulated the bulbs and pipettes of the gas apparatus. "Pressure, fifty-two centimeters--more than I dared hope for--and analysis all x, I believe. Oxygen concentration a little high, but not much." "We won't have to wear the space-suits, then?" "Not unless I missed something in the analysis. The pressure corresponds to our own at a height of about three thousand meters, which we can get used to without too much trouble. Good thing, too. I brought along all the air I could get hold of, but as I told you back there, if we had to depend on it altogether, we might be out of luck. I'm going to pump some of our air back into a cylinder to equalize our pressure--don't want to waste any of it until we're sure the outside air suits us without treatment." * * * * * When the pressure inside had been gradually reduced to that outside and they had become accustomed to breathing the rarefied medium, Stevens opened the airlock and the outside doors, and for some time cautiously sniffed the atmosphere of the satellite. He could detect nothing harmful or unusual in it--it was apparently the same as earthly air--and he became jubilant. "All x, Nadia--luck is perched right on our banner. Freedom, air, water, power, and coal! Now as you suggested, we'll go places and do things!" "Suppose it's safe?" Her first eagerness to explore their surroundings had abated noticeably. "You aren't armed, are you?"