We waited perhaps an hour, with the spectroscope attached so that the vague reflected light from Zura was spread before us in its prismatic colors. And then, momentarily, a break in the swirling, turgid atmosphere of the dark little world, let us through to its bleak, blurred, dark surface. Light was coming from there; light inherent to the little world. On the spectroscope band I saw a new dark line. "Xalite!" Livingston murmured. "You see it? Unmistakable. Deposits of Xalite exist there. Xalite in quantities which to us and our needs will be enormous. So that's the destination of our exploratory flight in the _Planeteer_! It's not a question of money with us now, John. The Anglo-American Medical Research Society--and the U. S. Government Dept. of Power--have financed us for all we need." I could only gaze at him with excitement thrilling me, matching his own. All our money troubles ended. And a double purpose to our adventure now. The conquest of Interplanetary flight; and the giving to the world an element it so greatly needed. Little Dr. Livingston was bending over me, gripping me. "You realize the need of secrecy?" he murmured. "You and I, if we get this Xalite, it will make us independently rich, of course. Enough for our life's needs. But beyond that, the world will have it. Xalite, to be cheap as old-fashioned petroleum." His voice had risen with his excitement, but suddenly he lowered it again. "But John, suppose we were unscrupulous. To keep the price of Xalite up--to deal it out, only to the rich--to make ourselves fabulously wealthy at the expense of the poor--" "I see," I agreed. I wonder why my glance, like his, strayed idly to our moonlit window oval, here on the ground floor of his home? I am not the least bit psychic; there is, of course, no such thing anyway. "We'll finish up the _Planeteer_ now," Livingston was saying. "Pete Duroh and Carruthers--that's all you'll need. And as we agreed, we'll take them with us. Four of us--that's enough to man the little _Planeteer_. But nothing must be said of Xalite. You understand?" "Yes, of course." "So far as the world will know, the _Planeteer_ is starting merely on a trial flight into Space. We don't want any publicity anyway. And Duroh and Carruthers--they must know only that we're hoping we might reach this wandering little asteroid. Nothing about Xalite. That can come later. We don't want to take the least chance of this thing leaking out--" He checked himself suddenly. We both heard it--the sound of what seemed padding footsteps, retreating from our laboratory doorway. Someone furtively slinking away in the house corridor. "Why--good Lord--!" I gasped. I dashed into the dim corridor. There was nothing; and then I heard a distant outer door close. The intruder had escaped from the house. And then, from the laboratory, came Dr. Livingston's gasp: "John, look--"