"Now we all know each other," Bayley boomed. "We're one big happy family--or are we?" He looked at Harwich significantly, a definite scowl now crinkling his heavy brows. "Harwich," he added, "we appreciate your company a lot. Only we are engaged in some pretty serious business here, and it doesn't allow us to take in outsiders." For reasons of his own, Bayley was trying to get rid of the big patrol pilot. But Harwich was inclined to be very stubborn, naturally, and faint, pleading looks from both Clara and Paul Arnold, made him doubly so, just at present. Harwich had the aspect of a very dangerous adversary in a physical encounter; his weathered features were far from beautiful, and at certain times he had a way of grinning that made him look like a good-natured devil with a hot pitchfork hid behind his back. He turned on that grin, now. "What's in that package sticking out of your coat-pocket, George?" he asked the fat printer breezily. "It's about the right size and shape to be the new Gyon condenser we need. I was going to buy one myself; but seeing that you've already done so, we might as well go to work installing it in the Penetrator apparatus." "Well, all right, Harwich," Bayley growled with some slight show of timidity. "As long as you're Paul's friend, I suppose you can stick around." "Thanks a lot, George," Harwich chuckled, as the printer set the package containing the precious Gyon condenser on a work table. The patrol pilot was almost sure he heard faint sighs of relief from the two Arnolds, as Bayley backed down. Had they come to mistrust him too, since he had been financing them? Did they feel more at ease because he, Evan Harwich, whom Bayley could never bulldoze, was their partner now too? The spaceman wondered, and he couldn't help wondering something else. On Clara Arnold's left hand, there was a diamond gleaming. An engagement ring. Bayley's? The way the latter had clung to the girl's arm, it couldn't very well be anybody else's. Could Clara, quiet and beautiful, ever love the boisterous, paunchy printer? The Arnolds were a strange family, anyway. The son was ready to sacrifice his life in an effort to reach the Forbidden Moon, where his father's ashes lay entombed. The daughter? Might she not be of the same fanatical breed? Might she not be willing to marry Bayley, so that he would supply funds for their experiments? For a moment, Evan Harwich felt a sharp, hurt ache, deep in his heart. But he fought it down. All this was none of his business. And from a heavy-glazed window slit in the ceiling of the laboratory room, a shaft of soft light from ugly Io, the Forbidden Moon, was stabbing down, appealing to his own adventurous nature. Paul had slipped on a pair of lab coveralls. He tossed another pair to the patrol pilot. "Come on! Let's get started, Evan," he urged pleasantly. "We've got a big job in front of us, and remember you said we'd get through with it before long!" * * * * *