"Not an awful lot. Everything built—all I've got to do is assemble it. I should be able to do it easily in a week. Hope nothing else happens—if I drag you into any more such messes as those we've just been getting out of by the skin of our teeth, I'll begin to wish that we had started out at first to drift it back to Tellus in the Hope. Let's see how much time we've got. We should start shooting one day after an eclipse, so that we'll have five days to send. You see, we don't want to point our beam too close to Jupiter or to any of the large satellites, because the enemy might live there and might intercept it. We had an eclipse yesterday—so one week from today, at sunrise, I start shooting."
"But Earth's an evening star now; you can't see it in the morning."
"I'm not going to aim at Tellus. I'm shooting at Brandon, and he's never there for more than a week or two at a stretch. They're prowling around out in space somewhere almost all the time."
"Then how can you possibly hope to hit them?"
"It may be quite a job of hunting, but not as bad as you might think. They probably aren't much, if any, outside the orbit of Mars, and they usually stay within a couple of million kilometers or so of the Ecliptic, so we'll start at the sun and shoot our beam in a spiral to cover that field. We ought to be able to hit them inside of twelve hours, but if we don't, we'll widen our spiral and keep on trying until we do hit them."
"Heavens, Steve! Are you planning on telegraphing steadily for days at a time?"
"Sure, but not by hand, of course—I'll have an automatic sender and automatic pointers."
Stevens had at his command a very complete machine-shop, he had an ample supply of power, and all that remained for him to do was to assemble the parts which he had built during the long journey from Titan to Ganymede. Therefore, at sunrise of the designated day, he was ready, and, with Nadia hanging breathless over his shoulder, he closed the switch, a toothed wheel engaged a delicate interrupter, and a light sounder began its strident chatter.
"Ganymede point oh four seven ganymede point oh four seven ganymede point oh four seven..." endlessly the message was poured out into the ether, carried by a tight beam of ultra-vibrations and driven by forces sufficient to propel it well beyond the opposite limits of the orbit of Mars.
"What does it say? I can't read code."