Step by step and equation after equation the calculations and plans were gone over, until every detail was clear in each mind. Then the men bent to their tasks; behind them not only the extraordinarily complete facilities of that gigantic workshop which was the _Sirius_; but also the full power of the detachment of police--the very cream of the young manhood of the planet. Week after toilsome week the unremitting labor went on, and little by little the massive cruiser of the void became endowed with an offensive and defensive armament incredible. An armament conceived in the fertile and daring brain of a sheer genius, guided only by the knowledge that such things were already in existence somewhere; reduced to working theory by a precise, mathematical logician; translated into fields of force by the greatest known experts; powered by the indefatigable efforts of an electrical wizard; made possible by the artful mechanical devices of the greatest inventor that three worlds had ever known! Thus it was that they approached Ganymede, ready, with blanketing screens full out, save for one narrow working band, and with a keen-eyed observer at every plate. When even the hyper-critical Westfall was convinced that their preparations were as complete as they could be made with the limited information at hand, Brandon directed a beam upon the satellite and tapped off a brief message: "stevens ganymede will arrive in about ten hours direct carrier beam toward sun we can detect it and will follow it to wherever you are sirius." "ipv sirius," came the reply, "everything here, all x glad to see you thanks newton and stevens." Brandon, at the controls, scanning his screens narrowly, dropped the vessel down to within a mile or two of the point of origin of Stevens' carrier beam without incident; then spoke to Westfall, at his side, with a grin. "Nice layout the kid's got down there, Quince. It's too bad--don't look like we're going to get any action for our money a-tall. 'Sa shame, too--what's the use of wasting it, now that we've got it all made?" "We are not done yet," cautioned Westfall, and even as he spoke an alarm bell burst into strident clamor--one of their far-flung detector screens was telling the world that it had encountered a dangerous frequency. The new ultra-lights flared instantly along the line automatically laid down by the detector, and upon the closely ruled micrometer screen of Brandon's desk there glowed in natural color the image of a globular space-ship, approaching them with terrific speed. "Men all stationed, of course, Crown?" "Stationed and ready." Crowninshield, phones at his ears and microphone at his lips, was staring intently into his own plate. "Kinda think I'll do most of it from here, but you can't always tell. If they get inside my guard you all know what to do." "All x."