High above there were ten planes flying about uncertainly. Suddenly one of these turned, heading for the ground far below, its wings screaming their protest as the motors roared, ever faster, with the gravity of the planet aiding them. There was a rending, crackling crash as the wings suddenly bent back along the sides. An instant later the fuselage tore free, rocketing downward; the wings followed more slowly--twisting, turning, dipping in mile-long swoops. The _Solarite_ shot away from the spot at maximum speed--away and up, with a force that nailed the occupants to the floor. Before they could turn, behind them flared a mighty gout of light that struck to the very clouds above, and all the landscape, for miles about, was visible in the glare of the released energy. As they turned, they saw on the plain, below a tremendous crater, in its center a spot that glowed white and bubbled like the top of a huge cauldron. Nine great planes were circling in the air; then in an instant they were gone, invisible. As swiftly the _Solarite_ darted away with a speed that defied the aim of any machine. High above the planes they went, for with his radar Arcot could trace them. They were circling, searching for the _Solarite_. The tiny machine was invisible in the darkness, but its invisibility was not revealed by the Kaxorian's radio detectors. In the momentary lull, Fuller asked a question. "Wade, how is it that those ships can be invisible when they are driven by light, and have the light stored in them? They're perfectly transparent. Why can't we see the light?" "They are storing the light. It's bound--it can't escape. You can't see light unless it literally hits you in the eye. Their stored light can't reach you, for it is held by its own attraction and by the special field of the big generators." They seemed to be above one of the Kaxorian planes now. Arcot caught the roar of the invisible propellers. "To the left, Wade--faster--hold it--left--ah!" Arcot pushed a button. Down from the _Solarite_ there dropped a little canister, one of the bombs that Arcot had prepared the night before. To hit an invisible target is ordinarily difficult, but when that target is far larger than the proverbial side of a barn, it is not very difficult, at that. But now Arcot's companions watched for the crash of the explosion, the flash of light. What sort of bomb was it that Arcot hoped would penetrate that tremendous armor? Suddenly they saw a great spot of light, a spot that spread with startling rapidity, a patch of light that ran, and moved. It flew through the air at terrific speed. It was a pallid light, green and wan and ghostly, that seemed to flow and ebb. For an instant Morey and the others stared in utter surprise. Then suddenly Morey burst out laughing.