Now and then one of the mechanical moles would cease its labors, overcome by the concentrated fury of destruction centered upon it. Its shattered remnants would be withdrawn and shortly, repaired or replaced, it would be back at work. But it was not the defenders who had suffered most heavily. The fortress was literally ringed about with the shattered remnants of airships, and the riddled hulls of more than a few of those mighty globular cruisers of the void bore mute testimony to the deadliness and efficiency of the warfare of the invaders. Even as they watched, one of the spheres, unable for some reason to maintain its screens or overcome by the awful forces playing upon it, flared from white into and through the violet and was hurled upward as though shot from the mouth of some Brobdingnagian howitzer. A door opened, and from its flaming interior four figures leaped out into the air, followed by a puff of orange-colored smoke. At the first sign of trouble, the ship next it in line leaped in front of it and the four figures floated gently to the ground, supported by friendly attractors and protected from enemy rays by the bulk and by the screens of the rescuing vessel. Two great airships soared upward from back of the lines and hauled the disabled vessel to the ground by means of their powerful attractors. The two observers saw with amazement that after brief attention from an ant-like ground-crew, the original four men climbed back into their warship and she again shot into the fray, apparently as good as ever. "What do you know about that!" exclaimed DuQuesne. "That gives me an idea, Loring. They must get to them that way fairly often, to judge by the teamwork they use when it does happen. How about waiting until they disable another one like that, and then grabbing it while its in the air, deserted and unable to fight back? One of those ships is worth a thousand of this one, even if we had everything known to the Osnomians." "That's a real idea--those boats certainly are brutes for punishment," agreed Loring, and as both men again settled down to watch the battle, he went on: "So this is war out this way? You're right. Seaton, with half this stuff, could whip the combined armies and navies of the world. I don't blame Brookings much, though, at that--nobody could believe half of this unless they could actually see it, as we are doing." "I can't understand it," DuQuesne frowned as he considered the situation. "The attackers are Kondalians, all right--those ships are developments of the _Skylark_--but I don't get that fort at all. Wonder if it can be the strangers already? Don't think so--they aren't due for a couple of years yet, and I don't think the Kondalians could stand against them a minute. It must be what is left of Mardonale, although I never heard of anything like that. Probably it is some new invention they dug up at the last minute. That's it, I guess," and his brow cleared. "It couldn't be anything else."