The big machine began to hum a deep-throated drone that deepened and strengthened until I could feel it shaking the floor under my feet with each colossal pulse of energy. I wondered about the sympathetic vibrations you read about in the Sunday supplements. Might it not shake the walls down around our ears? But Dampier didn't seem worried. And then I forgot it, for a shadow was beginning to form in the space between the coils. That's all it was at first--a shadow, the size of a big red polished apple. I could hardly be sure it was there, but there was something queer about the way light acted that showed me where it was. Things behind it disappeared, smothered out by something that wasn't really darkness; and then suddenly it began to shine. You've seen bubbles of air under water, shining like quicksilver. Well, it was like that. It was flawless, without texture, intangible and shimmering. It was not the thing itself we saw, but the things reflected in it--a little, twisted, shining world swimming in the heart of that ball of distorted space. Peering closer, I saw that the coils which shaped it were glowing with an eerie, frosty white light. I stared, fascinated, and by what? By a half-invisible bubble, like an indoor baseball, conjured up by some legerdemain to make fools of us! It was nonsense! I jerked my eyes away--and saw them. Three men with guns stood on the little stair, watching us. They were gentlemen, polished, clever gentlemen adroit at the art of death. Their guns were of the kind which Middle-Europe gives to its officers, and their faces were Middle-European faces. They were in formal dress, and one of them held his gloves in his left hand. Dampier had seen them before I, reflected in the shining sphere. He turned, his back against the control-panel, his white teeth gnawing like a rat's at his black beard. The madness was back in his glittering eyes; madness of a trapped beast. "So!" he whispered. "Now we shall meet." They came down the stairs, one after the other. How they had cut their way into that Gibraltar of a house I will never know. They may have been working for days and weeks to break through Dampier's defenses. But they were there. Resistance was futile. Even Dampier realized that. The three guns urged us back against the wall. Deft fingers searched us but found nothing. The three men stepped back to the foot of the little stair, their guns raised, like a firing squad waiting for the signal. And then, above them, I saw the smiling face of Wilhelm Friedrich Nebel, Ambassador from Middle-Europe.