Slender tentacles of purple fire coiled around me. They touched me. Their touch was cold--cold flame! But it burned! I felt a tingling sensation of pain--unutterably horrible. The contact with that monster shocked like electricity--but it was as cold as space! I shrieked as I fell! With my last energy, I sent out my fist at that flaming scarlet core. My arm went through it, cut it! Then I have a confused impression of cries of agony and terror, of men cursing, screaming, falling. There were pistol shots, shouts, and dreadful sobbing gasps. I sat up, and saw that the room was full of writhing, dying men! Corpses weirdly splashed with red! And the purple thing lay before me on the floor, inert and limp, with the fire in it fading. Still it was unspeakably horrible. Then I heard Ellen cry out, calling my name! I ran on in the room. Ellen stood at the bars of a flimsy little door back of the desk at which the men had been seated. "Bob," she cried, "I heard you! I knew it was you!" I smashed the door with one of the rifles. The girl ran out to me, with Bill and the Doctor at her heels. The Doctor took in what had happened. "The r-r-r-ray made slow p-p-p-p-poisons in their blood. Not adjusted right. It can upset the chemical equilibrium of the body in a thousand ways. But let's get b-b-b-back in the other ship before something happens." We got through the manhole. I closed it again and unfastened the clamps that held us to the other ship, while the Doctor and Bill ran forward into the pilot's compartment. I felt the vessel rise. Ellen and I stood by one of the round ports. We saw the weird red city drop away below us. Soon the flat, desolate purple desert was slipping along beneath us, with the green-gray earth visible through it, so far below. And still there was no movement from the city. We were several miles away before I saw the red ships rise in long lines from their places on the landing deck. Our flight had been discovered! And then I saw the great dome moving, the slender tube pointing at us. They were going to use the ray! The Doctor's voice came from the forward compartment. "I was afraid something would happen to the p-p-p-p-plans. You know I told you that I almost had an atomic explosion of the molten Vernonite electrode. The specifications on the blue print were almost right--almost--" A great flare of white light burst from the transparent dome. A blaze of blinding incandescence blotted out the scarlet metal city. After a long moment it was gone, and we could see again. The city in the sky was no more! There was only a vast ragged hole in the purple plain! That was perhaps the most terrific explosion of history, but we neither felt nor heard it, for we were above the air. * * * * *