The plateau ended abruptly as if cut off with a knife. The crater fell sheer away before me, stretching to the vast blue cliffs in the north, and to the line of living purple and green that marked the beginning of the eastward forests. Only a thin green line separated the abyss from the lake on the south, which, in the reflected light of the scarlet sky, horribly suggested a sea of blood, ready to flow into the pit. Undoubtedly the crater was of volcanic origin. I could not determine its depth, nor the state of its floor--it was filled with the thick crimson mist. The wavering tongues of violet fire still flickered through it, throbbing strangely, like the reflection of fires below--hinting unpleasantly of alien life. As the rich green plain vanished beneath me, and I sped high over that busy strange white city and into the haze of the abyss, an odd feeling of the wildness and the unfamiliar terror of the place stole over me again. I was very thankful for the invention of Sam's, for the thin helmet of wire gauze above my head! Suddenly a great twisting bar of green fire writhed up, like a serpent's head, from the nest of flames. It swung and coiled and twisted through the rosy mists with a slow, deliberate motion, like an incredible reptile of flame, raising its head, _looking, searching_! Despite the helmet, great fear swept my brain like a hot flame! CHAPTER XXVIII The Flaming Brain Mighty winds whipped about me. The roaring jets of steam drove the throbbing machine on over the rosy mists, and over the flickering violet flames. And I fell--dropped into the hidden pit. Vividly I saw the great writhing head of green rising above the fire-fog ahead, with that in its waving, serpentine motion that told me that its eyes were already upon me! I was certain that it was a living, sentient entity, that it was intelligent! Could my weapons avail against it? I fell through the rosy clouds. The green and purple rim of the abyss grew vague, and the blue cliffs in the north assumed a misty indistinctness. The red mist shone until it seemed that I was swimming in a fog of crimson fire. And all the while the bright beautiful face of Xenora was before me. The light of her clear violet eyes drove the strangeness and the fear from my mind, leaving only my pain at leaving her. I drove the machine mechanically, lost in a daze of grief. For ages, it seemed, I shot forward through the haze. At last I made out a bare floor of sand and rocks, pitted with circular craters. It was a good thousand feet below, and still dim in the haze. I opened the bow tubes, and the force of my fall was checked. In three minutes more, the machine struck the earth, bow first. It tore a vast hole in the sand, and rolled over twice, coming to rest on its side. Fortunately it had been built to withstand such knocks; fortunately, too, I was strapped in my cushioned seat.