"Presently we arrived at what we thought was the draw down which the two crawling figures had vanished. Instead of finding what we expected we actually encountered a saucer-like crater which I assumed at once to have been the one from which the lava forming the Manalava Plain had erupted. We stood on the brink of the yawning pit and noted that in the center, surrounded by overhanging lava forming a circular cave, brilliant with a green phosphorescent glow, was a pool probably a hundred feet in width. The pool seemed as alive as that grotesque cactus with its restless tentacles. "The pale green that filled it, with its ghostly hue, reminded us of the spring at which we found the Lane album. The material shimmered and scintillated and even from our height we felt a terrific heat that must have come from the stuff. There was a powerful odor coming from it, too, sweet and nauseating. The glare from the pool seemed to burn our skin even at the distance we stood from it. Nowhere was there a sign of the mysterious crawling figures--the man and the woman, although under our feet were the marks of a ragged trail. "'Good Lord, Sands!' I cried, 'that stuff could be radium!' "Sands looked at me with a puzzled frown. "'Hell!' he expostulated, 'there's not that much radium in the whole world and we wouldn't know it if we seen a lake of it. Looks like some green salt solution to me and indications point to some funny deposits here! What's that unearthly noise?' "I cupped my hands behind my ears to catch the sound that Sands had heard. My hair literally stood on ends. Spooky? Lord! I couldn't have moved a foot if I wanted to. I was glued to the spot. The weird sound, like the low moan of a woman in mortal agony, issued from the circular cave surrounding the luminous pool. It grew louder until the Manalava Plain groaned under the tumult. The sounds penetrated to the core of the brain and seemed to beckon us down into the crater. Sands was swaying to and fro as he stood on the slight parapet overlooking the crater, in perfect rhythm to the tempo of the devilish sounds. I felt that I too was keeping the same accompaniment and it was with an effort that I broke the spell. "My hand dropped to my gun butt. I tore it out of its holster and fired rapidly, thumbing the hammer, into the pool. Sands yelled. Like a living fountain, long columns of luminous green and red and violet flame shot up to the parapet. Simultaneously we both leaped back. The air seemed alive with some mysterious vibrations. Finally it died away and the tumult issuing from the circular cave settled down to a low, steady hum. We once again stood on the crater's escarpment and looked within. The pool was glittering restlessly.