At last we came to the narrow path that wound up the side of the mountain to the splendid palaces that crowned it. We hurried; came to a great arched gate in the emerald wall, and entered. The huge, incredibly magnificent buildings were scattered irregularly about the summit, with broad spaces between them. Here and there were paved courts of the silvery metal, which must have been an aluminum bronze, but the open ground was for the most part grown up in rank thickets of the red brush. The great building showed the wear and breakage of ages. Here and there were great heaps of gleaming crystal, where wonderful edifices had fallen, with the brush grown up around them. Incredible as it may seem, I think the old civilization of Astran had possessed a science that was able to synthetize diamonds and other precious stones, in quantities sufficient even for use as building stone. Later I had an opportunity to examine bits of the fallen masonry. Towering above all, on the very peak of the mountain, was a great ruby dome, vast as the dome of St. Peter's, and mounted upon the center of the top was a huge machine that resembled nothing so much as a great naval gun, though it was made of crystal and white metal. A little group of men were gathered about it, and as I watched they swung the great tube about, and a narrow ray of pale blue light poured out of it. And down on the plain below, where the practise beam had struck, a great boulder flashed into sudden incandescence. In their exploration of the ultraviolet spectrum, our own scientists have found rays that are strangely destructive to life, and considerable progress has been made in the development of a destructive beam of wireless energy. But later I was to meet a far more terrible ray weapon than that slender blue beam. "With that," said Melvar, "our people fight off the Krimlu at night. But the Krimlu are so many that sometimes they are able to land and take our people. If only we had more of the beams! But there is no man in all Astran who knows how the light is made, or anything save that the blue light shines out to destroy when rock of a certain kind is put into the tube. Austen wished to examine it, and spoke of something he called 'radium ore' but the priests forbade. Indeed, his curiosity is one of the reasons Jorak had for driving him away." Standing about the ill-kept streets were a few of the people of the crystal city. All were of magnificent physique, and intelligent looking, white-skinned, and fair haired. All wore garments that seemed of spun metal, and gleaming crystal weapons. Most of them were hurrying along, intent on affairs of their own, but a few gathered around us almost as soon as we stepped in the gate. I felt that they were hostile to me. They questioned Melvar in a tongue that was strange to my ears; then became engaged in a noisy debate among themselves. Their glances toward me were furtive and sullen, and their eyes had the lock of men crazed by fear.