During the following days I questioned Naro constantly as to the doings of his sister, and of the Astranians, but I was able to elicit no very satisfactory information, except that none of the Krimlu had been seen for several days, and that the headmen of the nation were beginning to expect a raid in force. Also I persuaded him to keep a very close watch on the movements of Melvar, and to come to me at once if Jorak made any attempt to get her into his power, or if the sacrificial ceremony was begun with the victim unselected. During the interminable periods when I was alone, I was driven almost insane by the monotony and the anxiety of my existence. But I had my scientific equipment, and I had the boy to bring me a few assorted fragments of the crystal building stone, which I tested and found to be real gems, of several varieties. Many of the gems were simple enough in chemical formula, and composed of the most common elements, so the synthesis of them by scientific means is not unreasonable. For example, it is a well-known fact that diamond is just a crystal form of carbon, which element occurs in three allotropic forms. Those three forms are diamond, graphite, which also crystallizes, and amorphous carbon, of which charcoal is a form. Since carbon occurs in the air in carbon dioxide, it is not impossible that latterday science would be able to manufacture diamonds from the air. Sapphires are aluminum oxide, or alumina, colored with a little cobalt, and rubies are composed of the same oxide, with a trace of chromium, to which the color is due. A clay-bed would supply an inexhaustible amount of the elements needed for the synthesis of these gems, and I think the people of old Astran had been able to accomplish it. I examined the little glow-lamp, too, and found it to be simply a crystal bottle filled with the moist crushed leaves of the red plants, which formed a culture of some kind of luminous bacteria. On the seventh night, when the pale ray of daylight that filtered down into my hiding place was dimmed, Naro burst into the chamber, panting, and wild-eyed with terror. His crystal sword was gone, his metallic mantle was torn, and blood was falling, drop by drop, from a deep scratch on his arm. He thrust into my hand a tattered scrap of paper, evidently the flyleaf of a book. On it, in an ink that I took at first to be blood, although it was probably the juice of the red plants, the following words were formed in hastily drawn printing characters. "Winfield, There is no hope. The priests will offer a gift to the Purple Sun. I am the victim. Already I am in the hands of Jorak. I am sorry, for I loved you. It may be that I can give this to Naro, who could take it to you. The Krimlu are coming tonight. Already their lights flicker above the mist. In the morning my brother will take you to the gate, and you may escape. If only it had been one night later we might have all been away together. Farewell.