Detis raised his head proudly and his frown softened at the sound of dainty footsteps. His voice was a caress as he replied. A vision of feminine loveliness stood framed in the doorway and the visitors rose hastily from their seats. Carr gazed into eyes of the deepest blue he had ever seen. Small in stature though this girl of Europa was--not more than five feet tall--she had the form of a goddess and the face of an angel. He was flushing to the roots of his hair. Could feel it spread. What an ass he was anyway! Anyone'd think he'd never seen a woman in all his thirty-five years! "My daughter, Ora, gentlemen," said Detis. The girl's eyes had widened as she looked at the huge Martian with the funny black box on his back. They dropped demurely when turned to those of the handsome Terrestrial. "Oh," she said, in Cos, "I didn't know you had callers." CHAPTER VI _Vlor-urdin_ The time passed quickly in Pala-dar, city of the golden domes. Detis spent many hours in the laboratory with his two visitors and the fair Ora was usually at his side. She was an efficient helper to her father and a gracious hostess to the guests. The amazement of the visitors grew apace as the wonders of Europan science were revealed to them. They sat by the hour at the illuminated screen of the rulden, that remarkable astronomical instrument which brought the surfaces of distant celestial bodies within a few feet of their eyes, and the sounds of the streets and the jungles to their ears. It was no longer a mystery how the language of Cos had become so familiar to these people. They learned of the origin of the races that inhabited Europa and Ganymede. Ages before, it was necessary for the peoples of the then thickly populated Jupiter to cast about for new homes due to the cooling of the surface of that planet. Life was becoming unbearable. In those days there were two dominant races on the mother body, a gentle and peaceful people of great scientific accomplishment and a race of savage brutes who, while very clever with their hands, were of lesser mental strength and of a quarrelsome and fighting disposition. Toward the last the population of both main countries was reduced to but a few survivors, and the intelligent race had discovered a means of traversing space and was prepared to leave the planet for the more livable satellite--Europa. Learning of these plans, the others made a treaty of perpetual peace as a price for their passage to another satellite--Ganymede. The migration began and the two satellites were settled by the separate bands of pioneers and their new lives begun. * * * * *