Beneath the table stood a toy airplane. The spread of its glistening, perfect wings was hardly three feet. A wonderful, delicate toy, accurate in every detail of propeller, motor and landing gear, of brace and rudder and aileron. Then he realized that it was no toy at all, but a faithful miniature of a commercial plane. A complete, tiny copy of one of the latest single-motor, cabin monoplane models. "It looks like it would fly," he said "a friend of mine his a big one, just like it! Taught me to fly it, last summer vacation. This is the very image of it!" "It will fly!" Agnes assured him, now composed enough to smile at his amazement. "I have been with the doctor to the Pygmy Planet in it. "You stand in the violet ray until you're about three inches high," she explained, "and then get into the plane. Then you fly up and into the violet ray at the point where it touches the planet, and remain there while you grow smaller. When you are the right size, all you have to do is drop to the surface, and land. To come away, you rise into the red ray and stay in it till you grow to proper size, when you come down and land." "You--you've actually done that?" he gasped. "It sounds like a fairy story!" * * * * * "Yes, I've done it," she assured him. Then she shuddered apprehensively. "And the things--the machine-monsters, Dr. Whiting called them--have learned to do it, too. One of them came down the red ray, and attacked him. The doctor had a gun--but what could he do against one of those?" She shivered. "It carried him back up the violet beam. Just a few minutes ago, I started to phone you. Then I was afraid you would be hurt--" "Me, hurt?" Larry burst out. "What about you, here alone?" "It was my business. Dr. Whiting told me there might be danger, when he hired me." "And now, what can we do?" Larry demanded. "I don't know," she said slowly. "I'm afraid one of the monsters will be back after a new victim. We could smash the apparatus, but it is too wonderful to be destroyed. And besides, Dr. Whiting may have escaped. He may be alive there, in the deserts!" "We might fly up, in the little plane," Larry proposed, doubtfully. "I think I could pilot it. If you want--" The girl's body stiffened. Her brown eyes widened with sudden dread, and her small face went pale. She slipped quickly from the stool, drawing in her breath with a sort of gasp. The hand that gripped the automatic trembled a little. "What's the matter?" Larry cried. "I thought--" she gasped, "I think I see something in the ray! The machine-monster is coming back!" Her lips tightened. She lifted the little automatic and began to shoot into the pillar of crimson fire beside the tiny, spinning globe. Larry, watching tensely, saw a curious, bird-like something fluttering about in the red ray, _swiftly growing larger_!