"Well, it's difficult to explain. Even now I know very little about it. I can tell you WHAT it can do, but the WHY is still as much of a mystery as ever. Briefly, this new element, or maybe it's a compound, I'm not sure which, reacts in a very strange manner to light. Let me show you. That'll beat any long-winded theory I could spout." [Illustration: "That's Wonderful!" He Exclaimed] Going to the door, Tom called in his giant servant Koku, who once had been a prince in his own far-off savage land, before Tom Swift had brought him to Shopton. "What want, Master?" came a deep-toned reply, as the huge dark-skinned man, who stood a trifle over eight feet in height, entered. "Just carry outside that telescope there in the corner," requested Tom, pointing to the instrument. "Better be careful; it's a bit heavy." [Illustration: Tom's Giant Servant Koku] "Not heavy for Koku," boomed the giant. "Liftum in one hand!" Though it was not a large instrument as telescopes go, this one, with the massive iron pier upon which it was mounted, weighed not far from four hundred pounds. When Koku clamped his mighty hand about the stand he seemed to lift it as easily as a boy might raise a baseball bat or a golf club. [Illustration: Koku Lifted It Easily] "I'll never get used to his strength," murmured Ned as the boys followed the giant through the laboratory door, Tom carrying his marvelous green disk. "He is a big boy, for fair," laughed Tom. "Lucky for our prize-fighters he hasn't gone into the ring." After carefully placing the telescope where the inventor directed, Koku returned to the bench under a near-by apple tree where it was his wont to rest when he was not needed. [Illustration: Tom Carried the Green Disk] "Now what, Tom?" questioned Ned. "Surely you're not expecting to see stars in broad daylight?" "Oh, no, though it could be done," returned Tom, pointing the instrument toward the crest of a wooded hill several miles distant from Shopton. "Now we're ready. Take a peek." "Well," said Ned, peering into the eyepiece, "all I see are a few trees." [Illustration: "Take a Peek," Invited Tom] "Just stand by," directed his friend, clamping his green disk over the front lens, or objective, of the telescope and turning on the current. As before, the green stuff seemed to vanish. "Now, look again," he said. No sooner had Ned put his eye to the instrument than he gave a start. "It's magic!" he exclaimed. "Why, that hill seems as if it were right here and the view is much brighter. I can see every leaf on the trees and--yes! even a bird's nest and the little birds in it!" [Illustration: "It's Magic!" He Exclaimed] "Now maybe you have an idea as to how I propose to discover the secret of life on the planets," responded Tom calmly. "The secret? What do you mean? Surely you don't expect to see men on Mars!"