Philosophers have written books on the "coincidence" in appearance of the ancient Devil and the modern decadent Plutonians. The Plutonians were once numerous and far advanced in science, and no doubt they called on the Earth many times, in prehistoric days, and the so-called Devil was a true picture of those vicious invaders, who are somewhat less human than usually portrayed. What was once classed as superstition was therefore a true racial memory. Long before our ancestors came out of their caves to build houses, the Plutonians had mastered interplanetary travel--only to forget the secret until human ingenuity should reveal it once more. The modern Plutonian in that dank cave was over ten feet tall, and it is easy to see why he dominated the assemblage. His black visage was set in an evil smile; his ebony body glistened in the firelight. He held a three-pronged spear in one hand, and sat on a pile of rocks, a sort of rough throne, so that he towered magnificently above all others. He spoke the Mercurian language, although the liquid intonations came harshly from his sneering lips. "Are ye assembled, frogfolk, that ye may hear the decision of your Thinking Ones?" he asked. * * * * * A respectful peeping chorus signified assent. But in that there was a hint of unrest; even of fear. "Speak, ye Thinking One, your commands!" "Hear me first!" An old Mercurian, unusually tall, faded and dry looking, his thick hide wrinkled like crushed leather, rose slowly to his feet and stepped before the oblong stone. His back was to the Plutonian, his face to the crescent of chiefs. "The Old Wise One!" A twittering murmur went around the assemblage. "Hear the Old Wise One!" "My people, I like this not!" began the ancient. "The Lords of the Green Star[1] have dealt with us fairly. Each phase[2] they have brought us the things we wanted"--he touched his spear and a few gaudy ornaments on his otherwise naked body--"in exchange for the worthless white sap of our trees. If we longer offend the Lords of the Green Star--" [Footnote 1: In their various languages, almost all solar races call Earth "The Green Star." Although conditions on Mercury are unfavorable, Earth can be seen from the dark star, on mountain tops, during occasional dispersals of the cloud masses.] [Footnote 2: The Mercurians had no conception of time before the Earthmen came. A "phase" is the time between calls of the freight ships, and is therefore variable; but in those days it was about six or seven months.] A raucous laugh interrupted the Mercurian's feeble voice, and it echoed eerily from the walls of the chamber.