"Do you know, that wandering black patch in the sky moves in a regular orbit of its own? It's a solid body, dark, irregular in outline, and certainly not over five hundred miles above the surface of the earth." "What can it be, dear?" "I don't know yet. It puzzles me tremendously. Now, if it would only appear in the daytime once in a while, we might be able to get some information or knowledge about it; but, coming only at night, all it records itself as is just a black, moving thing. I'm working on the size of it now, making some careful studies. In a while I shall probably know its area and mass and density. But what it is I cannot say--not yet." They both pondered a while, absorbed in wonder. At last the engineer spoke again. "Beta," said he, "there's another curious fact to note. The axis of the earth itself has shifted more than six degrees, thirty minutes!" "It has? Well--what about it?" And she went on with her platting of reed cordage. "You don't seem much concerned about it!" "I'm not. Not in the least. It can shift all it wants to, for all of me. What hurt does it do? Doesn't it run just as well that way?" Stern looked at her a moment, then laughed. "Oh, yes; it runs all right," he answered. "Only I thought the announcement that the pole-star had thrown up its job might startle you a bit. But I see it doesn't. So far as practical results go, it accounts for the warmer climate and the decreased inclination to the plane of the ecliptic; or, rather, the decreased--" "Please, please, don't!" she begged. "There's nothing really wrong, is there?" "Well, that depends on how you define it. Probably an astronomer might think there was something very much wrong. I make it that the orbit of the earth has altered its relative length and width by--" "No figures, Allan, there's a dear. You know I'm awfully bad at arithmetic. Tell me what it means, won't you?" "Well, it means, for one thing, that we've maybe spent a far longer time on this earth since the cataclysm than we even dare suspect. It may be that what we've been calculating as about a thousand years, is twice that, or even five times that--no telling. For another thing, I'm convinced by all these changes, and by the diminution of gravity and by the accelerated rate of revolution of the earth--" "Allan dear, please hand me those scissors, won't you?" Stern laughed again. "Here!" said he. "I guess I'm not much good as a lecturer. But I tell you one thing I'm going to do, and that's a one best bet. I'm going to have a try at some really big telescope before a year's out, and know the truth of this thing!" "A big telescope! Build one, you mean?" "Not necessarily. All I need is a chance to make some accurate observations, and I can find out all I need to know. Even though I have been out of college for--let's see--" "Fifteen hundred years, at a guess," she suggested.