Stern rigged a tripod for the powerful field-glasses he had rescued from the Metropolitan Building, and by an ingenious addition of a wooden tube and another lens carefully ground out of rock crystal, succeeded in producing (on the right-hand barrel of the binoculars) a telescope of reasonably high power. With this, of an evening, he often made long observations, after which he would spend hours figuring all over many sheets of the birch bark, which he then carefully saved and bound up with leather strings for future reference.
In Van's set of encyclopedias he found a fairly large celestial map and thorough astronomic data. The results of his computations were of vital interest to him.
He said to Beatrice one evening: "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--"