This particular instrument was equipped with every refinement known to the science of four great Solar Systems. Its exceedingly delicate needle, swinging in an almost-perfect vacuum upon practically frictionless jeweled bearings, was focused upon the unimaginable mass of the entire First Galaxy, a mass so inconceivably great that mathematics had shown--and even Crane would have stated as a fact--that it would affect that needle from any point whatever, however distant, in universal space. Seaton actuated the minute force which set the needle in motion, but it did not oscillate. For minute after minute it revolved slowly but freely, coming ultimately to rest without any indication of having been affected in the least by any external influence. He stared at the compass in stark, unbelieving amazement, then tested its current and its every other factor. The instrument was in perfect order and in perfect adjustment. Grimly, quietly, he repeated the oscillatory test--with the same utterly negative result. "Well, that is eminently, conclusively, definitely, and unqualifiedly that." He stared at Crane, unseeing, his mind racing. "The most sensitive needle we've got, and she won't even register!" "In other words, we are lost." Crane's voice was level and calm. "We are so far away from the First Galaxy that even that compass, supposedly reactive from any possible location in space, is useless." "But I don't get it, at all, Mart!" Seaton expostulated, paying no attention to the grim meaning underlying his friend's utterance. "With the whole mass of the Galaxy as its object of attachment that needle absolutely will register from a distance greater than any possible diameter of the super-universe--" His voice died away. "Go on; you are beginning to see the light," Crane prompted. "Yeah--no wonder I couldn't plot a curve to trace those Fenachrone torpedoes--our fundamental assumptions were unsound. The fact simply is that if space is curved at all, the radius of curvature is vastly greater than any figure as yet proposed, even by the Fenachrone astronomers. We certainly weren't out of our own space a thousandth of a second--more likely only a couple of millionths--do you suppose that there really are folds in the fourth dimension?" "That idea has been advanced, but folds are not strictly necessary, nor are they easy to defend. It has always seemed to me that the hypothesis of linear departure is much more tenable. The planes need not be parallel, you know--in fact, it is almost a mathematical certainty that they are _not_ parallel." "That's so, too; and that hypothesis would account for everything, of course. But how are--" "What _are_ you two talking about?" demanded Dorothy. "We simply couldn't have come that far--why, the _Skylark_ was stuck in the ground the whole time!"