Tony ran over this strange circumstance mentally. His mental processes were active beneath, though dazed on the surface. His desk had stood there. While looking fully at it, all his senses intact, he had seen it vanish, and for a moment there had been nothing in its place. While he stared directly at the empty space from which the desk had disappeared, another desk had materialized there, like a flash. Perhaps, there had been a sort of jar, a tremor, of the floor and of the air, of everything. But the point was that his own desk, at which he had been working one moment, had suddenly vanished, and at the next moment another desk had appeared in its place. And what a desk! The one that now stood there was smaller than his own palatial one, and shabbier. A raw, unpleasant golden-oak, much scratched and scuffed. Its top was heaped and piled full of books and papers. In the middle of it stood a photograph of a girl, framed in red leather. Irresistibly, the sunny beauty of the face, the bright eyes, the firm little chin, the tall forehead topped by a shining mass of light curly hair, drew Tony's first glance. For a few moments his eyes rested delightedly on the picture. In a moment, however, Tony noticed that the books and papers on the desk were of a scientific character; and such is the nature of professional interest, that for the time he forgot his astonishment at how the desk had got there, in his absorption in the things heaped on top of it. Perhaps it isn't fair to give the impression that the desk was in disorder. It was merely busy; just as though someone who had been deeply engaged in working had for the moment stepped away. There was a row of books across the back edge, and Tony leaned over eagerly to glance at the titles. "'Theory of Parallels,' Lobatchevsky; 'Transformation of Complex Functions,' Riemann; 'Tensors and Geodesics,' Gauss," Tony read. "Hm--old stuff. But here's modern dope along the same line. 'Tensors,' by Christoffel; 'Absolute Differential Calculus,' by Ricci and Levi Civita. And Schroedinger and Eddington and D'Abro. Looks like somebody's interested in Relativity. Hm!" * * * * * He bent over, his constantly increasing interest showing in the attitude of his body; he turned over papers and opened notebooks crowded full of handwritten figures. Last of all he noted the batch of manuscript directly in front of him in the middle of the front edge of the desk. It was typewritten, with corrections and interlineations all over it in purple ink.