"It wasn't exactly that, sir." Colonel Stopford was a man of the old school: he had been an artillery officer in the Great War, and was characteristically impatient of new notions. Dick began carefully: "You'll remember, sir, old Evans claimed to have been the inventor of that shadow-breaking device that was stolen from him and sold in England." "To a moving picture company!" snorted Stopford. "I asked him what moving pictures had to do with war." "Evans was convinced that the invention would be applied to war. He claimed that it made the modern methods of military camouflage out of date completely. He said that by destroying shadows one could produce invisibility, since visibility consists in the refraction of wave lengths by material objects. "When they stole his invention, he foresaw that it would be used in war. He set to work to nullify his own invention. He told me that he had unintentionally given to the enemies of the United States a means of bringing us to our knees, since he believed that British motion picture company was actually a subsidiary of Krupp's. He worked out a method of counteracting it." "You must get him, Rennell. Even if it's all nonsense, we can't afford to let any chance go. If Evans's invention will counteract this damned invisibility business--" The telephone on the Colonel's desk rang. He picked it up, and his face assumed an expression of incredulity. He looked about him, like a man bewildered. He beckoned to the police official, who hurried to his side, and thrust the receiver into his hand. The official listened. "All right," he said. He turned to Dick and the Civil Service representative. "Gentlemen," he said, "the President has disappeared from his office in the White House, and there are grave fears that he has been kidnapped!" CHAPTER III _In the White House_ Colonel Stopford's car had been parked around the corner of the building, and within a minute the four men were inside it, Stopford at the wheel, and racing in the direction of the White House. A nod to the guard at the gate, and they were inside the grounds. At the entrance a single guard, in place of the four who should have been posted there, challenged sharply, and attempted to bar the way, not recognizing Dick or Stopford in their civilian clothes. "Where's your officer?" demanded Stopford sharply. Half-cowed by the Colonel's manner, the young recruit hesitated, and the four swept him out of the way and hurried on. The scene outside the main entrance to the White House was one of indescribable confusion. Soldiers were swarming in confused groups, some trying to force an entrance, others pouring out. Every moment civilians, streaming over the lawn, added to the number. Discipline seemed almost abandoned. From inside the building came outbursts of screams and cursing, the scuffling of a mob. "Roscoe! Roscoe!" shouted Stopford. "Where's the President's secretary? Who's seen him? Let us pass immediately!"