She started. "Cantor?" What did he know about Cantor? Had he discovered something about the man that she herself had been unable to discover? Had he definitely placed Cantor as a German spy, a master of spies?... If so, he must know about her father, too. "Cantor?" she repeated. "What do you know about Mr. Cantor?" "Nothing. But I must know. Was it he?" "I can tell you nothing about him," she said. "But I can warn you. Don't trust him. If you have anything you value, keep it out of his hands. Don't let him near your motor.... Keep him away from you.... Don't trust that man." He bowed his head. "You've answered me," he said, in a stifled voice.... So it was Cantor. The man to whom he owed this agony was Cantor.... He ground his teeth. Then he grew gentle with her. "Remember, Hildegarde, that I love you. It isn't a little love that would be afraid of anything. Nothing would matter to it. Will you remember that, and if ever you change--if anything changes you--will you know that I'm waiting for you?" He lifted her hand and kissed it. "Let me out, please," he said. "I--I can't stay near you.... It's too much for me." "Good-by, Potter," she said, softly. "I-- Oh, how I wish I might come to you!" The car stopped and Potter alighted. He stood on the curb, looking after Hildegarde, until the car turned a corner and disappeared. "Cantor," he said to himself, and whispered the name over and over. "Cantor.... Cantor.... Cantor...." Could Mr. Cantor have sensed the furnace that raged in Potter's brain it might have caused him certain uneasiness. Potter walked and walked until he regained some semblance of calmness. Then he turned his footsteps toward the hotel. In the corridor he met numerous men in uniform and vaguely envied them. "They're going," he said. "It's luck.... Maybe the biggest luck would be to go--and not come back." CHAPTER XVIII It was July before Potter Waite saw Detroit again for more than a few hours. His business lay in Washington, and in Washington he remained. It was his privilege to hear from the gallery the most momentous utterance ever to issue from the New World when Mr. Wilson guided this country down into the abyss of war. Later he met on equal terms with the great automobile minds of the country when they were called together to give to their flag the dearly bought knowledge of motor construction which was their most precious possession. He saw his own motor placed before him, and waited in a sort of white glow of eagerness for what would be the outcome of that herculean labor performed by two men called to give to America the motor needed for her mighty air fleets. That moment when he saw his year's work had not been in vain was one of the splendid moments of his life, for his motor had been the basis upon which those engineers had worked, and from it they developed the perfect thing.