"They haven't been nabbed yet.... And say, Harker, I want more for my money out of you. The last week your crowd hasn't earned its salt. If the Waite plant isn't better taken care of, we'll have somebody else in charge." "It's a tough job. That young Waite has the men buffaloed. Now we have to look out for the spotters and for every man in the place. They're all on the watch. It's a wonder we pull off as much as we do." Philip passed over a number of bills. "Here," he said. "Now sign the receipt. The boss is systematic." Potter could scarcely credit his senses. Here were efficiency and system indeed. He reflected an instant on the peculiarity of the German mind that insisted upon system even in its corps of spies, upon receipts for spy-money, which, doubtless, were properly filed in some inoffensive-appearing office in the city--one day to be transferred to Berlin! He had come for information, and here was information. One of the men who received money from Philip was a man who received a weekly wage from the Waite Motor Company.... The gang-boss of the spies who were working in the plant. Potter recognized the name, and, as the man turned, recognized the man.... And Philip--von Essen's chauffeur, the man who had struck him down in Cantor's behalf that day out in Bloomfield Hills! Philip, apparently paymaster-in-chief for the master spy! It was getting close to headquarters.... Did the trail lead from Philip to Cantor? Could it be followed? He reflected. Here was no time for headlong action. Now was the moment to exercise guile and restraint. To frighten the subordinate would be to warn the superior. To catch the subordinates would be nothing but a temporary setback; to use the subordinates as stepping-stones to reach the chief would be an achievement. He remained motionless, waiting. Presently the men stepped out of the garage and stealthily made their way to the street. Potter did not follow. For ten minutes, twenty minutes, he waited, then feeling it would be safe to move, he stepped from his place and crept inch by inch away from the garage. Presently he got to his feet and, dodging from shrub to shrub, reached the street and hastened toward home. It had been a night of nights; a night of bitter failure, of gnawing suffering; a night of unexpected success. The success did not uplift him. It was there. The facts were in his possession to be made what use of was possible.... He did not continue to consider them for long. The personal grief was stronger than the public benefit. It meant more to him that Hildegarde von Essen was wholly contemptible than that he had it within his power to thwart the plot calculated to destroy the thing his country needed most. In that hour aeroplanes were less to him than one girl.... CHAPTER XXV