Another elevator was descending. It stopped on Potter's signal, and he stepped in. "To the ground floor--quick. Make no stops. Drop her." The startled elevator conductor obeyed, flung open the door as he arrived level with the street, and Potter rushed out. He reached the sidewalk just in time to see Philip in an automobile, half a block away. Potter stepped quickly into his own machine and followed. He had no other thought but to overtake Philip. Just what he should do when he overtook him was not a consideration for that moment. Headlong as usual, he counted no costs and let each second care for that second's concerns. That he had no authority to apprehend Philip did not trouble him in the least. He believed he had the physical ability, and that was all he required. Philip turned east at the Campus and traversed Cadillac Square to the County building and the intersection of Congress Street. Out this frayed and shabby thoroughfare he continued, not with the speed of one who fancies himself pursued, but as one travels who is upon important errand. Potter maintained a position a hundred feet behind and waited for Philip to stop. Philip did not stop for a dozen blocks. Then he drew up at the curb before a dingy frame structure housing one of those hand-to-mouth saloons which seem to abound in Detroit, saloons which sell enormous glasses of beer for a nickel, and find difficulty to make both ends meet, to provide food for the family and funds to pay the considerable government license. Into this place Philip hastened. Potter was at his heels, stepping into a murky room reeking with the odor of stale beer, villainous tobacco, and even more distressing aromas of cookery not guiltless of the taint of garlic. Three men occupied the barroom, the bartender, sprawling over his greasy bar, a stout man dozing in a corner, and Philip. Upon Potter's entrance Philip turned and faced the door, and Potter saw surprised recognition in his eyes. "Well, Philip," said Potter, "I've got you." "You have, eh?" said Philip. "What do you mean--got me?" "When your friend in Cantor's office pushed the button," said Potter, "I tagged along after you." He continued to advance. "That's far enough," Philip said, crouching. "You tagged along, eh? Well, just tag out of that door again." "Better come along without a row." "If you want to keep your health," said Philip, crouching, "you'll beat it and leave me alone." Potter turned to the bartender, who no longer sprawled, but eyed him intently. "This man is a German spy--trying to escape and warn other spies," Potter said. "No!" said the bartender, with profound astonishment. "You don't tell me! Him? Why, I know him! He hain't no spy--he's a chauffeur.... You hain't no spy, be you, Phil?" "Certainly not. This guy is nutty.... Look here, Mr. Waite, I don't want you should get hurt. Take your foot in your hand." "Are you coming with me?" Potter asked, sharply.