the city hall clock boomed out the hour of 7.
Falteringly, plainly in a state bordering on collapse, but more afraid of turning back than of unknown dangers before her, Fraulein Mueller mounted the mansion's wide stone steps and rang the doorbell timidly.
As soon as the black dwarf had admitted her, de Grandin leaped up the area steps and hastened across the street to the big, black limousine parked before Laïla's door. For a moment he fumbled about the car's gas tank, then sped back to where I waited and riveted his gaze on the portal through which Fraulein Mueller had vanished.
We had not long to wait. Almost before the Frenchman had regained his ambush, the big door swung open and Laïla and the little Austrian girl emerged, descended the curving stairs and entered the waiting limousine. There was a buzzing, irritable hum of the self-starter, the spiteful swish of the powerful motor going into action; then, with a low, steady hum, the car glided from the curb and shot down the street with surprizing speed.
"Quick, Friend Trowbridge," de Grandin urged, seizing me by the hand and dragging me to the street, "to your car. Haste! We must follow them!"
I gazed after the fleeing motor and shook my head. "Not a chance," I declared. "They're doing better than thirty miles an hour now, and gathering speed all the time. We'd never be able to keep their trail with my little rattletrap."
"My friend," he replied, piloting me across the street and fairly shoving me into my car, "Jules de Grandin is no fool. Think you he slept away his time this afternoon? Regardez-vous!" With a dramatic gesture he pointed to the roadway before us.
I blinked my eyes in astonishment, then grinned in appreciation of his strategy. In the wake of the speeding limousine there shone a faint but unmistakable trail of luminous dots against the cement pavement. Now I understood what he had been doing at the other car's tail during the interval between Fraulein Mueller's entrance and Laïla's exit. Firmly attached to the limousine's gas tank was a small can of luminous paint, a small hole pierced in its bottom permitting its telltale contents to leak out, a drop at a time, at intervals which spattered the roadway with glowing trail-markers every thirty or forty feet.
Through the city, over country roads, up hill and down, over viaducts, across stretches of low-lying marshes, through wide, wooded areas and between long, undulating stretches of fields ripe for harvesting, the chase continued. The mileage dial on my dashboard registered forty-five, sixty, sixty-five miles before the car ahead swerved sharply from the highway, shot down a private lane, and entered the high, iron-grilled gateway of a walled estate.
"Eh bien," remarked de Grandin, "here we are, of a surety, but where is it we are?" Parking our ear behind a convenient copse of second-growth pines, we stole forward to reconnoiter the enemy's position. Our progress was barred by the tall iron gates which had been securely locked behind our quarry. Through the grillework of the barrier we could descry tall evergreens bowing and whispering with cemeterylike somberness on each side of a wide, curving driveway, and between their ranks we caught momentary glimpses of the ivy-covered walls and white porch pillars of a large Colonial-type residence.
De Grandin gave the gate-handle a tentative shake, confirming our suspicion that it was firmly secured. "It would be wiser not to attempt scaling
