Sprague spread his arms and crushed the other three back into the shadows. “It isn’t the watchman this time—be ready!” he whispered; and as he said it the figure of a man appeared coming down the littered roadway from the blacksmith shop.
Though he walked in darkness there was no incertitude about the man’s movements. Turning abruptly out of the material-road he went straight to the foundry shed. A moment later a beam of white light played steadily upon the acid carboys, a sheltered beam which seemed to come from a tiny electric search-light. Plainly they saw a pair of hands place a large bottle on the ground, remove the stopper, and fix a tin funnel in the neck. Then one of the carboys was tilted, presumably by the same pair of hands, though the hands were invisible now, and a thin stream of the yellow acid gurgled through the funnel.
When the bottle was filled the carboy slowly righted itself; the hands came in view again to remove the funnel and to replace the stopper; and then the search-light went out with the faint snap of an electric switch. Almost at the same instant the watchers saw the figure of the man fading away into the inner and darker blackness of the foundry.
“We’ve got to follow him, Tarbell,” said Sprague, hurriedly; “and we lose out if he discovers us. Can you pilot us?”
“I can,” asserted Maxwell, and under the superintendent’s lead the shadow race was begun.
Happily, there was a noisy diversion to make the secret pursuit feasible. The train-making clamor had come down from the western yards, and for the moment the yard crew was working on the freight-house tracks opposite the shops. Under cover of the out-door clamor the four pursuers were able to close up on the bottle-carrier until they were treading almost in his footsteps. The route led through the foundry floor to the machine shop. On the erecting pits were two locomotives, apparently ready to be hauled out and put into service after their period of back-shop repairs.
Into the cab of one of the engines the bottle-bearer climbed, first placing his burden carefully in the gangway. A little later they heard him climbing over the coal in the tender, heard him remove the cover of the water manhole, and heard the glug-glug of liquid issuing from a bottle-neck.
Sprague silently drew a small square object from his pocket, the little flat black box he had caught up as he was leaving his office in the Kinzie Building. Then he whispered to Tarbell: “Cover him, Archer, and don’t hesitate to shoot if you need to: ready!” At the word there was a blinding burst of illumination and the report of a flash-light cartridge, followed instantly by the crash of the breaking bottle, silence, and black darkness. Then Sprague’s mellow voice boomed into the stillness.
“Come down, Mr. Bascom. We’ve got your picture, and a man who doesn’t often miss what he shoots at is covering you with his gun.”
It was a grim little group of five which gathered in the master mechanic’s room in the office wing of the machine shop a few minutes after the flash-light photograph had been taken in the erecting shop. Bascom’s ruddy flush was gone when he sat down heavily in his desk chair; but his natty brown crush hat was pushed back, and the gleam in his small, lynx-like eyes was not of fear.