When it came close to closing time he helped clear away used trays and other chemical apparatus, washing-up. He gathered up all films and got ready for the next day’s work. The developed and printed film he left on the drying drums, not caring to stay long in the dark-room.
When, close to the office at all times, he was certain that the staff was absolutely out of the building, he began a careful and thorough, but hurried series of operations.
His decision to stay there all night, discussed with Grover, had finally been agreed to by his older cousin.
At home, there was no way to avert the trick used before. The fuse box could not be guarded unless they hired a Falcon patrolman.
That the laboratory was more impregnable had been proved the night before by the effort used to enter. The fire, set off probably by a pole carrying a light, inserted from above the telescope, had been assurance that even the skylight was considered too risky by whoever had wanted to enter. That one had set the fire, hoping that firemen would have broken in, giving him—not her unless the stenographer was suspectable—a chance to run in with them.
What they could want (or what he could want), Roger did not seem able to decide. Not the laboratory’s secrets. When the false gem had been sought in the safe, nothing else had been disturbed.
Roger, determined to stay all night in the laboratory, made his preparations with thoroughness and care in spite of his speed.
The old microphones set at doors, windows and other probable entrances, he tested. The cameras he took out of circuit. They would not need to record, because no one must get in to be snapped.
From the upper room he resurrected the old shadow-box with its panel of lights, connecting them into circuits so that the least disturbance by any microphone, even a vibration of its sensitive diaphragm by slight sounds, would cut a relay and light the right lamp.
The connections of the magnetic plates he traced, to be sure no one had cut a cable. Where they all came together at the transformer Roger transferred the connection from the 180-volt step-up to the next higher output. Anyone touching any plate must receive a 300-volt charge. He would not risk anyone getting away, granting that such a one got past the bolts he wired fast, as he did with window catches.