the leg of the desk,
through the very walls to the huge chandelier in the library below,
where, in the ornamented brass-work, reposed a small black disk about
the size of a watch. It was the receiving-end of the dictagraph.

Suddenly the young man's face broke out into a smile and without
thinking he stopped writing what the little mechanical eavesdropper was
conveying him from below. He listened intently as he heard a silvery
laugh over the wire.

"Oh, I didn't know you were busy. I thought these flowers--Well, never
mind. I'll leave them, anyway."

It was Eva Brent, daughter of the head of the firm, who had danced in
from the conservatory like a June zephyr in December.

"My dear," Locke could hear the patent magnate welcome, "it is all
right. Stay a moment and talk to this gentleman while I go down to the
museum."

Locke listened eagerly, glancing now and then at a photograph of Eva
Brent on his own desk, while she chatted gaily with the inventor. It was
evident that Eva had not the faintest idea of the hard nature of the
business of her father.

Meanwhile, Brent himself had left the library and passed through the
portiered door into the hall. He did not turn up the grand staircase in
the center of the wide hall, but hurried, preoccupied, to a door under
the stairs that opened down to the cellar.

He started to open it to pass down. As he did so he did not hear a light
footstep on the stairs as his secretary, Zita Dane, came down. But he
did not escape her watchful eye.

"Mr. Brent," she called, "is there anything I can do?"

Brent paused. "Wait a moment for me in the library," he directed, as he
turned again to enter the cellar.

He closed the door and Zita watched him with an almost uncanny interest,
then turned to the library to join Eva and the new-comer.

Down the cellar steps Brent made his way, and across the cellar floor,
pausing at the rocky wall of the foundation of the house blasted and
hewn out of the cliff on which it towered above the river. A heavy steel
door in the rock wall barred the way.

Brent whirled the combination and shot the bolts, and the door swung
ponderously open, disclosing a rock-hewn cavern. Three walls of the
cavern were lined with shelves containing inventions of all
kinds--telegraph and telephone instruments, engine models,
railroad-signaling and safety devices, racks of bottles containing
dangerous chemicals and their antidotes--all conceivable manner of
mechanical