The last minute vibration ebbed out of the transmitter’s tingling diaphragm; but still neither the listening man nor woman moved. They waited, tense, expectant, tossed between doubt and hope, knowing only too well that the questioning tinkle of a little polished, nickel bell would sound the signal of their absolute and irreparable defeat.

Second by second, a minute dragged itself away. Then another, and another, and still no call came from Ottenheimer’s office, for Central. The woman moved a little restlessly. The man sighed deeply. Then he slowly put down the receiver, and mopped his moist face and forehead.

“I think he’s safe,” half-whispered Durkin, with his eyes still on the transmitter.

“He may suspect any moment though—when he’s had time to think it over, especially.”

“I rather doubt it. Our voices were nothing but broken squeaks. But if he does ring up Central, we’ll have to risk it and jump in and claim a wire’s crossed somewhere.”

Then he repeated the strange formula: “To the right three times, to seventy-four—back thirty—on eighty-two—back one hundred and eight—and on seven. Can you get it down, Frank?”

She nodded, as she wrote it in pencil, on a slip of paper. This he placed in his waistcoat pocket, and mopped his face once more, laughing—perhaps a little hysterically, as he watched the ’phone and felt the passing minutes drip relievingly, like the softest of balm, on his strained nerves.

“And now what?” asked Frances, sharing his relief, as he went to the window, and breathed the fresh air that blew in through the low-ceilinged little studio.

“Now,” said Durkin, jubilantly, “now we begin our real work!” He opened his suit-case and handed her a heavy, cylindrical, steel implement. Into one end of this odd-looking tool he slipped and clamped a slender, polished little shaft of grooved steel.

“That’s what nearly lost me everything,” he continued, carefully unpacking, as he spoke, a condenser, a tangent galvanometer, a pair of lineman’s-gloves, a Warner pocket battery-gauge, a pair of electrician’s scissors and pliers, two or three coils of wire, a half-a-dozen pony glass insulators, and a handful or two of smaller tools.