special line of business? How are you going to get at this man Penfield, I mean?”

“Ever hear of the Miami outfit?” asked the other.

“That cut in and hit the Montreal pool-rooms for eighty thousand?—well, I guess I have, a little!”

Durkin glanced at his companion, in wonder. Then the truth seemed to dawn on him, in one illuminating, almost bewildering, flash.

“You—you’re not MacNutt?” he cried, reading his answer even while he asked the question. Half a year before, the Postal-Union offices had been full of talk of the Miami outfit and MacNutt, buzzing with meagre news of the cool insolence and audacity of Miami’s lightning-slingers, who, when they saw they had worked their game to a finish, cut in with their: “We’ve got your dough, now you can go to——” as they made for cover and ultimate liberty ten minutes before their hillside cave was raided, and nothing more than a packing-case, holding three dozen Brumley dry batteries, a bunch of “KK,” and a couple of Crosby long-distance telephones, was found.

Durkin looked at the other man once more, almost admiringly, indeterminately tempted, swayed against his will, in some way, by the splendor of a vast and unknown hazard. He found a not altogether miserable consolation, too, in the thought that this possible second dip into illegitimate activities would be a movement not directed against organized society, but against one already an enemy of that society. Yet even this draught of sophistry left its after-taste of disgust.

“You’re pretty confidential,” he said, slowly, looking the other up and down. “What’s to stop me going to one of Doogan’s men and squealing on the whole gang of you?”

MacNutt smiled, gently and placidly, and stroked his short beard, touched here and there with gray. “And what good would all that do you?” he asked.

“You are a cool specimen!” ejaculated the other.

“Oh, I guess I know men; and I sized you up, first thing, in the court-room. You’re the sort o’ man I want. You’re not a funker, and you’ve got brains, and—well, if you don’t come out of this quite a few thousand to the good, it’s all your own fault!”

Durkin whistled softly. Then he looked meditatively out at the flashing motor-cars as they threaded their way up the crowded avenue.

“Well, I guess I’m game enough,” he said, hesitatingly, still trying to sweep from his brain the clouding mental cobweb that it was all nothing more than a vivid nightmare.

“I guess I’m your man,” he repeated, as they turned off the Avenue, and drew up in front of a house of staid and respectable brownstone facing, like so many of the other private houses of New York’s upper Forties. In fact, the long line of brownstone edifices before him seemed so alike that one gigantic hand, he thought, might have carved the whole block from a single slab of that dull and lifeless-looking brownstone rock.

Then, following MacNutt, he jumped out and went quickly up the broad stone steps.

“So you’re with us, all right?” the older man asked, as his finger played oddly on the electric button beside the door. Durkin looked at the blank glass and panels that seemed to bar in so much mystery, and his last quaver of indecision died away. Yet even then he had a sense of standing upon some Vesuvian-like lava-crust, beneath which smouldered unseen volcanic fires and uncounted volcanic dangers.

“Yes, I’m with you, anyway,” he asserted, stoutly. “I’m with you, to the finish!”

It was a full minute before the door swung open; and the unlooked-for wait in some way keyed the younger man’s curiosity up to the snapping point. As it finally opened, slowly, he had the startled vision of a young woman, dressed in sober black, looking half timidly out at them, with her hand still on the knob. As he noticed the wealth of her waving chestnut hair, and the poise of the head, and the quiet calmness of the eyes, that appeared almost a violet-blue in contrast to the soft pallor of her face, Durkin felt that they had made a mistake in the house number. But, seeing MacNutt step quickly inside, he himself awkwardly took off his hat. Under the spell of her quiet, almost pensive smile, he decided that she could be little more than a mere girl, until he noticed the womanly fullness of her breast and hips and what seemed a languid weariness about the eyes themselves. He also noted, and in this he felt a touch of sharp resentment, the sudden telepathic glance that passed between MacNutt and the woman; a questioning flash on her part, an answering flash on the other’s. Then she turned to Durkin, with her quiet, carelessly winning smile, and held out her hand,—and his heart thumped and pounded more drunkenly than it had done with all MacNutt’s bootlegger’s gin. Then he heard MacNutt speaking, quietly and evenly, as though talking of mere things of the moment.

“This is Mr. Jim Durkin; Durkin, this is Miss Frances Candler. You two’re going to have a lot o’ trouble together, so I guess you’d better get acquainted right here—might as well make it Frank and Jim, you two, for you’re going to see a mighty good deal of one another!”

“All right, Jim,” said the woman, girlishly, in a mellow, English contralto voice. Then she laughed a little, and Durkin noticed the whiteness of her fine, strong incisors, and straightway forgot them again, in the delicious possibility that he might hear that soft laughter often, and under varied circumstances. Then he flushed hot and cold, as he felt her shaking hands with him once more. Strangely sobered, he stumbled over rugs and polished squares of parquetry, after them, up two flights of stairs, listening, still dazed, to MacNutt’s hurried questions and the woman’s low answers, which sounded muffled and far away to him, as though some impalpable wall separated them from him.

A man by the name of Mackenzie, Durkin gathered from what he could hear of their talk, had been probing about the underground cable galleries for half a day, and had just strung a wire on which much seemed to depend. They stopped before a heavy oak-panelled door, on which MacNutt played a six-stroked tattoo. A key turned, and the next moment a middle-aged man, thin-lipped, and with blue veins showing about his temples, thrust his head cautiously through the opening. The sweat was running from his moist and dirt-smeared face; a look of relief came over his features at the sight of the others. Durkin wondered just why he should be dressed in the peaked cap and blue suit of a Consolidated Gas Company inspector.

The room into which they stepped had, obviously, once been a sewing-room. In one corner still stood the sewing-machine itself, in the shadow, incongruously enough, of a large safe with combination lock. Next to this stood a stout work-table, on which rested a box relay and a Bunnell sounder. Around the latter were clustered a galvanometer, a 1-2 duplex set, a condenser, and a Wheatstone bridge of the Post-Office pattern, while about the floor lay coils of copper wire, a pair of lineman’s pliers, and a number of scattered tools. Durkin’s trained eye saw that the condenser had been in use, to reduce the current from a tapped electric-light wire; while the next moment his glance fell on a complete wire-tapping outfit, snugly packed away in an innocent enough looking suit-case. Then he turned to the two men and the woman, as they bent anxiously over the littered table, where Mackenzie was once more struggling with his instrument, talking quickly and tensely as he tested and worked and listened.

“Great