The door opened to admit two brisk, prosperous-looking gentlemen.

“I fear we are late,” said the foremost. “It was unavoidable, I assure you.”

“It is never too late,” said Zimmerlein, advancing to shake hands with the new-comers. Then, while they were laying aside their overcoats, he stepped swiftly to the door of the drafting-room and called out: “Thorsensel! Come here, please. And you also, Martin.”

One of the men in the outer room, laid down the instrument with which he was working over a huge blue-print; with a sigh of resignation, he removed his green eye-shield, smoothed out his wrinkled alpaca coat, and came slowly, diffidently into the private office. He was a middle-aged, stoop-shouldered, sunken-faced man, with a drooping moustache that lacked not only in pride but in colour as well. The ends were gnawed and scraggly, and there were cigarette stains along the uneven edges. Otherwise, this sickly adornment was straw-coloured. Thick spectacles enlarged his almost expressionless blue eyes; as one looked straight into them, the eyeballs seemed to be twice the normal size.

This man was John Thorsensel, civil engineer, American—born of Norwegian parentage, graduate of one of the greatest engineering universities in the country. You would go many a league before encountering a more unimposing, commonplace person,—and yet here was the most astute secret servant in the German Kaiser's vast establishment. Not Zimmerlein, nor Riaz, nor any of the important-looking individuals who skulked behind respectable names, not one of them was the head and heart of the sinister, far-reaching octopus that spread its slimy influence across the United States of America. John Thorsensel, an insignificant toiler, was the master-mind, the arch-conspirator. It was his hand that rested on the key, his thought that covered everything, his infernal ingenuity that confounded the shrewdest minds on this side of the Atlantic. The last man in the world to be suspected,—such was John Thorsensel, bad angel.

Martin, the other man called to the conference, was a brisk young fellow who left a rolltop desk in the corner of the drafting-room and presented himself with stenographer's note-book and pencil. It is worthy of mention that this book already contained the stenographic notes of the preliminary verbal discussion between the three principals to a transaction involving the sale of great mining properties in South America. Everything was perfectly prepared, even to the abrupt termination of the conference that would come naturally in case agents of the government took it into their heads to appear. Martin's notes, jotted down weeks beforehand, broke off in the most natural way. There is no telling how many times he had sat with the note-book on his knee in just such a conference as this, without adding a single word to what already appeared on the pages. It is safe to say, however, that the notes were never transcribed.

It would have been impossible to find in the offices of Paul Zimmerlein a single incriminating line, or article, or suggestion of either,—for the simple reason that no such thing existed. Nothing ever appeared in tangible form. Visitors were always welcome.

Once and once only had the slightest symptom of a creak appeared in the well-ordered machine. One man was suspected,—merely suspected. There was no actual evidence against him in the hands of the conspirators, but the fact that a possibility existed was enough for them. He was an ordinary window-washer who came twice a month to the office,—not oftener,—in his regular round of the building. Always it was the same man who washed Zimmerlein's windows, and always a few words passed between him and the engineer,—words that no one else heard. One day the device to which his safety belt was attached gave way and he fell fourteen storeys to the roof of the building below. He was to be trusted after that.

The six men gathered in the office of Mr. Paul Zimmerlein formed a combination of intelligence, wealth, energy and evil sufficient to satisfy even the most exacting of masters. Here were the shrewdest, the safest, the soundest agents of the cruelest system in all the world. No small, half-hearted undertaking in frightfulness ever grew out of their deliberations; no sporadic, clumsy botch in the shape of needless violence; no crazy, fore-doomed project; no mistakes. They were the big men,—the men who did the big things.

Out of every nook and cranny in the land oozed constant and reliable reports from the most trustworthy sources, from agents of both sexes; sly, secret, mysterious forces supplied them with facts that no man was supposed to know; the magic of the Far East was surpassed by these wizards who came not out of Egypt but from commonplace, unromantic circles in the Occident.