ON that seventh day when Bentham finally decided to abandon the boring, the navvy, in whom I had detected such a resemblance to Dornton, disappeared. The workers were numbered every four hours when they changed and changed about, and the missing one being in what Bentham called "the starboard watch," there were at least four hours in which his movements had to be inquired into. At first the theory was that he had in some way managed to elude the sentries, and jump down the sewer; but when it was discovered that he had answered his number quite an hour after the sewer had been hermetically sealed, the matter began to assume a mysterious aspect. Every nook and cranny was searched and searched again; no trace of the missing one was found— he had absolutely disappeared. How and why we did not ask— the answer came all too readily, as we cast trembling eyes towards the grey stone barrier that stood between us and Mirzarbeau's annihilator.

So far as possible Bentham suppressed the news, and kept all hands busy pulling back the boring-engine, and generally making preparations to quit; but ill news travels fast, and there was a feverish uneasiness visible in the work.

In this labour I took no part; some while before, when I was still in the full heat of annoyance at my forcible detention in this filthy hole, Bentham had asked whether I would care to lend a hand at the work in order to while away the time, and I had emphatically refused. Now that I would have given a deal to be employed, I was not asked; and even when I volunteered, my offer was curtly refused. So I prowled aimlessly about, compelled to keep up by the grey barrier, since all the rest of the place was full of machinery and explosives, and the men who moved them.

As I wandered thus, I tried my hardest to believe that Dornton had not lied when he told me of Mirzarbeau's having used up all his devastating power, and to some extent I succeeded.

I sought to interest myself in trifles, closely examining the grey stone wall that had so signally defeated the boring-engine. I had seen this cement-like substance before, but had never had the inclination to closely examine it. Now, I noted that it seemed to be made up of large prisms which gave it the appearance of a geometrical pattern. These patterns I followed with my eye; after the fashion of a sick man tracing imaginary patterns upon a wall-paper.

In this way I found myself following one line that went up, across, and down, then across and up again once more. I followed it round several times before its full significance burst upon me.

When it did I turned and bolted down the tunnel like a maniac. For I suddenly realized that the thing was a door; and it needed no imagination to guess what that might mean, or to what use it might at any moment be put.

Racing down the dimly-lit tunnel I plunged wildly into Bentham and some of his men, nearly getting bayoneted as a fugitive before they recognized me. Even when they did, and I had gasped out a warning, the lieutenant took it very stoically.

"You've fancied it," said he, "even Mirzarbeau can't be supposed to fit his place with doors twenty feet underground. Come and point it out."

I would have refused; but since my being conveyed thither by force was sure to be the answer to that, I obeyed with trembling feet, going up the tunnel with him while the men remained behind.

Some ten or twelve yards from the thing that I had noticed the tunnel curved slightly, so that we could not see the marks till, almost close upon the place. But when we turned the corner all doubt about the door was set at rest, for now there was a black gap in the wall where the marks had been, and standing in front of it, fat, smiling, sleek as ever, was Mirzarbeau himself!