The minutes passed as the policeman and I watched our prisoner in the cellar, by the tube.  I looked anxiously at my watch.

“Craig!” I shouted at last, unable to control my fears for him.

No answer.  To go down after him seemed out of the question.

By this time, Craig had come to a small open chamber into which the sewer widened.  On the wall he found another series of iron rungs up which he climbed.  The gas was terrible.

As he neared the top of the ladder, he came to a shelf-like aperture in the sewer chamber, and gazed about.  It was horribly dark.  He reached out and felt a piece of cloth.  Anxiously he pulled on it.  Then he reached further into the darkness.

There was Elaine, unconscious, apparently dead.

He shook her, endeavoring to wake her up.  But it was no use.

In desperation Craig carried her down the ladder.

With our prisoner, we could only look helplessly around.  Again and again I looked at my watch as the minutes lengthened.  Suppose the oxygen gave out?

“By George, I’m going down after him,” I cried in desperation.

“Don’t do it,” advised the policeman.  “You’ll never get out.”

One whiff of the horrible gas told me that he was right.  I should not have been able to go fifty feet in it.  I looked at him in despair.  It was impossible.

“Listen,” said the policeman, straining his ears.

There was indeed a faint noise from the black depths below us.  A rope alongside the rough ladder began to move, as though someone was pulling it taut.  We gazed down.

“Craig!  Craig!” I called.  “Is that you?”

No answer.  But the rope still moved.  Perhaps the helmet made it impossible for him to hear.

He had struggled back in the swirling current almost exhausted by his helpless burden.  Holding Elaine’s head above the surface of the water and pulling on the rope to attract my attention, for he could neither hear nor shout, he had taken a turn of the rope about Elaine.  I tried pulling on it.  There was something heavy on the other end and I kept on pulling.

At last I could make out Kennedy dimly mounting the ladder.  The weight was the unconscious body of Elaine which he steadied as he mounted.  I tugged harder and he slowly came up.

Together, at last, the policeman and I reached down and pulled them out.

We placed Elaine on the cellar floor, as comfortably as was possible, and the policeman began his first-aid motions for resuscitation.

“No—­no,” cried Kennedy, “Not here—­take her up where the air is fresher.”

With his revolver still drawn to overawe the prisoner, the policeman forced him to aid us in carrying her up the rickety flight of cellar steps.  Kennedy followed quickly, unscrewing the oxygen helmet as he went.

In the deserted living room we deposited our senseless burden, while Kennedy, the helmet off now, bent over her.