After we had been driving for something like five minutes, a most curious thing happened. I was trying to make out an object in the street through which we were passing, when suddenly I found myself in total darkness. Putting my hand up to the right-hand window to see what had occasioned it, I found that a sheet of iron had interposed itself between me and the glass. The same thing had happened in front and on the opposite side, though how it had been arranged, I could not for the life of me discover. Then I tried the doors, but the handles refused to turn. I felt that I was trapped indeed, and to make matters worse, a villainous smell of gas was fast taking possession of the carriage. I shouted for assistance with all the strength of my lungs, but no help came. I tried to force the panels of the carriage, but it was a useless endeavour. Still the sickening smell of gas increased, until I felt that, unless I could get into the fresh air without delay, I should be suffocated--as a matter of fact my senses were already leaving me. Was this how Woller and Castellan had died? I asked myself, for in my own heart I felt that my last hour had come. Scarcely conscious of what I was doing, I believe I stood up and struggled with the door, but with as little success as before. Then I fell back upon the cushions and became oblivious to everything. How long I remained in this condition I cannot say; I only know that my next waking thought was the realisation of a spasm of acute pain. It was as if every muscle of my body were being drawn by red-hot pincers. My brain whirred as though to the rattle of a thousand pieces of machinery, while an indescribable nausea held me in its grip. I could not have lifted my head, or have opened my eyes, had my life depended upon my doing so. For what seemed an interminable time, I lay like this, totally unconscious of my surroundings, and, indeed, of everything else save my agony. After a time, however, my senses began to return to me, and I was able to reduce my thoughts to something like order. At first I had no recollection of what had transpired since I had left home, but little by little it all came back to me. I recalled the letter I had received from Rotherhithe, and the haste with which I had complied with the summons it contained. I remembered the drive through the lamp-lit streets, the sudden darkness that had descended upon me, the overpowering smell of gas, and the sensation, which I could compare to nothing, save that of approaching death, which I had experienced when I fell back upon the street.