He shook his head. "Sea Queen out of Hamburg," he said, "and a pleasure yacht from the look of her. But what she does here beats me." The caisson closed, and the steam-yacht warped up slowly to the pier. There was little or no noise on her, only a voice raised occasionally in an authoritative command, and the rattling of chains that paid out through the donkey-engine. Idly I moved to the stone quay when the gangway was let down, but only one man descended. The passengers, if there had been any, had long since reached town from Tilbury, saving themselves that uninteresting trudge up the winding river-lane. I moved on to where a steamer was being loaded under the electric lights, and watched the same for some time with interest; then, taking out my watch, I examined it, and came to the conclusion that if I was to see any patients that evening at all I must at once get back to my unpalatable rooms. I began to go along the pier, and passed into the shadow of the Sea Queen, now sunk in quiet, and drab and dark. As I went, a port-hole in the stern almost on the level of my eyes gleamed like a moon, and of a sudden there was an outbreak of angry voices, one threatening volubly and the other deeper and slower, but equally hostile. It was not that the altercation was anything astonishing in human life, but I think it was the instantaneous flash of that light and those voices in a dead ship that pulled me up. I stared into the port-hole, and as I did so the face of a man passed across it 'twixt the light and me; it passed and vanished; and I walked on. As I turned to go down to the gates I was aware of the approaching fog. I had seen it scores of times in that abominable low-lying part of the town, and I knew the symptoms. There was a faint smell in the air, an odour that bit the nostrils, carrying the reek of that changeless wilderness of factories and houses. The opaque grey sky lost its greyness and was struck to a lurid yellow. Banks of high fog rolled up the east and moved menacingly, almost imperceptibly, upon the town. For a moment there were dim shadows of the wharves and the riverside houses, with a church tower dimmer still behind them, and then the billows of the fog descended and swallowed up all. I moved now in a blackness, but bore to the right, in which direction I knew were the dock sheds and safety. I seemed to have been feeling my way for a long time—quite ten minutes—and yet I did not come upon anything. I began to be seized with the fear of a blind man who is helpless in vacancy. Had I left the basin in my rear, or had I somehow wandered back