He was looking down upon that little circle of dark waters over which the hoary filaments of mist were drifting. He was reading its secrets--the movement of the tide, the direction of the swirling currents, the strength with which they were pushing upon the liner’s submerged keel. He was listening to the sounds in the gray fog--the whistle of the _Empress_, appealing hoarsely for guidance; the echoes with which the steep Marin County hills answered that appeal; the crashing blare of the Fort Point diaphone over to the right. These things and a strange sixth sense of locality which had come through long experience gave MacKenzie a picture. In his mind’s eye he saw beyond the limits of that little circle on the dark waters. He saw the ship and her surroundings as he would on a clear day. That mental vision portrayed the liner, now entering the neck of the funnel-shaped lane, approaching close to the inner portal of the Golden Gate. Close beside her it showed the Marin County hills, rising straight from the water; before her bows, barring the way with its rock walls, Lime Point; across the narrow channel from this--ahead and to his right--Fort Point. That was the picture. The echoes came down from the hills; the Lime Point siren roared straight ahead of him; and over there to the right the Fort Point diaphone was bellowing like a hundred fear-maddened bulls. The ship crept on. In his mind’s eye MacKenzie saw the steep, black prow approaching Lime Point--until, within a minute, he must say the word which would compel the _Empress_ to turn to the right in order to avoid the rocky promotory as she passed through the narrows. Then a strange and terrible change came. The echoes from the steep hills dwindled and died away. The roaring of the Lime Point siren grew fainter, more remote, as if the ship were being shoved off to the right. The crashing diapason from Fort Point was growing with appalling suddenness. At this same moment the color of the waters which swirled against the steel flanks of the _Empress_ deepened to a turgid brown. The ebb tide was rushing seaward. The captain halted abruptly. His tall form was erect no longer; he leaned forward, and his face was pallid as he peered into the fog toward the spot from which that diaphone’s blare emerged. In the instant, MacKenzie became rigid. He stood like a grim statue. His shaggy brows seemed to hide the eyes beneath them. Under his heavy, gray mustache his lips pressed tightly together. And he asked himself a question: Had he erred?