If he had--if in the painting of that mental picture he had been mistaken--by a quarter of a mile in distance, by two minutes in time--this seven-knot ebb tide would be carrying the liner far over to her right. She would be steaming toward Fort Point. It had occurred once. Another ship, laden, like this one, with hundreds of men and women, had been swung off her course in a fog by the ebb tide, lusty with freshet waters, and driven on those rocks. The bones of that ship lay somewhere on the bottom mingled with the skeletons of her passengers. Two minutes! And that narrow interval of time depended to a hair upon the superiority of the _Empress’_ throbbing propellers over the opposition of the waters. What man could measure the results of that struggle down there under the surface? Or tell to exactness what might the currents were putting forth to-day? The hillsides gave no echo now. The Lime Point siren died away entirely. The Fort Point diaphone crashed louder. The minute at whose expiration MacKenzie had intended to speak the word by which the liner would turn reached its final second. He put that question by. He had made his calculation in the beginning. Now he spoke. The ship turned. Her bow swung toward Fort Point; she steamed straight into that blaring warning as if she were defying it. Her captain sprang toward MacKenzie; his right hand was upraised in a gesture of terrible protest; he was sweating; great beads of water stood out on his forehead. “Man!” he shouted hoarsely. “The current! Can’t you see?” He pointed frantically into the din of the diaphone as though it were a visible thing. “Can’t you hear? You’re piling her up on Fort Point!” MacKenzie stood rigid. His head was thrust forward as if he were straining to listen for some other sound than that reverberating thunder which was overwhelming the entire ship; as if in this moment he were hoping to catch some shred of noise from the Lime Point siren in the place where he had pictured it. But there was no answer from that quarter. The _Empress_ kept on turning. Over her bows now, nearer, louder, terrible in volume and intensity, Fort Point’s warning came. The captain leaped in front of MacKenzie. His hand flew out toward the marine telegraph. “Stop her!” His voice was heavy with horror. MacKenzie seized the captain’s arm, and his fingers were like iron as he pulled it back from the handle of the telegraph. There was a sharp struggle; the captain tore away from him and whirled toward the man at the wheel. His lips parted; but even as he uttered the first word of that order to alter her course, MacKenzie drowned that order with his own deep-voiced command: “Keep her headed as she is now!” Then, as the ship moved on into the grayness, while the blare from Fort Point welled straight above her lofty prow, the captain groaned and clutched the rail instinctively, as though to save himself against the impact of the collision with those rocks.