The second night of the fog stole softly around the ship. As the chill and dripping air changed from pearly gray to starless gloom, the hoarse and frequent whistle seemed to be appealing for guidance on this sightless sea. Bridge, deck, and engine room were unceasingly vigilant. Their first warning of deadly peril came when a blast from the whistle was hurled back in a volley of echoes from somewhere dead ahead. Captain Thrasher leaped to the engine-room indicator and signalled full speed astern, with both screws.