The submarine was now running at a little less than eight knots and at thirty-five feet below the surface. The electrically operated periscope with its flexible attachments was in operation, and by looking at the object-board the sub could discern what appeared to be a range of hills, above which a remarkably-shaped peak towered to a considerable height. Close to the edge of the cliffs could be seen a circular lighthouse and the keeper’s house, both painted white. Some little distance from the cape two forbidding looking rocks reared their gaunt black heads above the sea, while between these rocks and the shore was a tumbling mass of white foam. "Is that the cape? Where, then, is the bay?" asked Hythe. "It is hardly recognizable from the distance. There it lies--away to the east’ard. A point to starboard, quartermaster--gently does it--so." Slowly and steadily the "Aphrodite" approached the desired anchorage. Through the starboard observation scuttle the sub saw vicious-looking rocks more than once, rising boldly from the bottom of the sea at less than twenty yards off. Between them were cavernous depths that could only be compared to an American canyon suddenly submerged in a tremendous flood. While the quartermaster kept the "Aphrodite" on her course Captain Restronguet directed all his attention to the submarine cliffs. Hythe could hear him counting as the dangerous rocks appeared to slip by. "Hard a port." Round swung the "Aphrodite" till her bows pointed straight for a narrow gap in the rocks. The sub stood aghast. Surely it was courting disaster to plunge into a submarine defile, so dark and so narrow that it seemed an impossibility for her to pass without touching the jagged pinnacles on either hand? The gauge now showed a depth of fifty-five feet. At a sign from the captain, Kenwyn touched a switch and instantly two parallel beams of brilliant light flashed from the sides of the conning-tower. As far as the beams penetrated nothing but water could be seen, but in the reflected light on either hand the ghost-like rocks flitted past in a seemingly endless procession. The "Aphrodite" was threading an intricate passage between the dangerous shoals of Machichaco Bay. Suddenly a weed-covered crag, looking like a pillar of glistening silver, came within the zone of the port search-light. A slight touch at the helm and the "Aphrodite" swung round, clearing the danger with comparative ease. On and on she went, literally crawling and smelling her way through that forbidding channel. Presently Captain Restronguet touched Hythe upon the shoulder. "Look!" said he, at the same time switching on a supplementary search-light that, instead of playing in a fore and aft direction, threw its beam at right angles to the submarine’s course. For less than ten seconds the captain kept the light switched on, but in that short interval the sub saw something that made the blood run cold in his veins.