Stepping over to where three levers stood in the centre of the compartment the captain thrust one hard down. Instantly a portion of the floor opened. Another lever caused a corresponding part of the outer plating to slide back, revealing an observation plate of about three feet by two through the double skins of the starboard bilge-plates.
"I can see nothing," said Hythe, as he strove to peer through the glass. "It is perfectly dark."
"There ought to be sufficient light at this depth to see fairly well, but since the 'Aphrodite' is still on or nearly on the bottom of The Narrows, the hull intercepts what little light there is to penetrate the water. Now look!"
Touching a switch Captain Restronguet caused a strong search-light to shine vertically downwards. About a fathom of water lay between her keel and the floor of the sea. She was slowly moving under the influence of the young flood tide. The bed was shelving steeply from one hundred and twenty feet to less than ninety. Hythe could see the seaweed waving in the current and the fash, mostly of the flat-fish tribe, darting rapidly towards the dazzling light.
"What's that?" he asked, as two objects, resembling barnacle-covered pipes passed slowly across the field of light.
"Telephone cables between the Victualling Yard and Mount Edgcumbe," replied his companion. "If I felt inclined, what is to prevent me from sending out a man and tapping those wires? All submarine cables are entirely at my mercy. If I wished I could create a greater panic than the Stock Exchange, the Bourse, or Wall Street ever yet experienced. But I must switch off the light and close the panels now. I am wanted in the conning-tower."
As the sub followed his companion he could not help noticing the freshness of the atmosphere. Compared with the nauseating reek of the submarines he had served in the interior of the "Aphrodite" was as wholesome as could be. There was, moreover, a sting in the atmosphere that recalled the health-giving breezes of the Scottish moors.
"All right, Mylor, you carry on," exclaimed the captain to the helmsman in the conning-tower. "Starboard your helm a bit--go!"
Forty feet beneath the surface the submarine swung round the sharp band formed by the high ground of Cremyll and Mount Edgcumbe. Close to the heavy mooring-chains to the south of the Rubble Bank she glided, till her course, almost due north, lay right up the land-locked Hamoaze.
"Why, we're going up the River Tamar!" exclaimed Hythe, glancing at the compass. His knowledge of the intricacies of Plymouth Harbour and the Hamoaze, and the compass course told him that, for nothing was to be seen through the conning-tower scuttles save an expanse of pale green water.