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 pa.s.sed slowly across the field of light.

"Telephone cables between the Victualling Yard and Mount Edgc.u.mbe,"

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 Edgc.u.mbe. 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 compa.s.s. His knowledge of the intricacies of Plymouth Harbour and the Hamoaze, and the compa.s.s course told him that, for nothing was to be seen through the conning-tower scuttles save an expanse of pale green water.

"Yes, that is so. I am just running up to Saltash in order to pick up a man returning from leave," replied Captain Restronguet with a laugh. He spoke as casually as if he were the c.o.xswain of a British battleship's liberty-boat. "We are now pa.s.sing the South Yard of Devonport Dockyard.

But excuse me, I have something to attend to in the after conning-tower.

You won't mind remaining here, I trust? Keep her as she is, Mylor; I am going to reduce speed to five knots or even less."

Hythe sat down on a folding seat fixed below the port scuttle, whence he could see either ahead or on his left. The helmsman's head and shoulders obstructed the view to starboard.

It was fascinating work watching the sea swirl past, and noting the changes as the "Aphrodite" pa.s.sed through patches of various coloured water, for the tide was beginning to stir up the dark brown sediment brought down from the Devonian Hills by the swift-running Tamar, and the result was a constant kaleidoscope. But after a while, finding that nothing else was visible, the sub transferred his attention to the interior of the conning-tower.

Presently a bell gave forth a warning note and the helmsman promptly touched a lever. The depth according to the gauge diminished to less than thirty-five feet.

"Is that an automatic sounding machine?" asked Hythe.

Mylor, still keeping his eyes fixed in front of him, shut his lips tightly, and Hythe, thinking that he had not caught what had been said, repeated the question.

"Cannot say, sir," said the helmsman decidedly. "It's against orders.

For any information ask the cap'n."

"That's a staggerer," thought the sub. "One thing about it the fellow's true to his master."

Meanwhile Captain Restronguet had retired to his cabin, where he drafted a communication to the Commander-in Chief of the Devonport Command.

This done, he ascended to the after conning-tower where two seamen were on duty.

"Ship the periscope, Carclew. Directly you sight any small Government craft bearing down this way let me know. And Gwennap, get this letter ready for delivery."

The periscope consisted of a double-wedge shaped instrument connected to the top of the after conning-tower by means of a flexible armoured insulated wire. Carclew, by switching off the current from an electro-magnet, allowed the float to rise to the surface, where, owing to the comparatively slow rate of the submarine, it was towed without being dragged under. As soon as this was done another switch was manipulated, and instantly a reproduction of the surrounding objects was faithfully projected by an advanced form of telephotography upon a dull white board fixed to the wall of the conning-tower.

"There's a black pinnace with a yellow awning coming down stream, sir,"

announced Carclew. "She's got the letters M.P. on her bows."

"Police launch evidently," said Captain Restronguet. "Now Gwennap, stand by. Are we right under her course, Carclew?"

The man Gwennap had meanwhile placed the doc.u.ment in an oiled covering which in turn he lashed to a globular white and green buoy. This he placed in an ejector, made on the principle of a submerged torpedo tube.

"All ready, sir," he announced.

Captain Restronguet held up his hand, and receiving an affirmative gesture from the seaman at the periscope-board, nodded his head. There was a slight, almost inaudible hiss and the buoy with the message attached, was ejected out of the conning-tower, rising to the surface within fifty yards of the on-coming launch.

"They've picked it up, sir," declared Carclew, after half a minute had elapsed.

"That's well," murmured the captain, as he descended the conning-tower ladder. "I wonder if the reply will be in a similar strain to the one I received five years ago. Ah! I wonder."

And with a grave smile on his resolute features Captain Restronguet returned to his cabin.

"Send Mr. Hythe to me," he ordered, when a seaman appeared in answer to his summons. "And tell the diving-party detailed for duty to have the boat ready for launching; warn Polglaze and Lancarrow to stand by at eleven to-night."

"Now, Mr. Hythe," said Captain Restronguet, when the sub was shown into the cabin, "I may as well tell you that I have reported your presence and that of the able seaman to the Commander-in-Chief, and doubtless I shall have a reply before noon to-morrow. If you would like to see our periscope in working order now is a good opportunity. We are travelling dead slow, and there is plenty to be seen here--more so than at sea."

"It is a picture," exclaimed the sub enthusiastically, as he gazed upon the electrically-depicted panorama. "The whole horizon is included; but how do you know in what direction an object is lying?"

"Simply by the position of this board. It revolves by the same magnetic influence that causes the compa.s.s card always to point to the magnetic-north, only here we have made corrections for the variation of the compa.s.s. The only drawback is that objects to the south are shown inverted on the board, but with a little practice one soon gets accustomed to this. It is like the inverted image on the ground gla.s.s of a camera, and to an experienced photographer that state of affairs presents no difficulty. Here we are: right abeam on the starboard hand you can see Bull Point, the ordnance depot. When were you last up the river Tamar, might I ask?"

"Quite two years ago."

"And it is more than seven since last I saw Saltash Bridge. There have been vast changes, and I suppose had you been at the periscope all the way up the Hamoaze you would have noticed a difference in the aspect of the place."

"I see that they've covered in the magazines with earth," said Hythe.

"That's for protection against attack from aerial craft."

"And it is the same in Devonport and Keyham Yards. There's no doubt the British nation has developed an air-invasion panic. For instance: years ago all the building slips in the Royal Dockyards were roofed in. I can remember the huge sloping roofs with their skylights arranged after the manner of the ports of an old three-decker man-of-war. Early in the present century these roofs were removed, and the slips were left entirely open and uncovered. Now what do I see? Every dock, every slip, every Government workshop of importance is housed in with a bomb-proof steel roof. And with one touch of my little finger I could do more damage, and without being seen, to that place yonder than the combined aerial fleets of Germany and Austria. But see, we are in sight of Saltash Bridge. Just below that structure I mean to bring up for the night. I regret, Mr. Hythe, I cannot give you an opportunity to stretch your legs upon Devon or Cornish soil, but I trust that you will realize that circ.u.mstances prevent my so doing."

The "Aphrodite" sank to the bed of the river between the lofty bridge and the chains of the floating-bridge plying between the village of Saltash and the left bank of the Tamar. Here in fifty-six feet of water she was in absolute safety, and since there was no occasion to recharge her acc.u.mulators, she had chosen a berth where she was partially protected from the full force of the tide by water-pipes that are laid across the bed of the river by the side of the Albert Bridge.

Just before dinner Hythe asked if he could see his man, O'Shaunessey, and to this request Captain Restronguet made no objection. The sub could, of course, have had the Irishman sent to the cabin allotted to his personal use, but somehow he preferred to see the man in the crew's quarters. With so many mechanical and electrical contrivances about her Hythe fought shy of conversing with O'Shaunessey in his cabin; there might, he thought, be some device whereby the captain could overhear every word.

The men's living-room presented quite an animated scene when Hythe entered. Tea had just been finished, and the crew who were on "watch below" were playing cards, dominoes, and billiards, or else reading or talking. A large electric gramophone was reproducing the latest songs, interspersed with the old-time seamen's chanties that seemed utterly out of place within a submarine. Captain Restronguet, recognizing the demoralizing effect of ennui, had taken every safeguard to maintain a cheerful demeanour amongst his men.

Although nearly every one was smoking there was hardly any sign of fumes. Overhead three electric fans were expelling the smoke, but how the vapour was ejected from the vessel Hythe could not imagine.

O'Shaunessey was sitting at a table, eagerly conversing with two of the crew. The Irishman's sense of humour appealed to his new comrades, and with an adaptability that contrasted forcibly with his belligerent att.i.tude earlier in the day, O'Shaunessey was cracking jokes right and left.

As the young officer entered, the crew stood up--not with the alacrity of naval men, but all the same with a sense of respect towards their superiors in rank.

"Carry on, men," exclaimed Hythe, and crossing over to where O'Shaunessey stood he asked him how he fared.

"Sure, an' I've fallen on me fate this time, sorr," replied the Irishman with a grin. "They are feeding me up like O'Leary's pig, an' it's a drap o' the old cratur they serve out at eight bells, which is more to me loikin' than navy rum--after the steward's wathered it."

The men to whom O'Shaunessey had been talking smiled broadly at this, and considerately moved away so that the sub and the seaman could converse in private. Hythe was beginning to be afraid that the Irishman was too contented to make an effort to obtain his liberty should occasion arise; but lowering his voice O'Shaunessey continued,

"All the same, sorr, it's to be back aboard the 'Investigator' that I'm wanting. 'Ave you any idea wan they'll let us out o' this?"

"Not in the least, O'Shaunessey. Nevertheless we must try to get clear as soon as possible, unless I receive definite orders to the contrary."

"Definite orders to the contrary, sorr? From where, may Oi make so bold as to ask?"