CHAPTER XII

THROUGH THE MINE FIELD

AT the mention of the word "submarine" Gerald felt the blood surge to his temples. It was not the surprise of hearing that the _Olive Branch_ possessed one of these master craft that affected him; he was getting used to surprises. It was the glamour of the enterprise that thrilled him.

For months past Gerald's ambition was to serve in the submarine flotilla. His name had been on the "roster" as a volunteer for the hazardous, yet attractive, service, but up to the time of his leaving the _Calder_ his hope in that direction had not been gratified.

"May I accompany Mr. Palmer, sir?" he asked, bringing his hand to his forehead with professional smartness.

"I think not," replied Captain Brookes. "This is a matter that requires skilled men."

"Very good, sir."

Gerald felt the disappointment keenly, but like a true Englishman he bore the refusal manfully. Not so with Stockton; his face showed unmistakable signs of relief when his chum had been thwarted in his desires to embark in a hazardous craft destined for a still more hazardous enterprise.

The _Olive Branch_ was now within two miles of the entrance to the harbour. On either side of the narrow mouth were stone forts faced with earth, over which floated the Chilian flag--red, white, and blue, with a white star on the upper "canton" nearest the staff. Beyond were the Government works and the low stone houses of the town, while in the distance the snow-capped Andes reared their lofty peaks to a height of 14,000ft.

"Do you think they'll open fire, Mr. Sinclair?" asked Captain Brookes, jerking his thumb in the direction of the forts.

"I don't fancy so, sir," was the reply. "They will trust to their mines. Since the last war these johnnies think twice before tackling an ironclad."

"Very well, then--carry on. Are your men ready, Mr. Palmer?"

"Ay, ay, sir!"

"Then look sharp about it, if we are to warp into the dock before sunset. By the bye, Mr. Tregarthen," he continued, wheeling round and facing Gerald, "have you had any experience of creeping?"

"Plenty of it in the Vernon, sir."

"I've changed my mind; you may go with Mr. Palmer."

Accompanied by Stockton, who, now that his chum was permitted to take part in the expedition, wanted to share in the perils, Gerald followed the lieutenant and a dozen men down to the orlop-deck.

Here, almost amidships, was an oval-shaped steel box, projecting about three feet above the deck. Unfastening a massive securing-bar, one of the men touched a knob, and the huge rubber-lined lid slowly turned on its hinges and disclosed a similar, though slightly smaller, box. It was the conning-tower of the submarine.

To Stockton the next few minutes seemed like a dream. The lid of the conning-tower was raised, and five of the sailors descended into the recesses of the little craft. Palmer then motioned to Gerald to precede him, and with a hasty grasp of the hand Jack bade his friend a silent farewell.

Then Palmer followed, and ere the lid closed with a ponderous clang Stockton saw the dim glimmer of the electric light shining upon a mass of complicated machinery.

"Stand aside, please, sir!" said one of the men who still remained on the orlop-deck.

The cover of the outer box descended, the securing bar was carefully locked, and the sound of inrushing water was borne faintly to Stockton's anxious ears.

"They're off now, sir," added the seaman. "If you go on deck you'll be able to see something of what they're up to."

From the top of the conning-tower, which in lieu of the demolished bridge and charthouse was now the highest practicable coign of vantage, Stockton and several of the officers watched the tip of the submarine's periscope glide slowly along the surface of the water, while some 30ft. in the rear was the tell-tale swirl of the vessel's propeller and the characteristic wake of the submersed craft.

Every available glass was brought to bear upon the receding pole-like object, as it kept an unswerving course straight for the entrance of the harbour.

Suddenly a column of water was thrown 50ft. in the air. Stockton gave an involuntary gasp of horror--what if the submarine had fouled one of the deadly mines?

A minute passed. Even Captain Brookes began to look anxious, for no trace of the periscope was now discernible.

"There she goes again!" shouted one of the men, as another slender column rose high in the air.

Four times this was repeated, then once more came an ominous and prolonged silence. While the attention of all hands was directed towards the harbour the grey, porpoise-like hull of the submarine floundered to the surface less than a cable's length from the port bow of the _Olive Branch_. Thus, having announced her safe return, the little craft disappeared beneath the waves, and, guided by consummate skill and judgment, she glided underneath the hull of her parent ship.

Half an hour later her crew came on deck of the _Olive Branch_.

"All correct, sir," reported Lieutenant Palmer. "Every mine exploded; six in all."

"Very good," replied Captain Brookes. There were volumes of commendation in those two words, and every man who took part in the dangerous enterprise realised the fact.

"We must wait another hour till there's enough water on the bar, so our pilot informs me," continued Captain Brookes. "Mr. Sinclair, I'm going below; please report if anything unusual occurs."

"Well, old chap," exclaimed Stockton as the two friends gained the seclusion of their cabin "how did you get on?"

"Splendidly," replied Gerald, enthusiastically. "The submarine is a masterpiece. This was the mysterious object at which the captain hinted during our inspection of the wireless room. I think I've grasped the principle of it. The submarine is barely 30ft. in length and 8ft. in beam, and is housed in a cavity underneath the ship corresponding with the upper half of the submersible. Apparently its natural buoyancy keeps it adhered to the hull of the _Olive Branch_, but to prevent undue friction when running at full speed there are several steel doors, which, when closed, complete the normal curvature of the ship's bottom. You saw how we entered the submarine?"

"Yes, by means of a watertight door in the orlop-deck, and a corresponding one in the submarine's conning-tower."

"Well, directly I descended into the little craft I noticed that she was propelled by electric motors, of about 35 horse-power I should imagine. Forward there is a bow tube of less than 4ins. in diameter, consequently she can carry twenty small torpedoes to our submarines' four. I noticed that the vessel was submerged by means of water ballast instead of relying upon horizontal rudders, although the latter are utilised when running beneath the surface.

"Directly all hands were aboard Palmer opened a valve, and I saw the pale green light filter through the glass of the conning-tower; we had sunk clear of the _Olive Branch's_ hull. We descended quite 80ft., in fact, almost to the bottom of the sea, for I could see the water discoloured by the muddy sediment caused by the rush of the still ebbing tide. Then the motors were started, and, once well away from the cruiser, Palmer hoisted the periscope, which hitherto had been housed within the submarine.

"'Now, then,' said he, 'you know a mine when you see one, so will you please stand by the conning-tower look-out; I'll keep the vessel on her course by means of the periscope.'

"So saying he descended a short iron ladder and took his stand before a small table coated with highly polished silver. This mirror reflected an erect, right image, or, in other words, a faithful reproduction of the horizon as seen from the surface.

"We were running at six knots, so that taking into consideration the strength of the ebb, our rate over the ground was a bare three knots, thus allowing an ample margin to bring up should we sight an obstruction."

"How far could you see ahead?"

"About 100ft., for the water was fairly translucent in the bright sunshine. Had it been dark we could have used a powerful searchlight.

"Suddenly I caught sight of a barrel-shaped object straining at its sinker and cable like a gigantic long-stalked mushroom. Palmer was instantly at my side, having ordered the motors to be eased down. The principle on which the torpedoes are fired is similar to that by which the guns are discharged on board this ship. I saw the slender, fish-shaped weapon leave the tube and glide towards the mark, but the target being a small one, and oscillating into the bargain, the torpedo missed it by a foot.

"The second shot was successful, and although I did not hear the detonation, the shock was sufficient to make the submarine lurch violently.

"This operation was repeated till we found ourselves right inside the harbour, the wharves and the shore being crowded with people attracted by the unwonted spectacle of the presence of a mysterious battleship in the offing."

"Then it's certain that all the mines have been destroyed?"

"All in the channel, at all events, for we could see the outlines of the shoal on either hand, and not a trace of a mine remained. But there's the engine-room telegraph; we're getting under way once more, so let's go on deck."

On gaining the fo'c'sle the two chums found the Chilian skipper shaking with apprehension and anxiety. He had been led for'ard and was conning the ship under the charge of Lieutenant Sinclair, who was an expert Spanish linguist. The lieutenant communicated the pilot's directions to the quartermaster in the conning-tower, who in turn held the _Olive Branch_ on her course at a steady five knots.

Even then the depth on the bar was so little that for some considerable distance the ship's remaining propellers churned up columns of liquid mud. Cleared for action she slowly approached the harbour, but, as anticipated, there was no sign of resistance from the forts. On the contrary they respectfully dipped their flags, a compliment that the _Olive Branch_ returned by lowering her green and white ensign.

"Mr. Sinclair, will you pipe away the cutter's crew. I want you to take this letter ashore, and your knowledge of their lingo will be useful in case they cannot translate it," said Captain Brookes. "I've told them my requirements, and offer to pay all lawful dock charges and dues. Inform them of events between the two republics, and of our part in the matter."

An hour later Lieutenant Sinclair returned with the information that Captain Brookes's requests were favourably received, and that the _Olive Branch_ could go into dock at once. He also bore the intelligence that the alcalde and the commandante of Talcahuano were about to pay a complimentary visit to the cruiser that had, while engaged in the work of settling the differences between Chili and Peru, inflicted a severe loss upon the fleet of the latter republic.

"Good," remarked Captain Brookes, gleefully. "Nothing could be better, gentlemen. I mean to make use of both the alcalde and the commandante of the town during our stay here."

Without further delay the _Olive Branch_ was warped into dock and shored up. The water was then pumped out, and, as the captain had prophesied, the cruiser was dry-docked before sunset.