CHAPTER XXIV

A FRUSTRATED PLOT

THE recovered reciprocators were none the worse for their prolonged submersion, thanks to the protection afforded by the steel cylinders in which they were encased.

A diver having removed them from the body of the ill-fated airman, the wrecked monoplane was released and allowed to sink once more to the bottom of the sea.

The aviator's body was brought on board the _Olive Branch_ in order that it might be given a decent burial, and then it was that an astonishing discovery was made.

The man was not an American. Papers found on him, carefully concealed in the double thickness of his indiarubber coat, revealed the fact that he was the agent of a certain European power, and that it was his intention to find out as much about the _Olive Branch_ as he was able to do. The flight across the Straits of Messina was part of a prearranged plan, and, though his fall into the sea under the influence of the Z-rays was not strictly in accordance with his programme, it materially helped to mature the plot that had all but succeeded.

The damage done to the Z-rays apparatus was considerable, necessitating the removal of the diagram board and the wires between the dynamo and the conning-tower. While this was being done the ZZ-rays were consequently out of action, hence Captain Brookes's anxiety to have the work put in hand without a moment's delay.

In this partially crippled state advantage was taken of the proximity of the Santorin Islands to clear the cruiser's under-body of the marine deposit that was already beginning to have an appreciable effect on her speed.

Practically the whole of these islands are of volcanic origin, sulphur springs, being strongly in evidence around the shores of Port Megalos, while the water possesses the property of killing and removing in less than thirty-six hours the weeds and barnacles that adhere to a ship.

"What do you say to a run ashore, gentlemen?" asked Captain Brookes of several of the officers on the afternoon of their arrival. "I'm told the crater is very interesting."

"I, for one, will be very glad of the opportunity, provided I can be spared," replied Sinclair.

"And I," exclaimed Gerald, Stockton, Temple, and Slade in chorus.

"Very well, only be careful not to go too close to the sulphur springs, and beware of loose stones rolling down the mountain. You will be practically in sight of the ship the whole time, so keep a good look-out in case I have to make a signal for recall."

Two hours later, by dint of much exertion and considerable agility, the party of officers gained the edge of the crater. For some time they remained looking at the scene of desolation.

"What's that, by Jove!" exclaimed Jack Stockton, pointing to an elongated yellow object swaying in a deep hollow a few hundred yards away. The others looked in the direction indicated.

"It's an airship--one of the Zeppelin type," said Gerald. "What on earth is it doing in this part of the globe?"

"I wish I'd brought my marine glasses," remarked Sinclair. "This looks like an interesting discovery. She's anchored, I think."

"Ay, and there are some men coming this way; they've just descended by a rope ladder. I wonder if they have spotted us?"

"I don't think so. Look here, you fellows, they mean mischief! Suppose we take cover and watch their little game?"

The only shelter worthy of the name was afforded by a clump of withered thorns. Foliage there was none, but by lying flat on the ground and keeping behind the thick uncovered roots, the officers could follow the movements of the men of the mysterious airship.

Evidently the clump was the objective of the strangers, since from it they could command a view of the _Olive Branch_ without appearing on the skyline. The new comers were three tall, bearded men dressed in a brown uniform. One carried a revolver in a pouch, the others were apparently unarmed; all had field-glasses slung over their shoulders.

Unsuspectingly they stopped at the clump of thorns, only a few tangled branches separating them from Gerald and his comrades. Out came their glasses, and with them glued to their eyes the chance of detecting the concealed officers was materially lessened.

"Yes, there she is," exclaimed one of the strangers, speaking in a guttural tongue that both Gerald and Sinclair were conversant with. "Adolphe was right this time."

"Looking at her from here, sir, one would not imagine her to be such a formidable ship."

"Appearances are deceptive, Captain Dorge. However, there she is, and now is our opportunity. Once we settle with her our chances against England are wonderfully improved."

"Will forty kilos of the explosive be sufficient?"

"It will wipe her out of existence. We must be sharp, for the moon rises at two."

"If we blunder?"

"There will be no blunder. I'll bring the 'Voertwards' immediately above her, and drop to within thirty metres of her deck. They will never expect an attack in this harbour, especially from the sky."

Gerald's grasp tightened on Sinclair's shoulder. That officer nudged Temple in a manner that required no verbal explanation; while Stockton, who had observed the signal, was not slow to comprehend.

"Now!" shouted Sinclair.

Simultaneously the four men sprang to their feet, burst through the intervening bushes, and threw themselves on the astonished foreigners.

The man addressed as Captain Dorge made as if to draw his revolver, but Gerald had already seized him round the waist, while Jack Stockton deftly took possession of his weapon. In an instant he was capsized, Stockton sitting on his chest so that he could only writhe helplessly in the dust.

Temple, a strapping great Scot, had little difficulty in overpowering his antagonist, but Sinclair found all his work cut out in tackling his man. Fiercely they struggled, the stranger striving to grip his adversary by the throat. Failing that, he inserted his fingers in the lieutenant's hair and tried to gouge his eyes out with his thumbs--a continental trick that Sinclair was conversant with.

The first lieutenant's left arm shot out straight from the shoulder, and, taking his antagonist fairly in the chin, sent him reeling a dozen paces ere he fell like a log.

"Now what's to be done?" asked Gerald breathlessly, as he wiped the perspiration from his forehead.

"Done? Why, drag the bounders back to the ship," replied Sinclair. "We've three important hostages for the airship's good behaviour."

"Easier said than done."

"Not when you know the way, but we must look alive, for I see yonder gentleman is recovering from the effects of my knock-out blow. I wonder if the other fellows belonging to the airship have spotted us?"

So saying, Sinclair relieved the two prisoners of their belts, and, ordering the men to stand side by side, he fastened the left arm of one to the right arm of the other by means of the leather straps, tying their thumbs together by means of a piece of thin cord as an additional safeguard.

Meanwhile Gerald and Stockton had raised the semi-dazed officer, while Temple brought up the rear with the captured revolver well in evidence.

It had taken nearly two hours to climb the crater, but the descent occupied barely twenty minutes.

Smothered in clouds of pumice dust, continually dodging enormous boulders that rolled down the mountain side, the officers of the _Olive Branch_ and their captives pursued their headlong descent, and on gaining the beach they found that a boat had already been despatched to bring them off to the ship.

"What has happened, gentlemen?" asked Captain Brookes as the party gained the quarter-deck. "I was watching you through my glasses, and could see that you were having an encounter of some sort."

Briefly the "first luff" made his report. The captain's brows clouded.

"This is bad news," he remarked. "Whatever design these people have against Great Britain is evidently a secret. I've been in communication by wireless with our Swanage agent, and he assures us that there is no sign of international complications. However, it's lucky you nipped this little plot in the bud, for I have no doubt that that airship would deliberately violate all the etiquettes of neutrality. I'll ask our prisoners a few questions."

"I am Hans von Rippach," replied the man who was evidently the senior officer of the airship.

"Herr Hans von Rippach, I salute you," rejoined Captain Brookes, without betraying the fact that he understood the nature of the foreigner's reply, though he shrewdly suspected that his prisoner was a member of the Royal House of a powerful European State. "Might I inquire the reason why you proposed to attack my vessel treacherously in neutral waters?"

"I refuse to offer explanations to a pirate," replied the prisoner, rudely.

Finding that it was useless to attempt to gain further information, Captain Brookes ordered the captives to be removed and confined in a cabin under an armed guard.

"Couldn't we have a smack at the airship, sir?" asked Lieutenant Sinclair. "A six-pounder could be taken ashore and dragged up to yonder ridge without much trouble."

"We might harm some of the inhabitants of the island," replied Captain Brookes. "There's bound to be a crowd gathered around to see the sight."

"I venture to suggest that the crew have kept them at a respectful distance, sir."

"I'll not take the risk. If the airship ascends I'll wing her sure enough, not otherwise. But I mean to get under way at once and head at top speed for English waters. There's mischief brewing; of that I feel certain."

Ere nightfall the _Olive Branch_ had cleared Santorin Harbour and was tearing towards the Straits of Gibraltar. The English agent at Swanage was kept constantly in touch by means of wireless, greatly to that individual's annoyance, since he saw no reason for Captain Brookes's continuous messages. But, four hours after clearing the Straits, a wireless was received that caused the blood of every member of the crew of the _Olive Branch_ to surge madly through his veins. It was brief and yet to the point: "Triple Alliance has commenced hostilities against Great Britain."