About eight o'clock, as the half-wrecked victors and vanquished were slowly struggling into the half-ruined harbour, five winged shapes became visible against the grey sky over Calais, rapidly growing in size, and a few minutes later two more appeared, approaching from the north-east. They, alas, were the heralds of a fate against which all the gallantry and skill of Britain's best sailors and soldiers would fight in vain.

The two from the north-east were, of course, the Flying Fish and the See Adler; the others were those which had been ordered to load up at the Calais depot, and complete that victory of the Allied Fleets which the science and devotion of British sailors had turned into utter defeat.

John Castellan, standing in the conning-tower of the Flying Fish, looking down over sea and land through his prismatic binoculars, suddenly ground his teeth hard together, and sent a hearty Irish curse hissing between them. He had a complete plan of the operations in his possession, and knew perfectly what to expect—but what was this?

Dover and its fortifications were in ruins, as they ought to have been by this time; but the British Flag still floated over them! The harbour was almost filled with mutilated warships, and others were slowly steaming towards the two entrances; but every one of these was flying the White Ensign of England! There was not a French or German flag to be seen—and there, all along the coast, which should have been in the possession of the Allies by now, lay the ragged line of helpless hulks which would never take the sea again.

What had happened? Where were the splendid fleets which were to have battered the English defence into impotence? Where was the Reserve, which was to have convoyed the transports across the narrow waters? Where were the transports themselves and the half million men, horses and artillery which to-day they were to land upon the stricken shores of Kent?

With that marvellous intuition which is so often allied with the Keltic genius, he saw in a flash all, or something like all, that had really happened as a consequence of the loss of the depot ship at Spithead, and the venting of his own mad hatred of the Saxon on the three defenceless towns. The Channel Fleet had come, after all, in time, and defeated Admiral Durenne's fleet; the Reserve cruisers had escaped, and Portsmouth had been re-taken!

Would that have happened if he had used the scores of shells which he had wasted in mere murder and destruction against the ships of the Channel Fleet? It would not, and no one knew it better than he did.

Still, even now there was time to retrieve that ghastly mistake which had cost the Allies a good deal more than even he had guessed at. He was Admiral of the AËrial Squadrons, and, save under orders from headquarters, free to act as he thought fit against the enemy. If his passion had lost victory he could do nothing less than avenge defeat.

He ran up his telescopic mast and swerved to the southward to meet the squadron from Calais, flying his admiral's flag, and under it the signal:

"I wish to speak to you."

The Flying Fish and the See Adler quickened up, and the others slowed down until they met about two thousand feet above the sea. Castellan ran the Flying Fish alongside the Commodore of the other Squadron, and in ten minutes he had learned what the other had to tell, and arranged a plan of operations.

Within the next five minutes three of the seven craft had dropped to the water and disappeared beneath it. The other four, led by the Flying Fish, winged their way towards Dover.

The aËrial section of the squadron made straight for the harbour. The submarine section made south-westward to cut off the half dozen "lame ducks" which were still struggling towards it. With these, unhappily, was the Scotland, the huge flagship of the North Sea Squadron, which still full of fight, was towing the battleship Commonwealth, whose rudder and propellers had been disabled by a torpedo from a French submarine.

She was, of course, the first victim selected. Two Flying Fishes dived, one under her bows and one under her stern, and each discharged two torpedoes.

No fabric made by human hands could have withstood the shock of the four explosions which burst out simultaneously. The sore-stricken leviathan stopped, shuddered and reeled, smitten to death. For a few moments she floundered and wallowed in the vast masses of foaming water that rose up round her—and when they sank she took a mighty sideward reel and followed them.

The rest met their inevitable fate in quick succession, and went down with their ensigns and pennants flying—to death, but not to defeat or disgrace.

The ten British submarines which were left from the fight had already put out to try conclusions with the Flying Fishes; but a porpoise might as well have tried to hunt down a northern diver. As soon as each Flying Fish had finished its work of destruction it spread its wings and leapt into the air—and woe betide the submarine whose periscope showed for a moment above the water, for in that moment a torpedo fell on or close to it, and that submarine dived for the last time.

Meanwhile the horrors of the past afternoon and evening were being repeated in the crowded harbour, and on shore, until a frightful catastrophe befell the remains of the British Fleet.

John Castellan, with two other craft, was examining the forts from a height of four thousand feet, and dropping a few torpedoes into any which did not appear to be completely wrecked. The captain of another was amusing himself by dispersing, in more senses than one, the helpless, terror-stricken crowds on the cliffs whence they had lately cheered the last of Britain's naval victories, and the rest were circling over the harbour at a height of three thousand feet, letting go torpedoes whenever a fair mark presented itself.

Of course the fight, if fight it could be called, was hopeless from the first; but your British sailor is not the man to take even a hopeless fight lying down, and so certain gallant but desperate spirits on board the England, which was lying under what was left of the Admiralty Pier, got permission to dismount six 3-pounders and remount them as a battery for high-angle fire. The intention, of course, was, as the originator of the idea put it: "To bring down a few of those flying devils before they could go inland and do more damage there."

The intention was as good as it was unselfish, for the ingenious officer in charge of the battery knew as well as his admiral that the fleet was doomed to destruction in detail—but the first volley that battery fired was the last.

A few of the shells must have hit a French Flying Fish, which was circling above the centre of the harbour, and disabled the wings and propellors on one side, for she lurched and wobbled for an instant like a bird with a broken wing. Then she swooped downwards in a spiral course, falling ever faster and faster, till she struck the deck of the Britain.

What happened the next instant no one ever knew. Those who survived said that they heard a crashing roar like the firing of a thousand cannon together; a blinding sheet of flame overspread the harbour; the water rose into mountains of foam, ships rocked and crashed against each other—and then came darkness and oblivion.

When human eyes next looked on Dover Harbour there was not a ship in it afloat.

Dover, the great stronghold of the south-east, was now as defenceless as a fishing village, and there was nothing to prevent a constant stream of transports filled with men and materials of war being poured into it, or any other port along the eastern Kentish coast. Then would come seizure of railway stations and rolling stock, rapid landing of men and horses and guns, and the beginning of the great advance.

On the whole, John Castellan was well satisfied with his work. He regretted the loss of his consort; but she had not been wasted. The remains of the British fleets had gone with her to destruction.

Certainly what had been done had brought nearer the time when he, the real organiser of victory, the man who had made the conquest of England possible, would be able to claim his double reward—the independence of Ireland, and the girl whom he intended to make the uncrowned Queen of Erin.

It was a splendid and, to him, a delicious dream as well; but between him and its fulfilment, what a chaos of bloodshed, ruin and human misery lay! And yet he felt not a tremor of compunction or of pity for the thousands of brave men who would be flung dead and mangled and tortured into the bloody mire of battle, for the countless homes that would be left desolate, or for the widows and the fatherless whose agony would cry to Heaven for justice on him.

No; these things were of no account in his eyes. Ireland must be free, and the girl he had come to love so swiftly, and with such consuming passion, must be his. Nothing else mattered. Was he not Lord of the Air, and should the desire of his heart be denied him?

Thus mused John Castellan in the conning-tower of the Flying Fish, as he circled slowly above the ruins of Dover, while the man who had beaten him in the swimming-race was sitting in the observatory on far-off Whernside, verifying his night's observations and calculating for the hundredth time the moment of the coming of an Invader, compared with which all the armed legions of Europe were of no more importance than a swarm of flies.

When he had satisfied himself that Dover was quite defenceless he sent one of the French Flying Fishes across to Calais with a letter to the District Commander, describing briefly what had taken place, and telling him that it would be now quite safe for the transports to cross the Straits and land the troops at Portsmouth, Newhaven, Folkestone, Dover and Ramsgate.

He would station one of his airships over each of these places to prevent any resistance from land or sea, and would himself make a general reconnaissance of the military dispositions of the defenders. He advised that the three Flying Fishes, which had been reserved for the defence of the Kiel Canal, should be telegraphed for as convoys, as there was now no danger of attack, and that the depot of torpedoes and motive power for his ships should be transferred from Calais to Dover.

As soon as he had despatched this letter, Castellan ordered two of his remaining ships to cruise northward to Ramsgate, keeping mainly along the track of the railway, one on each side of it, and to wreck the first train they saw approaching Dover, Deal, Sandwich and Ramsgate from the north. The other two he ordered to take the Western Coast line as far as Portsmouth, and do the same with trains coming east.

Then he swung the Flying Fish inland, and took a run over Canterbury, Ashford, Maidstone, Tonbridge, Guildford and Winchester, to Southampton and Portsmouth, returning by Chichester, Horsham and Tunbridge Wells.

It was only a tour of observation for the purpose of discovering the main military dispositions of the defenders—who were now concentrating as rapidly as possible upon Folkestone and Dover—but he found time to stop and drop a torpedo or two into each town or fort that he passed over—just leaving cards, as he said to M'Carthy—as a promise of favours to come.

He also wrecked half a dozen long trains, apparently carrying troops, and incidentally caused a very considerable loss of good lives and much confusion, to say nothing of the moral effect which this new and terrible form of attack produced upon the nerves of Mr Thomas Atkins.

When he got back to Dover he found a letter waiting for him from the General informing him that the transports would sail at once, and that his requests would be complied with.