'Which way does it lie ?'

The man pointed. 'Over there. That's the German coast, but the sandbank on the other side is nearer, I think. If you're going to swim to it you'd better start.'

'Why-is there any hurry 2'

The man was looking past Biggles at something beyond him, and turning to see what it was, Biggles saw the drifter, the existence of which he had completely forgotten. It was moving dead slow through the water picking up survivors ; its boats had been lowered and were doing the same thing. He had no desire to be picked up, for he had a shrewd idea of what that would mean in the end-particularly after the sinking of the Leipzig by one of his machines. He preferred to take his chance on the sandbank, or even the mainland, where, if he was found, he might pa.s.s as a survivor of the ill-fated ship until he could make plans to escape. There was always a chance that he might be able to steal a small boat and get back to Bergen Mt.

'Thanks,' he told the German gratefully, and struck off into the darkness.

'Lebewohl! Good luck!' called the German after him.

For some time Biggles did not look back, but devoted himself to getting clear of the danger zone, the position of which he could judge roughly by the frequent hails of men still in the water as they tried to attract the attention of the rescuers. There was no moon, but in the light of the stars he could just make out the dark hull of the drifter. But of the Leipzig there was no sign. In a vague sort of way he wondered what had happened to von Stalhein, but he soon dismissed him from his mind, for the water was cold, and although he was a strong swimmer, he knew that if he did not soon reach land he might succ.u.mb to exposure. So settling down to a steady breast stroke, which he knew from experience he could keep up for a long time, he struck out in the direction in which, according to the sailor, the sandbank lay. At present he could not see it; not that he expected to, for it was too dark to see far. It was disconcerting, this swimming through the darkness towards an unseen objective, for should he miss it his position would be hopeless ; at least, from what he had seen of the Baltic while flying over it, he would not have given much for his chance of being picked up by a ship.

An hour later he was still swimming, but not so strongly, for his body was fast becoming numb from the cold, and he dare not float to rest himself, as he could have done had the water been warmer. Shortly afterwards, however, he found it imperative to change his stroke, and in doing so he heard the sound which he had been hoping to hear-the measured beat of surf on the sandy sh.o.r.e.

With a prayer of thankfulness he struck out with renewed vigour, and a few minutes later found him staggering through shallow water to the beach. Not until he had crawled up on the sand did he realize how far he was spent; but even then what he feared most was that he might collapse from cold, for the night air was chilly. So with the object of restoring his circulation by the only means available, he set off at a jog-trot along the lonely beach, which seemed to stretch to infinity in front of him. He was deadly tired, but still he ran on, deriving some comfort from the warmth that his exercise was producing.

How far he ran he did not know. Nor did he care. He only knew that he seemed to have been running for hours when just ahead he observed some fairly high sand-dunes, and towards these he directed his steps, hoping to find shelter where he could take a breather.

Breaking into a sprint to satisfy himself that he still had it in him, he dashed round the foot of the first dune, and collided with stunning force with somebody coming the other way.

Tired as he was he was unable to keep his balance, and after a final stumble, in which he caught a glimpse of a dark human form, he plunged headlong into the loose sand.

Quick as he was getting on his feet, the other was quicker, and he went over backwards again with a gloved hand pressed savagely over his mouth. Gripping his a.s.sailant with his hands, and doubling his knees under him, he endeavoured to fling him off, but only succeeded in causing them both to roll over and over down the sloping sand.

They arrived at the bottom with Biggles underneath. He saw an arm raised to strike. The b.u.t.t end of a revolver showed for an instant against the sky, and he clutched at it desperately. His a.s.sailant sought to free his arm, but just as furiously Biggles held on to it. Then came the end. But it was not the end Biggles expected, for, the struggle coming on top of his previous exertions, he was on the point of collapse.

It came when his opponent suddenly shouted, 'Hi! Briny! Help!'

Algy,' gasped Biggles weakly. 'Get off my chest, you maniac!'

CHAPTER XIII.

AN ALARMING DISCOVERY.

THE pressure on Biggles's chest relaxed with amazing prompt.i.tude.

Algy was incapable of speech, and for a while he could only yammer foolishly. 'What are you doing here ?' he managed to get out at last.

Biggles lay flat on his back, panting heavily. 'What do you think ? Making sand-castles with my little spade and bucket? What are you playing at, anyway ?'

Oh, I'm just collecting pretty pebbles for the kids to play marbles with,' replied Algy. 'As a matter of fact, I'm on my way to blow up the dump.'

'Dump ? What' dump ?'

Ah! Of course, I forgot, you don't know about that. Briny found a dump.'

'Briny ? Where is Briny ? What's he been doing ? Am I going crazy or are you ? You talk as if he'd found a dump kicking about on the beach.'

As if in answer to the questions, Briny himself charged round the dune, swinging a rifle in a most dangerous manner.

'Be careful what you're doing with that thing, you fool,' snapped Biggles irritably, for what with shock and fatigue he was in no mood to be polite.

Briny stopped with ludicrous suddenness, the rifle poised. Then, slowly, it dropped to the ground. 'Luv a duck, sir, if it ain't the C.O.,' he gasped. 'What have you been doing, sir, if I may make so free as to ask ?'

'Riding round the front in a hansom cab with Hitler,' grated Biggles with bitter sarcasm. '

It's time we stopped asking fool questions and got this thing straightened out,' he added with a change of tone. 'I'll start. I found the motor-boat, but was captured by von Stalhein in a drifter and arrived on the Leipzig just as somebody was thoughtful enough to sling a mouldy in her ribs. I jumped into the sea and swam here. That's all.'

I slung the mouldy,' admitted Algy.

'Thanks. You'll never sling a better one as long as you live,' declared Biggles. tell you why later on.'

I found Briny stranded on this sandbank,' explained Algy. 'On the way back to the base we found the remains of your machine, so thinking you were a gonner I went mad dog. I had a crack at the Leipzig first. Then I went home for a time-bomb. Oh, I forgot to say that when I picked up Briny here we found a dump-a sort of Hun naval store. We were going to blow it up when I ran into you. I brought Briny along to guard the machine while I did the dirty work.'

I see. That explains things,' said Biggles, rising stiffly to his feet. 'Somebody will have to lend me a jacket. I'm cold. I've been swimming for an hour or more in this perishing ditch.'

Briny took off the flying jacket he was wearing and pa.s.sed it over. 'I remember once ' he began.

'Then forget it,' cut in Biggles, putting on the coat. 'And now, if somebody would be kind enough to take me home, I should like to warm my tootsies by the stove.'

'What about the dump ?' asked Algy. 'I've got the time-bomb here.'

'You can stick it in a crab hole or play hop-scotch with it for all I care. I don't feel like fooling about any dumps, and I've heard all the explosions I want for one day. Let's get back. I'll send Ginger to attend to the dump.'

'You won't,' replied Algy promptly.

'Why not?'

'He's missing.'

'Missing! Since when ?'

'n.o.body 's seen him since we took off early this morning.'

Is the spare machine still in the cave ?'

'Yes.'

'Then he must be on the island somewhere. Suffering Mike! What sort of a squadron have I got ? What does the young a.s.s think he's at-a picnic ?'

'When you find him you can ask him.'

Biggles thought for a moment. He was not seriously upset about Ginger, for if the Platypus was still at its moorings it was obvious that he could not be far away, for the simple reason that he had no means of leaving the base. It struck him, however, that if the dump was to be destroyed, now was the time to do it, for it seemed certain that the Germans would cause a search to be made for him, and the sandbank, being the land nearest to where the Leipzig was sunk, would be one of the first places they would look at. He decided, therefore, that if anything was to be done about the dump, now was the best time, for to return later might result in an encounter with a search party sent out to look for him. Indeed, he was only too well aware of how dangerous their whole project had already become. It was, in fact, precarious, now that von Stalhein knew they were operating in the district-a.s.suming that he had survived the Leipzig disaster. He knew the German well enough to know that, actuated as he was by personal motives as well as those of patriotism, he would not rest until he had located their base; and it could be only a question of time before he examined Bergen Ait. The fact that the islet was supposed to be the property of a neutral state would weigh little with a man as thorough and relentless as Erich von Stalhein. However, he refrained from depressing the others by communicating to them these disconcerting thoughts.

All right,' he said at last, 'I'll tell you what we'll do. For the three of us to try to squeeze into the machine is going to be a difficult business, particularly as I'm not dressed for what you might call skylarking. Algy, suppose you take Briny home and then come straight back bringing my spare kit with you. You ought to make the round trip inside an hour. I'll get everything ready here for the big bang the moment you return. That seems to be the easiest way.'

As you say,' agreed Algy.

'Where is the dump ?'

Algy pointed. 'About half a mile along the beach.'

I see. To save our legs you might as well land a bit nearer to it when you come back. By the way, what exactly does this dump consist of ?'

Algy described what he had seen.

Biggles's eyes opened wide. 'It sounds to me as if there ought to be some stuff there that we could use ourselves. I mean, we might find ourselves out of petrol one day, in which case we should be glad to have a reserve supply. Before blowing the place up I certainly think we ought to have a closer look at what it contains.'

Algy nodded. 'I didn't think of that. But you can't get into it. It 's locked up.'

'You say it 's made of corrugated iron ?'

'That 's right.'

'Then with a drill and a hack-saw we ought to have no difficulty in cutting a hole through the side. We may as well try it, anyway. You bring the tools back with you. Bring a torch and anything you think might be useful. If we find the job of getting in is too much for us we'll give it up and blow the place sky high as you originally intended. But we mustn't stand here talking any longer. You get off and get back as quickly as you can.'

Algy thought the plan was a sound one, so after settling a few minor details, he returned to the machine, taking Briny with him.

Biggles was left alone on the sandbank. As soon as he heard the machine take off, he picked up the time-bomb, which was still lying where it had fallen when the collision had knocked it out of Algy's hand, and started off towards the dump. The moon was now creeping up over the horizon, so it did not take him long to find the shed and the adjacent moorings, which he examined with considerable interest. He then went round to the rear wall, where he arranged the bomb, for he thought it would be as efficient there as anywhere if it were decided to use it. After that, as there was nothing more he could do, he began making a closer inspection of the building.

He did not learn much, however, for he soon discovered what Algy already knew-that there were no windows. He suspected that there were skylights, but he had no means of getting on the roof-not that he made any serious attempt to do so, realizing that the interior would be in utter darkness.

Having nothing to do now but wait, it was with profound satisfaction that he heard the hum of Algy's engine, really before he expected him. He walked briskly towards the sea, and by the time Algy had landed, and taxied into a sheltered creek about two hundred yards away, he had joined him.

Algy tossed him a vacuum flask. 'Take a swig of that,' he said. It's hot coffee-it should warm you up. Here's your kit,' he added, throwing a bundle after the flask.

Biggles began getting into his clothes as quickly as he could, from time to time taking gulps of coffee with grateful relish. Is Ginger back yet ?' he inquired.

'No.'

Biggles paused for a moment in what he was doing. 'I don't like the sound of that,' he said slowly. 'He wouldn't stay away all this time if he could get back. I'm afraid he's met with an accident.'

'Briny and the Flight-Sergeant have hunted high and low for him-in fact, they're still looking.'

Biggles resumed his dressing. 'This squadron of mine doesn't seem to be living up to its name,' he said bitterly. 'There hasn't been much boomeranging about it lately. Apart from losing two of our machines, we seem to have gone out of our way to scatter ourselves all over the blinking Baltic. We'd better not waste too much time here. Did you bring the tools ?'

Algy, who had climbed down from the machine, held them up. 'I've got a length of line in my pocket, too, in case we have to get down through the skylight.'

'Good!' said Biggles, putting on his flying-coat. 'Let's go and rip the hide off this tin toy-shop of Mister Hitler's.'

They were soon at work, choosing the rear wall, with a good deal more noise than Biggles liked, but making such good progress that in half an hour, by levering up the piece they had cut, they were able to crawl through into the interior of the building.

Biggles flashed the torch around as Algy got through behind him. 'Shades of Guy Fawkes!' he e.j.a.c.u.l.a.t.ed. 'What a collection. We really ought to save this little lot for firework day.'

He began walking round, turning the light of the torch on bombs, torpedoes, sh.e.l.ls, machine-guns, sub-machine-guns, and every conceivable form of ammunition. But what interested him more than these were the fuel tanks, and the carefully labelled collection of spare parts and accessories for all sorts of marine craft. With the painstaking thoroughness of a reconnaissance pilot, he made a mental note of everything he saw as they walked on slowly through the corridors. He pointed to a steel airscrew. 'Aircraft evidently use this place as well as submarines and destroyers,' he said. 'I don't know what to do about it, and that's a fact. It might do us a bit of good one day if we left the stuff here; on the other hand, it might do the enemy a lot more harm if we destroyed it. I've a good mind to radio Colonel Raymond and ask him for instructions.

He ought to know about it, anyway. I He broke off suddenly, in a tense att.i.tude. The light went out as he switched it off, leaving them in darkness.

It sounds as if somebody has found my machine,' said Algy in a low voice, for there was no mistaking the sound that had alarmed them. It was an aero-engine.

It isn't your machine. There's more than one,' returned Biggles in a hard voice. 'It sounds to me like a formation-flying low, too.'

'They're coming this way,' declared Algy a moment later.

Biggles was still listening intently. 'I don't think it's a formation after all,' he said slowly. '

I should say it's a big multi-engined job.'

As he spoke the roar of the engines died away, but they could still hear the wail of wind through wires.

It would be a joke if it was coming here, wouldn't it ?' murmured Algy.

It might be your idea of a joke, but not mine,' replied Biggles curtly. 'When I first saw the Baltic I thought it was a pretty deserted place, but lately it seems to be swarming with vehicles of one sort and another. That machine's coming a lot too close for my liking.

We'd better get outside.'

I hope they don't spot my machine.'

I shouldn't think there's much chance of that in this light. Come on, let's get outside. I daren't use the torch; they'd spot it through the skylight; mind you don't knock your eye out on the blunt end of a crankshaft. Keep close to me. I think I can find my way to the hole.' So saying, Biggles began groping his way towards the spot where they had effected an entrance.

Some time before they reached it, it became obvious that even if the aircraft did not actually intend landing, the pilot was gliding down to survey the spot, for the metal building vibrated with noise. Consequently, it was with more haste than dignity that they scrambled through the hole and stared up into the starlit heavens.

They were not long finding the aircraft-for, as Biggles had surmised, it was a single machine.

With its navigation and cabin lights ablaze, a fourengined flying-boat was turning with the majestic deliberation of a battleship towards the anchorage that adjoined the shed.

It would decide to arrive at this moment, wouldn't it ?' said Biggles savagely, as he forced down the jagged metal flap which they had raised to get inside the building. 'Look out! Get down 1'

He flung himself flat, his body pressed close against the corrugated iron, as a parachute flare burst a hundred feet over their heads and flooded the scene with dazzling white light. And thus they were compelled to remain until the keel of the giant flying-boat kissed the water, and surged on towards the wide double doors of the supply depot.

The instant the light exhausted itself Biggles was on his feet. He started to move forward, but pulled up short. 'Where 's the time-bomb ?' he said tersely. 'I put it down here.'

I took it inside with me. I thought if we used it, it would make a better job of things there.'

Biggles muttered something under his breath. I suppose you acted for the best,' he conceded, 'but we daren't go in there now to fetch it. I doubt if we could find it, anyway, without a light. If they come across it there'll be a fine old hullaballoo. We'd better get back to your machine ready for a snappy take-off.'

By this time the huge aircraft had taxied right up to the building. Its propellers stopped as the pilot switched off the ignition, and it was obvious that the crew were about to come ash.o.r.e. Its lights reflected on the water, and the sound of voices came clearly through the still night air.

Biggles caught Algy by the arm, and together they ran to the nearest sand-dune, from where they made their way quickly to the place where they had left the Didgeree-du.

There was no particular need for caution, for they knew that their presence was unsuspected, and it was natural to suppose that the German airmen were too taken up with the task of mooring their machine to worry about anything else.