Leffens, grasping the side of his fuselage with his left hand, and still holding the machine in a spin, looked back, and saw the Pup spinning down behind him. He knew he could not spin for ever. Sooner or later he would have to pull out or crash into the sun-baked surface of the wilderness.

* The manoeuvre consists of a half roll off the top of a loop thereby quickly reversing the direction of flight. Named after Max Immelman, successful German fighter pilot 1914-1916 with seventeen victories, who was the first to use this turn in combat.

Biggles knew it, too, and waited with the calculating patience of the experienced air fighter. He saw the earth, a whirling band of brown and yellow, floating up to meet him, and saw the first movement of the Pfalz's tail as the German pilot kicked on top rudder to pull out of the spin. With his right hand gripping the firing lever he levelled out, took the silver and blue machine in his sights, and as its nose came up, fired. The range was too close to miss. The stricken Pfalz reared high into the air like a rocketing pheasant as the pilot convulsively jerked the joystick into his stomach; it whipped over and down in a vicious engine stall, and plunged nose first into the earth. Biggles could hear the crash above the noise of his engine, and caught his breath as a cloud of dust rose high into the air.

He pa.s.sed his hand over his face, feeling suddenly limp, and circled round the wreck at stalling speed. In all directions stretched the wilderness, flat, monotonous, and forbidding, broken here and there by straggling camel-thorn bushes. The thought occurred to him that the German pilot might not have been killed outright, and the idea of leaving a wounded man in the waterless desert filled him with horror.

I shall have to go down,' he muttered savagely. 'I don't want to, but I shall have to; I can'

t just leave him.'

He chose an open s.p.a.ce as near as possible to the crash, landed safely, and hurried towards the shattered remains of the German machine. One glance told him all he needed to know. Karl Leffens was stone dead, shot through the head. He was lying in the wreckage with his right hand outflung. His glove had been thrown off, and Biggles caught the gleam of yellow metal. Stepping nearer, he saw that it was the signet ring, shining in the sunlight. Automatically, he stooped and picked it up and dropped it in his pocket with a muttered, 'Might be useful-one never knows.'

Then he saluted his fallen opponent. 'Sorry, Leffens,' he said in a low voice, 'but it was either you or me for it. Your people threw the hammer into the works, so you can't blame anyone but yourself for the consequences.' Then, making a mental note to ask Algy to send out a burying party, he took off and returned to the oasis. But of the R.E.8 there was no sign, so he turned again and headed back towards Zabala.

On the way he unfolded his map and looked up the position of Sidi Arish, and smiled grimly when he saw that it was on the fringe of the area pointed out to him by von Faubourg. 'I hope the Old Man* will think I have done a good morning's work,' he murmured, as he opened his throttle wide and put his nose down for more speed.

* Slang: person in authority, the Commanding Officer.

Chapter 5.

The New Bullet It may have been fortunate for Biggles that by the time he reached Zabala a slight wind had got up and was sweeping low clouds of dust across the sandy expanse that served as the aerodrome, and that its direction made it necessary for him to swing round over the sheds in order to land. But it was not luck that made him look carefully below, and to left and right, as he skimmed in over the tarmac in order to see who was about. Thus it was that his eyes fell on von Stalhein standing alone on the lee side of the special hangar.

There was nothing unusual about that, but with Biggles the circ.u.mstances were definitely unusual, for on the floor of his c.o.c.kpit reposed an object that could hardly fail to excite the German's curiosity if he saw it. It was the explosive charge provided by Major Raymond.

It was not very large; indeed, it would have gone into the side pocket of his tunic; but the bulge would have been conspicuous, and it was not customary for airmen to fly with bulging pockets while canvas slots and cavities were provided in aeroplanes for the reception of such trifles as Very pistols, maps, and notebooks.

Consequently Biggles deliberately overshot and finished his run on the far side of the aerodrome in a slight dip that would conceal the lower part of his machine from watchers on the tarmac. He reached far over the side of the c.o.c.kpit and dropped the bomb lightly on the sand with confidence, for as far as he knew that part of the aerodrome was seldom visited by any one, and the small object would hardly be likely to attract attention if a pilot did happen to see it.

It was as well that he took this precaution, for von Stalhein was waiting for him outside the hangar when he taxied in. Biggles nodded casually as he switched off, and without waiting to remove his flying kit set off in the direction of Headquarters 'Just a minute; where have you been?' von Stalhein called after him.

I have been making a reconnaissance over the Jebel-Tel country-why?' replied Biggles carelessly.

'Did you see anything of Leffens? I believe he was going somewhere in that direction.'

I saw a blue and silver machine-those are his colours, aren't they?'

The German's eyes never left Biggles' face. 'So! you saw him?' he exclaimed.

I've said so, haven't I?' answered Biggles shortly. 'Is there anything particularly funny about that, if he was working in the same area? The heat made visibility bad, but I think it was his machine. I wish he'd keep away from me in the air; if the British see him hanging about without him attacking they may wonder why.'

'Did you have any trouble?'

'Nothing to speak of. But I've got an important report to make, so I can't stay talking now.' So saying, Biggles turned on his heel and walked quickly in the direction of the fort.

There was an odd expression on the Count's face as he looked up from his desk and saw who his visitor was. 'Well, what is it?' he asked irritably.

'The Australian troops are hidden among the palms around Sidi Arish, sir,' stated Biggles, without preamble.

A look of astonishment spread over the Count's face, but it was quickly replaced by another in which grim humour, not unmixed with suspicion, was evident. 'So!' he said, nodding his head slowly. 'So! Where is Hauptmann von Stalhein?'

On the tarmac, sir-or he was a moment ago.' ask him to come here at once. That's all.'

Biggles left the room with the feeling that something had gone wrong, although he could not imagine what it was. Had the Count been pleased with his report, or had he not? He did not know, and the more he thought about it the less was he able to decide. He hurried around the corner of the sheds in search of von Stalhein, and then stepped back quickly as he saw him. For a moment he watched, wondering what he was doing, for he appeared to be working on the Pup's engine.

Biggles heard footsteps approaching, and rather than be found in the act of spying on his superior officer, he stepped out into the open and walked towards von Stalhein, who was now examining something that he held in the palm of his hand, something that he dropped quickly into his pocket when he heard some one coming.

'Will you please report to the Count immediately,' Biggles told him with an a.s.surance he was far from feeling.

'Certainly,' replied the other. 'I shall be glad to see him,' he added, with a suspicion of a sneer, and limped off towards the fort without another word.

Biggles watched him go with mixed feelings.

'What the d.i.c.kens was he up to?' he muttered in a mystified tone, as the German disappeared through the entrance to the fort. He took a swift pace or two to where von Stalhein had been standing. One glance, and he knew what had happened, for there, plain to see in the cowling, was a small round hole that could only have been made by one thing-a bullet. His heart gave an unpleasant lurch as he realised just what it implied, and his teeth came together with a click. 'That cunning devil misses nothing,' he growled savagely. 'He knows now that I've been under fire.' Then, seized by a sudden alarm, he lifted the cowling, and looking underneath, saw what he had feared. In a direct line with the puncture in the cowling there was another jagged hole in the wooden pattern that divided the engine from the c.o.c.kpit. But the hole did not go right through. The bullet must have been stopped by it, in which case it should still be sticking in the stout ash board; but it was not.

'He found it, and he's dug it out with his pen-knife,' thought Biggles, moistening his lips.

'He'll know it's a German bullet,' he went on, thinking swiftly, with his brain trying to grasp the full purport of the new peril. then he gave a sigh of relief as an avenue of escape presented itself. 'It might have been fired some time ago; if he says anything about it I can say that it's always been there-was probably one of he shots fired by the Hun who brought the machine down,' he decided, turning towards the aerodrome buildings, for he did not want von Stalhein to return and see him examining the machine.

For a moment or two he was tempted to turn and jump into the machine and escape to the British lines while he still had an opportunity of doing so, but he fought back the desire, and then started as his eyes fell on two soldiers who had appeared round the corner of the hangars. He noticed that they carried rifles. They stopped when they saw him and leaned carelessly against the side of the hangar. 'Watching me, eh? You'd have shot me too, I expect, if I'd tried to get back into that machine,' he thought banefully. 'Well, now we know where we are, so I might as well go and get some lunch; it looks as if it might be my last.'

He walked unhurriedly to his room, changed, and then strolled into the ante-room of the Mess, where a number of officers were lounging prior to going in to lunch. A word or two of conversation that was going on between a small group at the bar reached his ears, and a cold shiver ran down his spine as he deliberately paused to listen. 'Leffens . late . .

. new bullets . .

were some of the words he heard.

In the ordinary way most of the regular flying officers ignored him, no doubt on account of his a.s.sumed traitorous character-not that this worried him in the least-but one of them, whose name he knew to be Otto Brandt, now detached himself from the group and came towards him.

'Haff you seen Leffens?' he asked, anxiously, in fair English.

Biggles felt all eyes on him as he replied, 'Yes, I saw him this morning, or I thought I did, near Jebel-Tel, but I was not absolutely certain. Why?'

'He ha.s.s not come back. It is tragic-very bad,' replied the German heavily.

'Very bad?' queried Biggles, raising his eyebrows.

;la, very bad-if he has fell. He was making test of the new bullets that came only yesterday. If he has fell in the British trench they will know of our new bullets at once, which is very bad for us.'

'Yes,' said Biggles, vaguely, in a strangled voice, wondering how he managed to speak at all, for his heart seemed to have stopped beating. He walked over to the window and stared out across the dusty aerodrome. 'So Leffens was carrying a new type of bullet,' he breathed, 'and von Stalhein has found one of them in my machine. 'That'll take a bit of explaining. Well, if they'll only give me until to-night I'll blow up their confounded reservoir, and then they can shoot me if they like.'

With these disturbing thoughts running through his head he walked through to the dining-room, had lunch, and then repaired to the aerodrome, observing that the two soldiers still followed him discreetly at a respectful distance. He was just in time to see a two-seater Halberstadt* take off and head towards the lines. Half a dozen Pfalz scouts followed it at once and took station just above and behind it.

'There goes the photographic machine with an escort,' he thought dispa.s.sionately, as they disappeared into the haze. He wondered vaguely what von Stalhein was doing, and how long it would be before he was confronted with Leffen's bullet and accused of double dealing; but then, deciding that it was no use meeting trouble half-way, he turned leisurely towards the pilot's map-room, where he studied the position of the reservoir, which was a well-known landmark. Satisfied that he could find the place in the dark, he returned to his quarters, to plan the recovery of the bomb which he had left on at the aerodrome, and await whatever might befall.

He had not long to wait, Heavy footsteps, accompanied by the unmistakable dragging stride of von Stalhein, sounded in the pa.s.sage. They halted outside the door, which was thrown open. The Count and von Stalhein stood on the threshold.

'May we come in?' inquired von Stalhein, rather unnecessarily, tapping the end of his cigarette with his * German two-seater fighter and ground attack biplane with two machine guns, one synchronised to fire through the propeller for the pilots use.

forefinger to knock off the ash, a curious habit that Biggles had often noticed.

Of course,' he replied quickly. 'There isn't much room, but-'

'That's all right,' went on von Stalhein easily. 'The Chief would like to ask you a question or two.'

I will do my best to answer it, you may be sure,' replied Biggles. Through the window, out of the corner of his eye, he saw the Halberstadt and its escort glide in, but his interest in them was short-lived, for the Count was speaking.

'Brunow, this morning you reported to me that you had located a division of Australian cavalry at Sidi Arish.' It was both a statement and a question.

I did, sir.'

'Why?'

Biggles was genuinely astonished. I'm afraid I don't quite understand what you mean,'

he answered frankly, with a puzzled look from one to the other.

'Then I will make the position clear,' went on the Count, evenly. 'The story I told you of the movement of Australian troops from Egypt was purely imaginary. I merely wished to test your- er- zeal, to find out how you would act in such circ.u.mstances. Now! What was your object in rendering a report which you knew quite well was incorrect?'

'Do you doubt my word, sir?' cried Biggles indignantly. 'I don't understand why you should consider such a course necessary. May I respectfully request, sir, that if you doubt my veracity you might post me to another command where my services would be more welcome than they are here?' He glared at von Stalhein in a manner that left no doubt as to whom he held responsible for the suspicion with which he was regarded.

The Count was obviously taken aback by the outburst. 'Do you still persist, then, that your report is authentic? Surely it would be a remarkable coincidence-'

There was a sharp tap on the door, and Mayer, the Staffel leader of the Halberstadt squadron, entered quickly. 'I'm sorry to interrupt you, sir,' he said briskly, 'but I was told you were here, and I thought you'd better see this without loss of time.' He handed the Count a photograph, still dripping from its fixing bath.

The Count held it on his open hand, and von Stalhein looked down at it over his shoulder.

'Himmel!*" Von Faubourg's mouth opened in comical surprise, while von Stalhein threw a most extraordinary look in Biggles' direction.

'Brunow, see here,' cried the Count. 'But of course, you have seen it before, in reality.'

Biggles moved nearer and looked down at the photograph. It was one of the vertical type, and showed a cl.u.s.ter of white, flat-topped houses upon which several tracks converged. At intervals around the houses were three small lakes, or water-holes, beyond which were extensive groves of palm-trees. But it was not these things that held the attention of those who now studied the picture with practised eyes. Between the palms were long rows of horse-lines and cl.u.s.ters of tiny figures, foreshortened to ant-like dimensions, that could only be men.

The Count sprang to his feet. 'Splendid, Brunow,' he exclaimed, 'and you, too, have done well, Mayer. Come on, von Stalhein, we must attend to this.'

'But - ' began von Stalhein, but the Count cut him short.

* Heavens!

'Come along, man,' he snapped. 'We've no time for anything else now.' With a parting nod to Biggles, he left the room, followed by the others. At the door von Stalhein turned, and leaning upon his sticks, threw another look at Biggles that might have meant anything. For a moment Biggles thought he was going to say something, but he did not, and as the footsteps retreated down the pa.s.sage Biggles sank back in his chair and shook his head slowly.

'This business gives me the heebie-jeebies,' he muttered weakly; 'there's too much head-work in it for me. Well, the sooner I blow up the water-works the better, before my nerve peters out.'

Chapter 6.

More Shocks He remained in his quarters until the sun sank in a blaze of crimson and gold, and the soft purple twilight of the desert enfolded the aerodrome in its mysterious embrace. Quietly and without haste he donned his German uniform and surveyed himself quizzically for a moment in the mirror, well aware that he was about to attempt a deed that might easily involve him in the general destruction; then he crossed to the open window and looked out.

All was quiet. A faint subdued murmur came from the direction of the twinkling lights that marked the position of the village of Zabala; nearer at hand a gramophone was playing a popular waltz tune. There were no other sounds. He went across to the door and opened it, but not a soul was in sight. Wondering if the guard that had been set over him had been withdrawn, he closed the door quietly and returned to the window. For some minutes he stood still, watching the light fade to darkness, and then, feeling that the hush was getting on his nerves, he threw a leg across the window-sill and dropped silently on to the sand.

His first move he knew must be to retrieve the bomb before the moon rose; fortunately it would only be a slim crescent, but even so it would flood the aerodrome with a radiance that would make a person walking on it plainly visible to any one who happened to be looking in that direction. The light of the stars would be, he hoped, sufficient to enable him to find the small box that contained the explosive.

Resolutely, but without undue haste, he reached the tarmac and sauntered to its extremity to make sure no one was watching him before turning off at right angles into the darkness of the open aerodrome. He increased his pace now, although once he stopped to look back and listen; but only a few normal sounds reached him from the spa.r.s.e lights of the aerodrome buildings, and he set about his search in earnest.

In spite of the fact that he had marked the place down very carefully, it took him a quarter of an hour to find the bomb, and he had just picked it up when a slight sound reached him that set his heart racing and caused him to spread-eagle himself flat on the sandy earth. It was the faint c.h.i.n.k of one pebble striking against another.

That pebbles, even in the desert, do not strike against each other without some agency, human or animal, he was well aware, and as far as he knew there were no animals on the aerodrome. So, hardly daring to breathe, he lay as still as death, and waited. Presently the sound came again, nearer this time and then the soft pad of footsteps. He looked round desperately for a hiding-place. A few yards away there was a small wind-scorched camel-thorn bush, one of several that still waged a losing battle for existence on the far side of the aerodrome. As cover it was poor enough and in daylight it would have been useless, but in the dim starlight it was better than nothing, and he slithered towards it like a serpent. As he settled himself behind it facing the direction of the approaching footsteps, a figure loomed up in the darkness on the lip of the depression in which he lay.

It was little more than a silhouette, but as such it stood out clearly, and he breathed a sigh of relief when he saw that it was an Arab in flowing burnous and turban.

But what was an Arab doing on the aerodrome, which had been placed out of bounds for them? The man, whoever he was, was obviously moving with a fixed purpose, for he strode along with a swinging stride; he looked to neither right nor left and soon disappeared into the darkness.

Biggles lay quite still for a good five minutes wondering at the unusual circ.u.mstance.

Had it been his imagination, or had there been something familiar about that lithe figure?

Had it stirred some half-forgotten chord in his memory, or were his taut nerves playing him tricks? But he could not wait to ponder over the strange occurrence indefinitely, so with the bomb in his pocket, he set off swiftly but stealthily towards the distant lights.

He had almost reached them when, with an ear splitting bellow, an aero-engine opened up on the far side of the aerodrome, almost at the very spot where he had just been; it increased quickly in volume as the machine moved towards him, obviously in the act of taking off. In something like a mild panic lest he should be knocked down, he ran the last few yards to the end of the tarmac, and glancing upwards, could just manage to make out the broad wings of an aeroplane disappearing into the starlit sky. For a second or two he watched it, not a little mystified, for it almost looked as if the Arab he had seen had taken off; but deciding that it would be better to leave the matter for further consideration in more comfortable surroundings, he looked about him. No one was about, so holding the bomb close to his side, he hurried back to his quarters. I'd better see how this thing works before tinkering about with it in the dark, otherwise I shall go up instead of the waterworks,' he thought grimly.

He reached his room without incident, and, as far as he could ascertain, without being seen. Placing the bomb in the only easy chair the room possessed, he was brushing the sand from his uniform when a soft footfall made him turn. Count von Faubourg, in pyja-mas and canvas shoes, was standing in the doorway.

Biggles' expression did not change, and he did not so much as glance in the direction of the box lying in the chair. 'h.e.l.lo, sir,' he .said easily. 'Can I do something for you?'

'No, thanks,' replied the Count, stepping into the room. 'I saw your light, so I thought I'd walk across to say that you did a good show this morning. I wasn't able to say much about it this afternoon because von Stalhein-well, he's a good fellow but inclined to be a bit difficult sometimes.'

'That's all right, sir, I quite understand,' smiled Biggles, picking up a cushion from one of the two upright chairs and throwing it carelessly over the box. He pushed the upright chair a little nearer to his Chief. 'Won't you sit down, sir?' he said.

'Thanks,' replied the Count. But to Biggles horror he ignored the chair he had offered and sat down heavily in the armchair. 'h.e.l.lo, what the d.i.c.kens is this?' he went on quickly, as he felt the lump below the cushion.

'Sorry, sir, I must have left my cigarettes there,' apologized Biggles, picking up the box and throwing it lightly on to the chest of drawers. In spite of his self-control he flinched as it struck heavily against the wood.

'What's the matter?' went on the Count, who was watching him. 'You look a bit pale.'

I find the heat rather trying at first,' confessed Biggles. 'Can I get you a drink, sir?'

'No, thanks; I must get back to dress. But I thought I'd just let you know that your work of this morning will not be forgotten; you keep on like that and I'll see that you get the credit for it.'