But there was considerable danger of encountering gusts and eddies sweeping through clefts and gorges here and there, and it was impossible to calculate at what precise angle the aeroplane might be struck by a sudden blast. However, the conditions were no worse than they had already been in some of his practice trips, and he only felt a little additional nervousness because Mr. Appleton had never yet accompanied him except in absolutely calm weather.

Just as they were preparing to start it occurred to Mr. Appleton that some unforeseen contingency might prolong their absence from the mine.

"Run back," he said to Lawrence, "and tell some of the men to bring over enough food for a couple of days and two or three skins of water, in case we don't get a chance to draw some from the river. You had better tell the Pathans, too, to take food in their saddle-bags. It's just as well to be prepared for emergencies."

All arrangements having been made, they took their places. Chunda Beg and the Babu were among the men who had walked to the ledge to witness and a.s.sist in the start.

"I wish good luck and safe return," said the Babu impressively. "As for that villain of deepest dye, I approve of strongest measures. There is varied choice of punishments--pistol, rope, et cetera: the best, in my humble opinion, is to let him dangle from rope until death comes as merciless release."

"If you don't skip, Babu," said Bob, "you'll be caught by our wings, and either be carried up to the heavens or dashed over the edge into the river."

Ditta Lal instantly picked up his skirts and fled, not halting until he reached a safe distance. There he watched the ascent of the aeroplane until it disappeared round a bend in the gorge. Then he returned to the compound, following Chunda Beg, to whose back he discoursed on the velocity of the wind, the native iniquity of the Kalmuck race, and the various tortures to which Nurla Bai might conscientiously be put when he was captured.

Bob steered the machine along the middle of the valley, keeping low in order to avoid the wind. On either side rose the lofty mountain barrier, here overhanging the river, there receding; at some spots an almost perpendicular wall, at others broken into peaks and parapets, with deep hollows in which a scanty vegetation struggled for existence on a thin soil. Now the valley narrowed so that there seemed barely s.p.a.ce for the aeroplane to pa.s.s: now it widened into a series of rocky terraces, seamed by fissures in every direction. The track on the right bank followed the winding course of the river for many miles, then dipped to a ford and reappeared on the left. Some miles farther on it recrossed the river by a crazy bridge of rope, and continued along the right bank past the foothills and out into an extensive plateau.

Bob as usual acted as pilot. By flying pretty close upon the river he not only avoided danger from gusts, but enabled his companions to keep a sharp observation upon the ground. Here and there, where this wound behind the rocks between the bank and the hillside, he left the river, planed a little higher, and steered a course exactly over the track.

The recent invention of planes which could be lengthened or shortened at will rendered it possible to travel at more varied speed than had formerly been the case, and when he was several miles from the mine he reduced speed to the minimum. Even then, however, the aeroplane moved so swiftly that there was some danger of the watchers pa.s.sing their quarry without perceiving them. This was not likely where the track was closely hemmed in between river and hillside. The risk was greatest where the latter receded from the course of the stream, leaving large areas of rough country, sometimes covered with bush, in which the fugitives could without much difficulty hide out of sight of any one not pa.s.sing immediately above them.

The ford at which the track crossed the river was about twenty miles from the mine. Coming to that point without having seen the fugitives, Bob followed the track along the left bank. Here the open s.p.a.ces became more frequent, and it would have been impossible to examine the ground thoroughly without circling. For the present Bob hesitated to do this, feeling that it was more important to keep to the track for so long a distance as the fugitives might have covered had they started at the earliest likely moment, twelve hours before. Another twelve miles brought him to the rope bridge, where he again crossed the river, and so continued until, ten miles farther, the foothills were reached, and the country began to open out.

It was obvious to all three occupants of the aeroplane that the only means of thoroughly searching the comparatively open country at which they had now arrived was to rise to a greater height and sail about in widening circles. Bob therefore adjusted his elevator; and as the machine swept round, the other two peered over on opposite sides, using their gla.s.ses to scan the ground beneath. The fugitives being presumably mounted on the stolen ponies could hardly be otherwise than conspicuous; and when, after more than half an hour's careful observation, nothing had been seen of them, the pursuers came to the conclusion that the men could not yet have quitted the valley. This was a very reasonable inference, considering that they had covered in less than an hour a distance of nearly fifty miles, which the fugitives, even on horseback, must take many hours to traverse. The natural conclusion was that the hors.e.m.e.n, warned by the whirring of the propeller, if not by the actual sight of the aeroplane, had taken shelter in one of the more rugged or more thickly wooded places until the pursuers had pa.s.sed.

There was nothing for it but to turn back and hunt up the valley again.

The aeroplane was crossing the plateau obliquely towards the opening of the gorge when Lawrence suddenly caught sight of a number of round objects resembling bee-hives, cl.u.s.tered in a secluded dell. He pointed them out to Mr. Appleton, who examined them through his gla.s.s.

"They are akois," he said: "the portable huts used by the nomad tribes in these parts, made of a circular wooden framework covered with felt.

But I've never before seen so many in a group."

As they looked, the intervals between the akois became filled with a dense crowd of men, who stood gazing up in astonishment at the strange machine flying high above their heads. The airmen had no particular interest in wheeling about to make a careful inspection of the camp, for it was inconceivable that Nurla and his man had come so far and joined their compatriots, if such these people were. They had soon left it far behind, and descending gradually as they neared the gorge, they re-entered this at an alt.i.tude of not more than a hundred feet above the river to renew their search.

Bob found it by no means easy to follow a course that would enable his pa.s.sengers to obtain a clear view of the more rugged portions of the valley. Here and there, at the wider parts, he was able to wheel round and cover wide areas; but in the narrow stretches he was forced to fly straight ahead without the possibility of turning, unless he should rise to a great height. This would involve a loss of time which could be ill afforded. Once or twice, in attempting to circle, he almost shaved the rocky sides; and deciding that such attempts were too dangerous, he concluded that he had better leave certain parts imperfectly explored rather than risk injury to the aeroplane. He compromised matters by steering a serpentine course, thus covering as much as possible of the ground on both sides of the river.

The aeroplane was approaching the rope bridge when Mr. Appleton suddenly called out that he saw two men on horseback on the track beyond. In another moment he recognized them through his gla.s.s as the men of whom they were in pursuit. They were nearly a mile distant, entering a stretch of the gorge that was particularly rugged, and no doubt afforded plenty of cover. It had been prearranged that as soon as the men were sighted Bob should make a descent as near as possible ahead of them--that is, down-stream--but it was no surprise to Bob--indeed, it was only according to the ill-luck that seems to rule on such occasions--that no suitable landing place offered itself.

He remembered, however, that in flying downstream he had noticed, two or three miles above the bridge, a place where the valley widened sufficiently to allow the aeroplane to circle. He decided to fly direct to this spot, turn, follow the men, outstrip them, and land at a spot some distance down-stream, where a landing had seemed feasible.

Lawrence suggested that he or his uncle should take a flying shot at the men as they pa.s.sed above them, but Mr. Appleton would not consent.

"Punishment before trial won't do," he said.

By this time the fugitives had disappeared behind a sort of parapet of rock just above the bridge, which spanned the river at a height of twenty or thirty feet. On first sighting them, Bob had caused the aeroplane to descend until it was almost level with the bridge. As they came to it, Mr. Appleton rose in his seat behind the pilot, to see, if he could, the precise spot in which the fugitives had concealed themselves. He had just done so, and was leaning slightly to the right, when there came in rapid succession the crack, crack of two rifles. And then Lawrence, in the third seat, was horrified to see his uncle pitch forward, lose his grip on the stay he was clutching, and fall headlong into the river. It all happened so instantaneously that the boy had no time even to reach forward. He sprang up, almost over-balancing himself, but before he could stretch out his hand Mr. Appleton was whirling in mid-air.

At the moment of the accident Bob was made aware that something had happened by the lurch which the sudden loss of weight caused the aeroplane to give. A cry from Lawrence apprised him of the nature of the accident. For a few moments both the boys were dazed by the shock of their uncle's disappearance, so sudden, so unexpected, so terrifying.

Bob had instinctively moved his controlling lever to counter-act the lurch. As soon as he knew what had happened, instinct again prompted him to bring the aeroplane round; but reason coming to his aid, he corrected the movement just in time to avoid dashing the plane against the rocky barrier on his left hand.

"Keep straight ahead!" shouted Lawrence in terror.

But before the words were out of his mouth the danger of a fatal smash was avoided. The aeroplane flew at full speed up-stream. In a few minutes it would reach the wider s.p.a.ce where turning was possible. Only then could the direction of its flight be reversed, and the fate of Mr.

Appleton be ascertained.

In their anxiety for their uncle, both the boys had now forgotten the very existence of the Kalmuck miscreants. It did not occur to them that in repa.s.sing the same spot on their flight down-stream they might be in danger from the same concealed marksmen. As the aeroplane turned, Lawrence called to his brother to descend still lower, so that they might the more easily see their uncle's body if he were still floating in the stream.

"If I see him, I'll dive in," he said. "You go on, land where you can, and come back to my help."

With his eyes fixed on the water below he was unconscious of anything but the swirling flood, and the intense strain of searching the surface as the aeroplane flashed by. Neither Bob nor Lawrence noticed the movements of the two Kalmucks. They, as soon as they had fired their shots, vaulted into the saddles of the horses that stood beneath a tall rock, and dashed at headlong speed along the track towards the bridge.

The horses, urged by their riders, and terrified by the increasing sound of the aeroplane rushing swiftly behind them, took the bits in their teeth and galloped on, completely beyond control. They wheeled on to the bridge. At this moment the aeroplane was only about two hundred yards behind them, and Bob was intending to pa.s.s under the bridge. But the weight of the horses was too much for the frail and clumsy structure. It broke in the middle, and horses and riders plunged into the river. Bob had just time to move his elevator and skim over the confused ma.s.s of bridge, horses and men.

Only for a moment was Lawrence's attention diverted from his quest.

Hitherto he had fixed his eyes from a rapidly diminishing distance upon the spot where his uncle had fallen, and the river beyond. Now he had pa.s.sed the spot itself, and in a few seconds covered the whole distance down which, even allowing for the speed of the current, the body could have been carried. There was no sign of it, and Lawrence felt with horror and despair that the shot had been only too well aimed--that Mr.

Appleton had been killed outright, or so grievously wounded as to be unable to keep himself afloat. He could not endure the suspense and uncertainty.

"I am going in," he cried. "Come back for me."

To make a clean dive from the narrow seat of an aeroplane flying at the rate of thirty miles an hour was impossible. It was a dangerous feat to attempt at all, but Lawrence did not think of that. He fell rather than plunged, at the imminent risk of striking a half-submerged rock in mid-stream. The shock of hitting the water after a haphazard fall of thirty feet was so great that for a time, even after he had risen to the surface, he was too much dazed to be able to distinguish his surroundings. With the instinct of a practised swimmer he trod water until his senses returned to him. Then he saw that he was far below the ruined bridge, and being rapidly carried down-stream. The aeroplane was out of sight. Neither man nor beast was visible on either bank. The Kalmucks must have clambered up the bank and taken to flight. He realized that if his uncle was still in the river he must have overtaken him before the dive was made. It was necessary to husband his strength, and either try to swim against the stream, or make his way to some rock on one side or the other, whence he could watch the current as it flowed past him.

He turned, and for some time breasted the stream until he descried a rocky shelf at the base of the right bank which would prove at once a resting place and a convenient watch post. Nearly exhausted, he dragged himself on to it, and crouched there, intent upon every billow and eddy of the swollen river. Fed by the mountain snows, it flowed on with turbulent tide. The water was bitterly cold, and Lawrence shivered as he waited there minute after minute, hoping, yet dreading, to see his uncle's form rolling past.

Presently he heard the hum of the returning aeroplane. Bob shouted as he sped by, but what he said was indistinguishable. Lawrence felt more and more despairing until with a gleam of hope he wondered whether his uncle had swum to one bank or the other and climbed to safety. He looked at the bank behind him. It was steep, almost perpendicular, but marked by fissures that promised to give him foothold. With teeth chattering and limbs trembling with cold he essayed to clamber up. At another time he would have found the feat easy enough: now he was amazed at the tax it put upon him. Every now and then he stopped, clung on with his hands, and turned his head to glance again at the stream. At last, on gaining the top, he looked along the track in both directions. n.o.body was in sight. The aeroplane had again disappeared from view.

Hesitating a moment he began to walk up the track. A new fear a.s.sailed him: what if the aeroplane had met with an accident! What if the engine had failed, or the pilot had been too venturesome, and in attempting to wheel in too narrow a s.p.a.ce had crashed against the rock! Shivering as much from anxiety as from cold, he felt a glow of extravagant delight when he heard a cheery shout, and Bob came hasting towards him from round the corner of a jutting rock.

"Any sign of him?" asked Bob anxiously as he met his brother.

"No. What can have become of him?"

"I fear the worst: but even if--if he is drowned he must come up some time. We had better walk up and down for a bit."

"Where's the machine?"

"A few yards above the bridge. It was a risky thing, coming down there, but I thought I'd venture, and luckily didn't come to grief."

"Let us get our field-gla.s.ses. We can then examine every crevice in the other bank. We can't get to the other side and examine this. By the way, how did you get across?"

"One of the ropes that formed the hand-rails of the bridge is uninjured.

It sags a bit, but it's just taut enough to swing over by."

For some time they marched up and down, above and below the spot where their uncle had fallen. Bob stripped to his shirt, and swam along with the current below the track, searching every cranny into which he thought the body might have been carried. No discovery rewarded his care except a primitive fishing net, the meshes of which had caught upon the jagged edges of a rock.

"Do you think the Kalmucks got hold of him?" said Lawrence when they again met.

"Upon my word, I had almost forgotten them. They may have done so.

It's clear that they got out of the river, and their horses, too. I didn't see them as I flew up. What more can we do?"

"I don't know. I'm dead beat. I can't help thinking that the Kalmucks must have captured him, alive or dead. When we have rested we had better get our rifles and go and meet the Pathans. They ought to be near by this time. With them hunting on horseback and ourselves in the aeroplane we can scour the country. But we must tell our men; it's no good starting without them."

"I think you're right. We'll get something to eat, and by the time you've had a rest, no doubt the men will arrive."

CHAPTER THE EIGHTH