"Humph! I don't think I can allow that--at any rate, until I have tried it myself."

"You don't mean it, Uncle!"

"Well, having an hour to spare, I think perhaps--I've a very open mind, you know."

"Come _on_, sir!" cried Lawrence, slapping him on the back. "That's sporting, upon my word."

"Don't fly away with me," said Mr. Appleton, as he got into his place.

"One hour: no more."

But when they were soaring northward down the river, and came to where the valley broadened out into the plains of Turkestan, Mr. Appleton forgot altogether about his time limit. The old adventurous spirit was still strong in him; after the first few minutes he was quite at his ease, and even when Bob "banked" the machine in wheeling round, or when a sudden gust swept through a rent in the mountain and made the aeroplane heel over slightly, he showed no nervousness. The flight lasted two hours, and as they walked back along the pathway, Mr.

Appleton said--

"If the country were only flatter, I might be tempted to go in for flying myself. It's most exhilarating. But I'm afraid I'd never be much good at it. I fancy it ought to be learnt young, like golf."

After that both Mr. Appleton and Gur Buksh were occasional pa.s.sengers with the boys. One day, as Lawrence was watching from the compound the flight of Bob accompanied by the Sikh, Ditta Lal came to his side.

"I am consumed with envy, sir," he said: "envy, eldest born of h.e.l.l, as blind poet sings."

"Why, what's wrong?"

"Why, sir, that unlettered Sikh learns secrets of empyrean hidden from me, B.A. of Calcutta University."

"Well, we'll take you, any time you like."

"Alas, sir! I am, through no fault of my own, fat and scant of breath, and rapid transit through rarefied atmosphere would blow me out--I mean, put disastrous strain upon my panting lungs."

"D'you know, Babu, I think you're a funk."

"I repel charge with honest indignation, sir. I am bold as a lion, king of beasts--on terra firma, sir."

They had been using the aeroplane for about a fortnight when a convoy of provisions arrived. The leader of the caravan brought news which gave interesting material for discussion at the supper-table, and which was talked over with scarcely less eagerness among the natives. The man reported that he had had great difficulty in getting through.

Apparently an embargo had been laid on all food stuffs. Armed and mounted men were flocking south-west from all parts of Mongolia, and the talk of the country was that another great movement against Russia was in preparation.

"They'll have a tougher job this time," said Mr. Appleton, in the quiet hour before bedtime. "It was easy enough to lop off one of the extremities of the empire, but they'll find things more difficult as they near the European border, if that's what they are aiming at. I don't know whether you know anything about history----"

"I know Napoleon's campaigns, not much else," said Bob.

"Well, you can take it from me, then, that when the Mongols were at their strongest they couldn't keep a permanent footing in European Russia. But there's such a lot of them, all mounted, too, that there's just a chance they may sweep across the southern plains as their forefathers did. Russia is in a bad way; they know that, of course.

This long war with Germany has broken her credit; she's seething with unrest and rebellion; Finland's in revolt at last, and I shouldn't wonder if the Poles make a move now: they wouldn't before, because they don't love the Germans. It'll be rather curious if the Mongols do cut a slice out of the bloated monster."

A night or two after this, when the caravan had departed, Bob awoke in the small hours, and feeling rather thirsty, got up for a drink. The day had been very hot, and before returning to bed he sat at the open window to inhale the fresh cool breeze that blew along the gorge. Everything was very still. All that he could hear was the gurgling of the stream, now swollen to its full extent by the melted snow from the mountains; and the occasional whinny of a horse from the sheds that served as stables on the other side.

He had sat thus for a few minutes drinking in the beauty of the night when his eye was caught by a faint glow in the distance. It seemed to be near the entrance of the Pathan gallery, his own section of the mine.

The glow flickered; it was not strong enough to light up the surroundings.

"That's very curious," he thought, and was on the point of awaking Lawrence, when it occurred to him that he would look rather foolish if it proved to be nothing but a colony of glow-worms. He knew nothing of natural history, or he would not have suspected the possibility of finding glowworms in such a spot. But he was sufficiently curious to feel that he must find out the cause of the light. He could not leave the house without pa.s.sing through his uncle's room, and unwilling to disturb the household, he made up his mind to climb out of the window, which was at no great distance above the ground. The timbers of the upper part of the house were rough; and a practised climber would find no difficulty in descending by availing himself of their inequalities until he reached the stone part and could drop.

He pulled on his socks, thrust his arms into his smoking jacket, and clambered out. The sound he made in reaching the ground was so faint that it did not disturb the doorkeeper, slumbering Indian fashion on the threshold thirty feet away. Crossing the compound on tiptoe, he came to the fence, and regretted that he had not thought to bring his key of the gate: there was nothing for it but to scale the obstacle. This he did, and crossed the Kalmuck section in the same way, moving very quietly, for he did not wish to attract the attention of the sentry on duty at the drawbridge or to rouse the settlement.

From the time of his dropping from the window until he had crossed the second fence and stood in the Pathan section, the glow had been hidden from him. It now revealed itself as originating in the mine gallery.

The glow was diffused through the opening, though the source of light was not visible. No one had any business there after the bugle had sounded the time for ceasing work. Thinking that perhaps the Pathan foreman, Muhammad Din, had forgotten to extinguish one of the torches that were employed for lighting the miners at their work, Bob was about to cross the ground and enter the gallery without precaution. But he was checked by the thought that the explanation might not be so simple.

He threw a glance round the compound. All was dark and quiet. Then he stole across to the mouth of the gallery, and after a moment's pause entered it.

Some little distance from the entrance a torch was burning in its socket on the wall. n.o.body was in sight. If there was indeed a trespa.s.ser in the mine, he was either behind one of the beams supporting the roof, or farther down the gallery. This was straight from the opening up to the torch, which was so placed as to light a further stretch that bent a little inwards. Bob went along carefully, looking behind every beam and into every recess, but without discovering an intruder.

Having come level with the torch, he stopped, and glancing round the curving wall, was surprised to see another light about twenty paces ahead. It was burning but dimly; the ventilating apparatus was not at work; but the illumination was sufficient to reveal the figure of a man bending to the floor, engaged apparently in gathering small fragments of rock. Bob could not identify the man, whose back was towards him.

Whatever his object was, there was something suspicious in his having chosen the dead of night for carrying it out; and Bob at once made up his mind to steal upon the man, seize him, and haul him before Mr.

Appleton. He crept forward; there were only about a dozen paces between the two. But while he was in the very act of making his leap, he was conscious of a rush of feet behind him. Next moment he was struck by a heavy object, and fell on his face to the floor of the gallery. His head hit the hard rock; there was one instant of intense pain, and then his senses forsook him.

[Ill.u.s.tration: THE ATTACK IN THE GALLERY]

CHAPTER THE SIXTH

NURLA BAI DISAPPEARS

Bob never knew how long he lay unconscious on the floor of the gallery.

When he came to himself he was in darkness: only the smoky atmosphere remained to bear witness to the reality of the torches. He rose dizzily to his feet, feeling sick and giddy as the result both of his blow and of the close air, and groped his way slowly to the entrance. There the cool breeze somewhat revived him; but he found it difficult to make his way past the obstacles which had given him no trouble before. To scale the fences cost much labour, and he was near fainting by the time he reached the house. Having no key with him, he had to waken the darwan who lay wrapped in rugs on his mat before the door. The man was much surprised to see him, but said nothing as he gave him admittance. Bob crept upstairs quietly; his uncle's door was open, and he managed to cross the room without waking him. Then he dropped on to his bed and nudged his brother.

"You're a juggins," said Lawrence rather unfeelingly, when he had heard the story. "That's the sort of thing they do in the school stories, when the bold bad bully climbs down the gutterpipe and sneaks off to the pub to play cards and swill swipes. But I say, you're not hurt, old man?"

"The whack on the head rather crumpled me up," replied Bob.

Lawrence was out of bed in a trice, lit his candle, and bent over his brother.

"There's a b.u.mp as big as a duck's egg," he said. "Jolly lucky your head's hard, old chap! Turn over, and I'll bathe it."

In getting the water-can he stumbled over his boots, making a slight noise.

"It's time you fellows were asleep, came a m.u.f.fled voice through the door. Mr. Appleton had awoke, and fancied that the boys had not yet settled down for the night.

"Shall we tell him?" said Lawrence.

"I meant to wait till morning, but as he's awake--yes, I think we had better."

Lawrence opened his uncle's door.

"I say, Uncle," he said, "Bob fancied he heard burglars and went prowling without a knuckle-duster----"

"Go to bed," growled Mr. Appleton, only half awake.

"It'll keep till morning, but I think you had better hear it now. I'll tell you through the doorway while I bathe Bob's head."

"What's wrong with his head?"