When Lawrence explained how Bob had seen a glow from the window, in the Pathan section of the mine, Mr. Appleton sat up, now thoroughly awakened. He listened to the rest of the story in silence. At its conclusion he said:

"Just cut downstairs and tell that fellow at the door to hold his tongue about it. Why on earth didn't you wake me at once, Bob, instead of playing that schoolboy trick?"

"I didn't want to disturb you."

"That's all very well, though you wouldn't have hurt an old campaigner like me. You ought to have told me at once, and then we might have caught the rascal. I'm afraid there's trouble ahead, and I've a shrewd suspicion who's at the bottom of it. You didn't recognize the man in the gallery?"

"No; his back was towards me."

"What's it mean, Uncle?" asked Lawrence, returning.

"It means that some one--Nurla Bai, I fancy--suspects that I've found silver, or at any rate something better than copper. You remember how he'd been trespa.s.sing on the night you came. But how did he get across?

You saw all the men off the premises at bugle call, Bob?"

"Yes."

"Then he's either in league with the sentry, or caught him napping, though I don't understand how Gur Buksh and his men could have slept through the groaning and creaking of the drawbridge."

"Perhaps it wasn't Nurla at all, but some one on this side," suggested Lawrence.

"I don't believe it for a moment. The Sikhs are perfectly trustworthy; the servants too; and the Babu, though as inquisitive as a monkey, is quite honest and knows nothing about ores--though I daresay he wouldn't own it. Look here! we must say nothing whatever about this matter. To refer to it publicly would only stir up unrest among the workmen, and might lead to disturbances between the Pathans and the Kalmucks. Each set would accuse the other. We must keep quiet for a day or two, and watch. You had better not show up to-morrow, Bob. To see you with your head bandaged would set every one talking."

"I shall be all right in the morning," said Bob.

"I hope so. By the way, you were struck from behind, you say?"

"Yes: there are evidently two men in it."

"So much the better. There'll be two quaking in their shoes, and we may be able to spot signs of guilt in their manner. Keep your eye on Nurla and Black Jack, who follows him like a shadow. You made the darwan understand he's not to talk, Lawrence?"

"He won't say a word, I'm sure."

"Then get to bed. I see you've bandaged Bob's head in a workmanlike way. Where did you learn that?"

"Ambulance work in the school cadet corps, Uncle."

"Ah! They manage things better than when I was young. Good-night, boys."

Bob found himself much better in the morning, and declined his uncle's suggestion that he should remain in bed. But his wound was too painful to allow of his wearing a hat, and his appearance bareheaded, and with a strip of sticking plaster on his neck just behind his ear, caused many curious eyes to be turned towards him. Only the Babu made any reference to it. Inquisitiveness was his failing, and he could never keep his tongue still.

"I perceive, sir," he said, "that you are not in your usual salubrity.

Your countenance is pale, and I opine from patch upon your neck that all is not O.K. Pardon me, have you abraded the cuticle?"

Bob looked at him.

"Because, sir," the Babu continued with great deference, "I have in my store sticky plaster, powdered alum, gold-beater's skin, sweet olive oil, cold cream scented with roses, all things warranted to make epidermis blooming and good as new. Item and in addition, perhaps a little cooling draught may reduce inflammability and----"

"Oh, shut up!" said Bob, and the Babu went away smiling but sorrowful.

The three Englishmen went about their usual occupations as if nothing had occurred. They watched the workmen narrowly for signs of guilt, but could detect nothing. The Pathans were frankly curious and sympathetic; the faces of the Kalmucks were as expressionless as they always appear to Europeans. Nurla Bai, who was the special object of Mr. Appleton's attention, was inscrutable: there was no change in his demeanour.

Convinced that his a.s.sailant had in some way crossed the river in the darkness of the previous night, Bob was at a loss to guess how he had accomplished the feat. In the interval at mid-day, when the men had trooped across the drawbridge for their meal, he suggested to Lawrence that they should walk along the pathway to the ledge on which they kept the aeroplane, and see if there were some fordable place which had escaped their uncle's notice. On the way they examined every foot of the cliff below them. It rose sheer from the bed of the river, so steep and smooth as to afford no foothold for man or beast. Even if the river had been swum or forded, it would have been impossible for any one to climb up to the level platform on which the mine works were situated.

Nor could the most hardy and adventurous stranger have approached from above, for the slope was too steep to give foothold to a mountain sheep.

In the other direction, down-stream, access was equally impossible, and for a time both the boys felt thoroughly baffled.

At length, however, Lawrence made a discovery. In retracing his steps towards the plank pathway he climbed out upon a huge b.u.t.tress of rock that projected some feet into the river.

"Take care!" cried Bob, feeling some alarm at the risk his brother was running.

"All right, old man," returned Lawrence. "It's rather a fine view down the gorge from here. You'd better try it yourself when your head's mended."

He picked his way carefully over the somewhat uneven rock, and had gone three parts of the way round its circ.u.mference when he suddenly stood fixed, staring at something in front and a little below him.

"By George!" he e.j.a.c.u.l.a.t.ed in an undertone. Then he lay flat on the summit of the rock, wriggled forward to the edge, until his head projected, and peered downwards.

"What is it?" asked Bob from his position several yards in the rear.

Lawrence did not answer until he had crawled backward and once more stood erect.

"I've solved the puzzle," he said. "The fellows have got courage at any rate, and must be as agile as monkeys. There's a rope hanging down from the last beam,--down the cliff into the water."

"A rope!"

"Yes, one of our stoutest, cleverly stained so that it's hardly distinguishable from the rock itself. I caught sight of something swaying, and it took me a few seconds to be sure what it was. Whoever it was that knocked you on the head--Tchigin very likely--he must have climbed the rope, twisted himself up on to the planks, and so got to the mine. It's a trick I shouldn't care to attempt."

"But how on earth did he get to the rope from the other side? He couldn't have forded, and the strongest swimmer couldn't get across with the torrent rushing down at something like eight miles an hour."

"That wants thinking out. Meanwhile we'd better get back. If we were seen here we might put somebody on the alert."

"Yes. I tell you what: we'll cross the bridge and stroll up the other side; perhaps we may get a clue there."

They walked back without hurry along the planks, spent some little time in their respective sections of the mine, and then, taking their shot guns, crossed the bridge and walked up the narrow road as they had done many times before when shooting.

"I've been trying to work it out," said Bob as they went. "If I wanted to make for a particular spot on the other side, I should plunge in a good way higher up--you know, where the stream widens and isn't quite so swift. Then I should strike diagonally across and trust the current to carry me where I wanted to go."

"It would sweep you past. You couldn't be sure of hitting the rope."

"I don't know. We'll see when we get opposite it."

They sauntered on side by side, giving no signs of the carefulness with which they were examining the base of the cliff on the farther side. The bank beneath the road on which they were walking was not precipitous like the opposite cliff. Here and there the rocks shelved down to the water's edge, but there was no continuous perpendicular barrier.

Their course brought them presently opposite the b.u.t.tress by which hung the rope. They did not pause, but as they strolled on Bob said--

"You see that in the angle formed by that b.u.t.tress and the cliff there's a sort of backwater: not exactly a backwater, of course, but the force of the current is much diminished there. If a swimmer got to that point, he could make headway against the stream."

"That's just where the rope hangs. Did you see it?"

"No; I only took a pa.s.sing glimpse. We'll turn in a few minutes and take a better look going back."