The following morning at seven o’clock Douglas rode into the parade ground, and found his men already drawn up, together with the two field-pieces; and half an hour later the little army clattered out of the barrack-yard into the streets, past the plaza, out of the north gate, and swung into the road which led north-eastward toward Lake Titicaca, reaching La Paz four days after leaving Arica. They stayed here one day, leaving on the following morning, and by nightfall the force was at the foot of the mountains which they would have to traverse before reaching Sorata. Here they camped for the night, pushing forward the next day right into the heart of the mountains, which, at this altitude, were clothed with thick pine forests, and cut up by mountain torrents spanned by narrow and frail bridges, across which it was a very difficult and supremely dangerous task to transport the horses and the guns.

They had been among the mountains a week, and were approaching fairly close to Coroico; Jim therefore took the precaution to throw out scouts in all directions round his little force, in order to prevent surprise; and one evening, just before darkness began to settle down, one of the men came riding in to say that he had caught sight of a small body of Bolivians hovering among the hills about a mile to the right of the main body. “Evidently,” thought the young commander, “the guerillas are expecting some such expedition as this, and have thrown out their outposts; there will therefore be little hope of taking them by surprise.” However, as there was no further alarm, and as darkness was fast closing down, orders were given for the camp to be pitched for the night; and very soon the horses were picketed and the men were under canvas, sentries were posted, and everything was made snug and comfortable for the night.

About nine o’clock, feeling greatly fatigued, Jim turned into his tent, and, wrapping himself in his heavy overcoat, threw himself down on the ground, determined to get to sleep early that he might feel fresh and fit for the next morning, when they might reasonably expect to get into touch with the enemy. But try as he might, and tired as he was, sleep refused to visit him, and the harder he tried the wider awake did he become. He also found that he was rapidly becoming obsessed by a horrible feeling that all was not right, that there was some unknown but terrible danger hovering over the sleeping camp. He strove to dispossess his mind of such fancies by assuring himself that sentries were posted everywhere, and that therefore the camp would be early alarmed in the event of an attack being made; but it was all to no purpose; the presentiment only held him the more firmly in its embrace. He had just looked at his watch and discovered that it was midnight, and that he had been tossing and tumbling for three hours, when his ears caught a very faint sound, coming apparently from some distance away.

Douglas sprang to his feet in a moment, and striding to the flap of his tent, bent all his energies to the task of listening intently. Yes, there it was again! It was coming from the direction of a wooden suspension bridge which spanned a broad ravine, and which the force had crossed about a quarter of an hour before camping down; and it took the form of heavy, muffled blows of iron against wood.

“Hallo!” exclaimed Douglas, “there is something wrong here! but what are the sentries doing?”

In a second he had belted on his sword and revolver, and plunged out of the tent in the direction from which the sound was coming, and a few minutes later arrived at the place where the sentry should have been standing; but there was no sign of the man—he was nowhere to be seen.

Caramba!” exclaimed Jim, “I believe there has been foul play here!” and he began to hunt about among the undergrowth for some sign of the missing man. The next moment he stumbled over something soft, and fell upon his knees, putting out his hands to save himself. They came in contact with a rough overcoat, and in an instant Jim knew it for that of the sentry. Somewhat incautiously Jim struck a match, and saw at once what had happened to the poor fellow; he had been murdered by having a dagger driven between his shoulders!

“By Jove!” gasped the Englishman, “there has been foul treachery here. Aha!” he continued, starting to his feet, “what is that?”

His exclamation was occasioned by a sudden booming crash coming from the direction of the suspension bridge over which his force had passed before camping, and, with a sense of imminent disaster clutching at his heart, he dashed forward in the direction of the chasm, leaving the sentry to the tender mercies of the vultures. Jim came in sight of the bridge—or, rather, its remains—a few seconds later, and saw at once what had happened. The dull, chopping noise which had first attracted his attention had been caused by axe-strokes, and the bridge had been cut through from the farther side, allowing it to fall into the ravine. In a moment the significance of the occurrence flashed into Douglas’s mind. What if the place whereon they were camped should prove to be a sort of island between the ravines? And suppose the farther bridge, their only way of escape, should also have been destroyed?

Like a hare Jim doubled on his tracks and fled back to the camp, which he found already alarmed by the noise of the falling bridge, and a few seconds sufficed to warn the men of what had occurred, and to arouse in them a sense of imminent peril. Horses were saddled, bugles rang out, tents were struck, the guns limbered up, and in ten minutes the force was dashing along at top speed toward the next bridge, which they now realised could not be very far away.