Glenarvan never lost sight of young Robert, for his age and vivacity made him imprudent. Paganel was a true Frenchman in his impetuous ardor, and hurried furiously along. The Major, on the contrary, only went as quick as was necessary, neither more nor less, climbing without the least apparent exertion. Perhaps he hardly knew, indeed, that he was climbing at all, or perhaps he fancied he was descending.

The whole aspect of the region had now completely changed. Huge blocks of glittering ice, of a bluish tint on some of the declivities, stood up on all sides, reflecting the early light of morn. The ascent became very perilous. They were obliged to reconnoiter carefully before making a single step, on account of the crevasses. Wilson took the lead, and tried the ground with his feet. His companions followed exactly in his footprints, lowering their voices to a whisper, as the least sound would disturb the currents of air, and might cause the fall of the masses of snow suspended in the air seven or eight hundred feet above their heads.

They had come now to the region of shrubs and bushes, which, higher still, gave place to grasses and cacti. At 11,000 feet all trace of vegetation had disappeared. They had only stopped once, to rest and snatch a hurried meal to

V. IV Verne recruit their strength. With superhuman courage, the ascent was then resumed amid increasing dangers and difficulties. They were forced to bestride sharp peaks and leap over chasms so deep that they did not dare to look down them. In many places wooden crosses marked the scene of some great catastrophes.

About two o'clock they came to an immense barren plain, without a sign of vegetation. The air was dry and the sky unclouded blue. At this elevation rain is unknown, and vapors only condense into snow or hail. Here and there peaks of porphyry or basalt pierced through the white winding-sheet like the bones of a skeleton; and at intervals fragments of quartz or gneiss, loosened by the action of the air, fell down with a faint, dull sound, which in a denser atmosphere would have been almost imperceptible.

However, in spite of their courage, the strength of the little band was giving way. Glenarvan regretted they had gone so far into the interior of the mountain when he saw how exhausted his men had become. Young Robert held out manfully, but he could not go much farther.

At three o'clock Glenarvan stopped and said:

"We must rest."

He knew if he did not himself propose it, no one else would.

"Rest?" rejoined Paganel; "we have no place of shelter."

"It is absolutely necessary, however, if it were only for Robert."

"No, no," said the courageous lad; "I can still walk; don't stop."

"You shall be carried, my boy; but we must get to the other side of the Cordilleras, cost what it may. There we may perhaps find some hut to cover us. All I ask is a two hours' longer march."

"Are you all of the same opinion?" said Glenarvan.

"Yes," was the unanimous reply: and Mulrady added, "I'll carry the boy."

The march eastward was forthwith resumed. They had a frightful height to climb yet to gain the topmost peaks. The rarefaction of the atmosphere produced that painful oppression known by the name of PUNA. Drops of blood stood on the gums and lips, and respiration became hurried and difficult. However strong the will of these brave men might be, the time came at last when their physical powers failed, and vertigo, that terrible malady in the mountains, destroyed not only their bodily strength but their moral energy. Falls became frequent, and those who fell could not rise again, but dragged themselves along on their knees.

But just as exhaustion was about to make short work of any further ascent, and Glenarvan's heart began to sink as he thought of the snow lying far as the eye could reach, and of the intense cold, and saw the shadow of night fast overspreading the desolate peaks, and knew they had not a roof to shelter them, suddenly the Major stopped and said, in a calm voice, "A hut!"

CHAPTER XIII A SUDDEN DESCENT

ANYONE else but McNabbs might have passed the hut a hundred times, and gone all round it, and even over it without suspecting its existence. It was covered with snow, and scarcely distinguishable from the surrounding rocks; but Wilson and Mulrady succeeded in digging it out and clearing the opening after half an hour's hard work, to the great joy of the whole party, who eagerly took possession of it.