Tibet consists of high table-lands without vegetation, with here and there snowy peaks and barren ravines, torrents fed by glaciers, depressions with glittering beds of salt, lakes surrounded by luxurious forests, with icy winds sweeping over all.

The barometer indicated an altitude of thirteen thousand feet above the level of the sea. At that height the temperature, although it was in the warmest months of the northern hemisphere, was only a little above freezing. This cold, combined with the speed of the "Albatross," made the voyage somewhat trying, and although the friends had warm traveling wraps, they preferred to keep to their cabin.

It need hardly be said that to keep the aeronef in this rarefied atmosphere the suspensory screws had to be driven at extreme speed. But they worked with perfect regularity, and the sound of their wings almost acted as a lullaby.

During this day, appearing from below about the size of a carrier pigeon, she passed over Garlock, a town of western Tibet, the capital of the province of Cari Khorsum.

On the 27th of June, Uncle Prudent and Phil Evans sighted an enormous barrier, broken here and there by several peaks, lost in the snows that bounded the horizon.

Leaning against the fore-cabin, so as to keep their places notwithstanding the speed of the ship, they watched these colossal masses, which seemed to be running away from the aeronef.

"The Himalayas, evidently," said Phil Evans; "and probably Robur is going round their base, so as to pass into India."

"So much the worse," answered Uncle Prudent. "On that immense territory we shall perhaps be able to --"

"Unless he goes round by Burma to the east, or Nepal to the West."

"Anyhow, I defy him to go through them."

"Indeed!" said a voice.

The next day, the 28th of June, the "Albatross" was in front of the huge mass above the province of Zang. On the other side of the chain was the province of Nepal. These ranges block the road into India from the north. The two northern ones, between which the aeronef was gliding like a ship between enormous reefs are the first steps of the Central Asian barrier. The first was the Kuen Lung, the other the Karakorum, bordering the longitudinal valley parallel to the Himalayas, from which the Indus flows to the west and the Brahmapootra to the east.

What a superb orographical system! More than two hundred summits have been measured, seventeen of which exceed twenty-five thousand feet. In front of the "Albatross," at a height of twenty-nine thousand feet, towered Mount Everest. To the right was Dhawalagiri, reaching twenty-six thousand eight hundred feet, and relegated to second place since the measurement of Mount Everest.

Evidently Robur did not intend to go over the top of these peaks; but probably he knew the passes of the Himalayas, among others that of Ibi Ganim, which the brothers Schlagintweit traversed in 1856 at a height of twenty-two thousand feet. And towards it he went.

Several hours of palpitation, becoming quite painful followed; and although the rarefaction of the air was not such as to necessitate recourse being had to the special apparatus for renewing oxygen in the cabins, the cold was excessive.

Robur stood in the bow, his sturdy figure wrapped in a great-coat. He gave the orders, while Tom Turner was at the helm. The engineer kept an attentive watch on his batteries, the acid in which fortunately ran no risk of congelation. The screws, running at the full strength of the current, gave forth a note of intense shrillness in spite of the trifling density of the air. The barometer showed twenty-three thousand feet in altitude.

Magnificent was the grouping of the chaos of mountains! Everywhere were brilliant white summits. There were no lakes, but glaciers descending ten thousand feet towards the base. There was no herbage, only a few phanerogams on the limit of vegetable life. Down on the lower flanks of the range were splendid forests of pines and cedars. Here were none of the gigantic ferns and interminable parasites stretching from tree to tree as in the thickets of the jungle.