Several condors were wheeling in the air above the little party, but, besides these huge birds of the mountains, there were no visible signs of animal life. In the last half-hour of the ascent Frank had felt the effect of the rarefied atmosphere of his great elevation. He breathed with difficulty, and as he took the air into his lungs its lightness was very unsatisfying. There seemed to be a heavy pressure upon his chest, and several times a faintness came over him which threatened to end in unconsciousness. He tried to think of other things, and in this way preserved his senses, and kept from falling out of the saddle. But if the youth suffered from the rarity of the atmosphere while making no exertions, what must it have been with the animal he rode? The breath of the mule came quick and fast, and was expelled from the nostrils with a loud sound; the animal could hardly take a dozen steps without halting to rest; and it was the same with all the other beasts of the train. Frank declared afterwards that he never witnessed a more notable instance of patience and perseverance on the part of the much-derided hybrid than in that ride over the Andes. He forgave the animal for his eccentricities and insubordination near Mendoza, and promised never again to despise a mule. Before beginning the descent it was necessary to make a careful adjustment of the saddles, to prevent their slipping forward, as the road is quite as steep as the one up which they had just been climbing. Every strap was tightened and fastened, and when all was ready, and the mules had fully recovered their breathing powers, the column began its march into Chili. "Down, down we went," wrote Frank in his journal, "along a series of zigzags cut into the steep slope of the mountain at an angle of nearly forty-five degrees. The vast area before us, bordered by the distant ocean, was broken into mountains and valleys, dotted with forests and stretches of open country, sprinkled with towns and villages, and seamed and streaked with the tortuous paths of rivers which have their sources on the sides of the Andes, and are fed from the melting snows. The contemplation of such an expanse of the world's surface lying at my feet told more plainly than my sufferings with the rarefied air the great elevation I had attained. I was at a height of more than two miles, and the summits of mountains that would be considered lofty almost anywhere else were far below me. The ocean seemed near and far; its horizon appeared at an almost limitless distance, and at the same time I could half believe that a stone thrown from my hand would fall on the shore. "We halted at the first hut, and remained an hour for lunch and rest. While we were waiting, Federico told me how he was once caught at this very casucha in a _temporale_, or snow-storm.