"Not long after our arrival a train of twenty mules came in from the westward and camped close to us. The drivers fraternized with our men and joined them at supper, and there was a general exchange of information concerning the condition of the roads. There is universal hospitality among the arrieros, and when one party meets another there is an immediate proffer of food, cigarettes, or anything else that may possibly be wanted. Every time we met a train the arrieros would stop to chat a few moments, and then, with an '_Adios!_' and a graceful wave of the hand, hurried on to overtake their charges. "Soon after starting the next morning we passed 'The Inca's Bridge,' a natural causeway over a stream which flows about forty feet below it. The bridge is sixty feet long and averages about the same in width; and Mr. Darwin thinks it was formed by the river breaking through underneath. Lieutenant Macrae, of the United States Navy, made a careful examination, and thinks it was formed by the concretion of the water from several calcareous springs in the hillside, which went on forming shelf after shelf till they reached across. On a shelf under the bridge there are two warm springs which have been hollowed out into baths. I tried the temperature, and found it 97° Fahrenheit; I wanted to take a bath in one of the springs, but was fearful of catching cold after immersion in the warm water. [Illustration: DEEP CHASM IN THE MOUNTAINS.] "The arrieros do not wash their hands or faces from the beginning to the end of a journey; I had been strongly advised to follow their example, and was warned that I would suffer if I did otherwise. I dipped my hands in the warm water, and then yielded to the temptation to wash them; I was paid for my rashness by one of the worst cases of chapped hands I ever experienced. I retained the impurity of my face, and on reaching Santa Rosa my complexion was darker than that of any of my peons, and soiled enough for a street gamin of New York. "From the Inca's Bridge we ascended the valley of the Cuevos River for some distance, and then began a steep ascent. It was a steady struggle, and as we rose higher and higher I could see it was very trying to the strength of our mules. They panted for breath, and after a few minutes' exertion it was necessary for them to take a rest of nearly equal length. At Mendoza, and also in the lower country and on the table-land, I had observed that the arrieros and peons were very cruel to their animals, belaboring them severely for their insubordination, and calling them a great many hard names. But in the dangerous parts of the journey the whole state of affairs was changed. The mules were docile, and quite the reverse of obstinate, while the drivers were models of gentleness. They used neither whip nor spur, but spoke softly, and permitted the animals to suit themselves in going on or resting. For a good deal of the way our advance was very slow.