For exact measurements we depended on Topographer Hendriksen, who was due to triangulate Coropuna in the course of his survey along the 73d meridian. My chief excuse for going up the mountain was to erect a signal at or near the top which Hendriksen could use as a station in order to make his triangulation more exact. My real object, it must be confessed, was to enjoy the satisfaction, which all Alpinists feel, of conquering a "virgin peak." CHAPTER II Climbing Coropuna The desert plateau above Chuquibamba is nearly 2500 feet higher than the town, and it was nine o'clock on the morning of October 10th before we got out of the valley. Thereafter Coropuna was always in sight, and as we slowly approached it we studied it with care. The plateau has an elevation of over 15,000 feet, yet the mountain stood out conspicuously above it. Coropuna is really a range about twenty miles long. Its gigantic massif was covered with snow fields from one end to the other. So deep did the fresh snow lie that it was generally impossible to see where snow fields ended and glaciers began. We could see that of the five well-defined peaks the middle one was probably the lowest. The two next highest are at the right, or eastern, end of the massif. The culminating truncated dome at the western end, with its smooth, uneroded sides, apparently belonged to a later volcanic period than the rest of the mountain. It seemed to be the highest peak of all. To reach it did not appear to be difficult. Rock-covered slopes ran directly up to the snow. Snow fields, without many rock-falls, appeared to culminate in a saddle at the base of the great snowy dome. The eastern slope of the dome itself offered an unbroken, if steep, path to the top. If we could once reach the snow line, it looked as though, with the aid of ice-creepers or snowshoes, we could climb the mountain without serious trouble. ------ FIGURE Mt. Coropuna from the South ------