APPENDIX A 317 



The occupation of these high stations necessitated a great deal of 

 climbing, donbly hard in this rarefied air, and often on volcanoes with a 

 surface consisting of bowlders and ash and in the face of violent hailstorms 

 that made extremely difficult the task of connecting up observations at 

 successive stations. 



At Cotahuasi a new pack-train was organized, and on October 25th I 

 ventured to return alone to the high altitudes in order to continue the 

 topography at the station at 17,633 feet on the summit of the Maritime 

 Cordillera. Dr. Erving was obliged to leave on October 18th and Professor 

 Bowman left a week later in order to carry out his plans for a physi- 

 ographic study of the coast between Camana and Mollendo. Philippi 

 Angulo, a native of Taurisma, a town above Cotahuasi, acted as major- 

 domo on this journey. Knowing the trail and the camp sites, I was able 

 to pick out the stations ahead myself, and made good progress, returning 

 to Cotahuasi on October 29th, three or four days earlier than planned. 

 From Cotahuasi to the coast I had the assistance of Mr. Watkins. The most 

 trying part of the last section of high altitude country was the great 

 Pampa Colorada, crowned by the snow-capped peaks of Solimana and 

 Coropuna, reaching heights of 20,730 and 21,703 feet respectively. The 

 passing of this pampa took seven days and we arrived at Chuquibamba on 

 November 9th. Two circumstances made the work on this stretch 

 peculiarly difficult — the scarcity of camping places and the high tempera- 

 ture in the middle of the day, which heated the rarefied air to a degree 

 that made long-distance shots very strenuous work for the eyes. Although 

 our base signals were stone piles higher than a man, I was often forced to 

 keep my eye to the telescope for hours to catch a glimpse of the signals; 

 lack of time did not allow me to stop the telescope work in the hottest part 

 of the day. 



The top of Coropuna was intersected from the four stations: 

 16,344, 15,545, 16,168, and 16,664 feet elevation, the intersections giving 

 a very small triangular error. The elevation of Mount Coropuna 's high 

 peak as computed from these 4 stations is : 



21,696 feet 

 21,746 " 

 21,714 " 

 21,657 " 



Mean elevation 21,703 feet above sea level. 



The elevation of Coropuna as derived from these four stations has thus 

 a mean error of 18 feet (method of least squares) while the elevation of 

 each of the four stations as carried up from mean sea level through 25 

 stations — vertical angles being observed in both directions — has an esti- 



