N September, 1908, I left New York as a delegate of the United States Government and of Yale University to the First pan-american Scientific Congress, held at Santiago, Chile, in December and January, 1908 — 09. Before attending the Congress I touched at Rio de Janeiro and the principal coast cities of Brazil, crossed the Argentine Republic from Buenos Aires to the Bolivian frontier, rode on mule back through southern Bolivia, visiting both Potosi and Sucre, went by rail from Oruro to Antofagasta, and thence by steamer to Valparaiso. After the Congress I retraced my steps into Bolivia by way of the west coast, Arequipa, and Lake Titicaca. Picking up the overland trail again at Oruro, I con tinued my journey across Bolivia and Peru, via La Paz, Tiahuanaco, and Cuzco, thence by mules over the old Inca road as far as Huancayo, the present terminus of the oroya-lima Railroad. At Abancay I turned aside to explore Choqquequirau, the ruins of an Inca fortress in the valley of the Apurimac; an excursion that could not have been undertaken at all had it not been for the very generous assistance of Hon. J. J. Nunez, the Prefect of Apurimac, and his zealous aide, Lieutenant Caceres of the Peruvian army. I reached Lima in March, 1909.