For the southern hemisphere our records are naturally much rarer and of less antiquity than for the northern hemisphere, and until the tree-rings are investigated we cannot carry our study back beyond the sixteenth century. From some researches into the municipal archives of Santiago de Chile, latitude 33½° S., published by B. V. Mackenna in 1877, we can infer, however, that the general course of variation since 1520 was similar to that of corresponding regions in North America. Santiago lies in a semi-arid region where a temporary shortage of water is severely felt, the average annual rainfall being only 364 mm. (14.3 inches). The early travellers, however, make no specific mention of drought, and in 1540 Pedro de Valdivia crossed the desert of Atacama with a column of troops and cattle without inconvenience—a feat which would be difficult nowadays. In 1544 there were heavy rains and great floods in June. The next record is for the year 1609, recording another heavy flood on the Mapocho, which was repeated nine years later in 1618. The first recorded drought occurred in the years 1637 to 1640; there was another flood in 1647, after which came a series of severe droughts interrupted by occasional floods, which lasted until the close of the eighteenth century. The first half of the nineteenth century was again comparatively rainy. The records thus indicate a wet period centred about 1600, followed by a dry period during the eighteenth century, exactly parallel to the records from the United States and Europe. BIBLIOGRAPHY Huntington, E. “The climatic factor as illustrated in arid America.” Washington, Carnegie Institution, 1914. ——. “The fluctuating climate of North America.” _Geogr. J._ 40, 1912, pp. 264, 392. ——. “The pulse of Asia.” Boston and New York, 1907. ——. “World power and evolution.” New Haven, 1919. Pettersson, O. “Climatic fluctuations in historic and prehistoric time.” _Svenska Hydrogr.-Biol. Komm. Skrifter_, H. 5. Rabot, Ch. “Essai de chronologie des variations glaciaires.” _Bull. géogr. historique et descriptive_, No. 2, 1902. Brückner, E. “Klimaschwankungen seit 1700” ... Vienna, 1890. Hildebrandsson, H. H. “Sur le prétendu changement du climat européen en temps historique.” Upsala, _Nova Actae Regiae Soc. Sci._ (4), Vol. 4, No. 5, 1915. Brooks, C. E. P. “An historical notice of the variations of climate in Chile.” Washington, _Dept. Agric., U.S. Weather Bureau, Monthly Weather Rev._ 47, 1919, p. 637. CHAPTER XVIII CLIMATIC FLUCTUATIONS AND THE EVOLUTION OF MAN