Although, at the beginning of the “gold rush” to California in 1849, the Salton Sink had been known to the Spaniards for more than three centuries, and to American explorers for at least twenty years, no scientific examination of it had ever been made. Four years later, however, in 1853, Jefferson Davis, who was then Secretary of War, prevailed upon Congress to authorize a series of explorations for the discovery of a practicable railroad route to the Pacific Coast. Lieutenant R. S. Williamson, of the United States Topographic Engineers, was selected as leader of the southern expedition, and with him, as geologist, went Professor William P. Blake of New York, a young graduate of the Yale Scientific School, who afterward attained great distinction as geologist, explorer and mining engineer, in fields as widely separated as Arizona, Alaska and Japan. Professor Blake was the first to explain the origin of the Salton Sink, to trace its ancient history, and to give a name to the great fresh-water lake that it had once held. He was also the first to suggest the possibility of irrigating it, and to predict that when it should be supplied with water it would “yield crops of almost any kind.” Reclamation of desert areas is now comparatively common; but sixty years ago, only a bold and original mind could have entertained the idea of getting crops out of such a “Death Valley” as the Salton Sink then was. Professor Blake, however, had the imagination of an investigator, tempered by the accurate knowledge of a scientist, and he could see that the sedimentary deposits in that ancient sea-basin needed only water to make them fertile.