Pedro de Valdivia in 1540 made an expedition into the country of the Araucanian Indians of Chile, and was the first to explore the eastern base of the Andes in what is now Argentine Patagonia.
Actual or projected routes for telegraph cables across the deep sea have also been sounded with extreme accuracy in many cases; but beyond these lines of sounding the vast spaces of the ocean remain unplumbed save for the rare researches of scientific expeditions, such as those of the " Challenger," the " Valdivia," the " Albatross " and the " Scotia."
Among good local annalists may be mentioned Juan Gilberto Valdivia, who has written a history of Arequipa, and Pio Benigno Mesa, the author of the Annals of Cuzco.
Brooke, a midshipman of the U.S.N., invented the principle on the " Valdivia " in 1898-1899, and to those of the " Belgica " already foreshadowed by Nicolaus Cusanus in the 15th century in 1897-1898, the " Gauss " in 1902-1903, and the " Scotia " and by Robert Hooke in the 17th, of using a heavy weight so in 1903-1904.
From Peru the Spaniards advanced southwards to Chile, which was first unsuccessfully invaded (1535-37) by Diego de Almagro, and afterwards occupied (1540-53) by Pedro de Valdivia.
