In 1820 he went to Germany to study the metallurgical district of Freiberg, and discovered a new substance, which he called Humboltina. He made known in Europe the sodium nitrate of Tarapaca, which soon became one of the principal exports of Peru. Afterward he made a scientific trip to Spain, visiting the mines, especially those of mercury at Almaden.

He returned to Paris in 1822, and there met Zea, the Colombian minister, by whom he was commissioned to go to Bogota to establish a mining-school. He selected some of his college companions to aid him; and on their arrival in Venezuela, where they were well received by General Bolivar, they began work, obtaining good results and making many discoveries.

After three years he was called by his family to Peru, and resigned the charge of director of the school, General Bolivar appointing him instead general director of mines and public instruction of Peru, which appointment was confirmed by General La Mar, president of that republic. After his arrival in 1825 he devoted his time to science, and, together with Nicolas de Pierola (q. v.), published, from 1826 till 1828, the "Memorial de Ciencias Naturales."

In 1829, during the civil war, he was deposed and obliged to retire to Chile, where he made extensive geological studies. On his return to Peru the government appointed him director of the Museum of Natural History and Antiquities of Lima. In 1832 he was a member of the national congress, as deputy for the province of Caylloma; but in 1834, on account of his health, he retired to Arequipa. In 1840 General Gamarra reinstated him in the direction of the museum and public works. In 1851 he accepted the charge of consul-general in Belgium, but he returned to Peru in 1852. In 1854 he again occupied his place in Belgium.

Rivero was a member of many foreign scientific societies. He wrote "Memoria sobre las aguas minerales de Yuro y otros puntos cercanos a Arequipa" (Lima, 1827) ; "Antiguedades Peruanas," with Dr. Johann Jakob von Tschudi (Vienna, 1851); "Apuntes estadisticos del Departamento de Junin" (Brussels, 1855); and "Colección de memorias cientificas, agricolas y industriales" (2 vols., 1856-'7).

RIVERO, Mariano Eduardo de (re-vay'-ro), Peruvian scientist, born in Arequipa in 1799; died in Paris, France, 6 November, 1857. At the age of" twelve he was sent to Europe and entered the college at Highgate, near London, studying chemistry under Sir Humphrey Davy. In 1816 he went to Paris, where, after many difficulties, he was admitted in 1818 to the Royal college of mines. In 1820 he went to Germany to study the metallurgical district of Freiberg, and discovered a new substance, which he called Humboltina. He made known in Europe the sodium nitrate of Tarapaca, which soon became one of the principal exports of Peru. Afterward he made a scientific trip to Spain, visiting the mines, especially those of mercury at Almaden. He returned to Paris in 1822, and there met Zea, the Colombian minister, by whom he was commissioned to go to Bogota to establish a mining-school. He selected some of his college companions to aid him ; and on their arrival in Venezuela, where they were well received by General Bolivar, they began work, obtaining good results and making many discoveries. After three years he was called by his family to Peru, and resigned the charge of director of the school, General Bolivar appointing him instead general director of mines and public instruction of Peru, which appointment was confirmed by General La Mar, president of that republic. After his arrival in 1825 he devoted his time to science, and, together with Nicolas de Pierola (q. v.), published, from 1826 till 1828, the "Memorial de Ciencias Naturales." In 1829, during the civil war, he was deposed and obliged to retire to Chili, where he made extensive geological studies. On his return to Peru the government appointed him director of the Museum of natural history and antiquities of Lima. In 1832 he was a member of the national congress, as deputy for the province of Caillolna; but in 1834, on account of his health, he retired to Arcquipa. In 1840 General Gamarra reinstated him in the direction of the museum and public works. In 1851 he accepted the charge of consul-general in Belgium, but he returned to Peru in 1852. In 1854 he again occupied his place in Belgium. Rivero was a member of many foreign scientific societies. He wrote " Memoria sobre las aguas minerales de Yuro y otros puntos cercanos a Arequipa" (Lima, 1827) ; " Antiguedades Peruanas," with Dr. yon Tschudi (Vienna, 1851); "Apuntes estadisticos del Departamento de Junin" (Brussels, 1855); and "Coleccion de memorias cientificas, agricolas d industriales" (2 vols., 1856-'7).