GAY, Claude, French naturalist, born in Draguignan, 18 March, 1800 ; died in Paris, 6 April, 1863. In 1822 he went to Paris to assist at the course of lectures in the museum, in order to study zoology and prepare himself for voyages that he projected. After a preliminary excursion to Greece and Asia Minor, he went to Chili to study the flora of South America, arriving at Valparaiso in March, 1828. The results of this expedition were so important that the Chilian government commissioned him, in 1829, to take astronomical observations and prepare a scientific survey of the republic. But he was greatly hampered in his work by want of proper instruments, and in 1832 went to Paris, where, (luring a stay of six months, several instruments of his own invention were constructed for him. He returned to Chili in 1833, and began a ten-years' exploration of the republic, in which he visited every province and the islands of Juan Fernandez and the archipelago of Chiloe. He made also the most detailed bibliographic investigations, taking copies of every important document, and soon had gathered an enormous collection of historical facts and an herbarium of over 4,000 species. The government bestowed the highest honors upon him, and in 1841 congress appropriated the means to publish his work. He also explored Peru and the course of the Ucayali River, and visited Buenos Ayres and Rio Janeiro, and in 1843 returned to France, where he prepared for publication his great work "Historia Fisica y Politica de Chile" (Paris and Santiago, 1843-'51, 24 vols., with an atlas in 2 vols.). In May, 1856, Gay was elected a member of the Academy of sciences in the botanical section. He made a journey through Russia and Tartary in 1856-'8, and toward the end of the latter year was sent by the academy to study the mining system of the United States, returning in 1860. He published, besides his great work mentioned above, "Consideraciones sobre las Minas de Mercurio de Andacolla ,6 Illapel con su posicion Geoldgica" (Valparaiso, 1837 ; Paris, 1851) ; " Noticias sobre las islas de Juan Fernandez" (Valparaiso, 1840) ; "Origine de la Pomme de terre " (Paris, 1851; a translation of an article in "La Araucana" of Santiago in 1834) ; "Triple variation de l'aiguille aimantde dans les parties Ouest de l'Amdrique" (1854); "Carte generale du Chili" (1855) ; "Considerations sur les Mines du Perou, compardes aux mines du Chili" {1855); " Notes sur le Brdsil, Buenos Ayres, et Rio de Janeiro" (1856); and "Rapport a l'academie des sciences sur les mines des Etats-Unis " (1861).