VELAZQUEZ CARDENAS DE LEON, Joaquin (vay-lath'-keth), Mexican astronomer, born in Santiago Aubedocla, near Tizicapan, 21 July, 1732; died in Mexico, 6 March, 1786. He lost his father in childhood and was taken charge of by his uncle, the parish priest of Jaltocan, who educated him, and caused him to be instructed in Mexican history and mythology. He thus became familiar with several Indian languages, and with the hieroglyphic writing of the Aztecs. He was afterward placed in the Tridentine college of the city of Mexico ; but this institution was so poorly equipped with teachers, books, and instruments that he was almost self-educated in mathematics and the classics. Having met by chance with the works of Sir Isaac Newton and Francis Bacon, he became attracted by the discoveries of the one and the philosophic methods of the other. He had been graduated in law, and what he gained by his labors in this profession he spent in the purchase of instruments in England. After being appointed a professor in the university, he was sent on a mission to California, where he made a great number of astronomical observations. He was the first to notice that all the maps of that country had been for several centuries strangely in error with regard to its longitude, and made it extend several de-trees too far to the west. He built an observatory of mimosa logs at Santa Aria, with the assistance of the Abbe Chappe, a French astronomer, and predicted that the eclipse of the moon of 18 June, 1769, would be visible in California. Unaided, he made a very correct observation of the transit of Venus on 5 June, 1769. In 1774 he was charged with the execution of the topographical and geodetic survey of the valley of Mexico, and his labors, with this aim, have formed the basis of all those that have been undertaken since. After his return from California he placed before the government a project for the foundation of the School of mines. The greatest service that he rendered to his country was the establishment of this institution, of which he was director-general till his death. He wrote "Sobre el beneficio de las Minas del sur de California y demas de la N. Espana" and "Conocimientos interesantes sobre la Historia Natural de las cercanias de Mexico," manuscripts which were formerly in the library of the cathedral, and are now in the National library.