mistake in not confirming the discovery of vanadium, and strongly reproached him. He continued to teach at the College of Mines until his death, a course that "could well have been taught at the Polytechnic school in Paris", according to Michel Chevalier, who visited del Río shortly before the latter's death. Death and recognition Andrés Manuel del Río died at 84 in 1849, after a long and productive academic career. His work and his liberal politics were important to the building of an independent Mexican nation. He was the founding professor of mineralogy at the College of Mines, which laid the base for the current Institute of Geology of the National Autonomous University of Mexico (UNAM). He was a member of the Spanish Royal Academy of Sciences in Madrid, the Wernerian Natural History Society of Edinburgh, the Royal Academy of Sciences of France, the Economic Society of Leipzig, the Linnean Society of Leipzig, the Royal Academy of Saxony and the Philosophical Society of Philadelphia. He was also president of the Geological Society of Philadelphia and the Lyceum of Natural History of New York. His extensive scientific work, besides the first identification of vanadium, included the discovery and description of various minerals and the invention of methods of extraction of minerals for use in the mining industry. After his death, the important mining district that includes Batopilas in Chihuahua was named in his honor. The Chemical Society of Mexico instituted the prestigious National Chemistry Prize "Andrés Manuel Del Río" in 1964, with the object of giving public recognition to the work done by chemical professionals who have made extraordinary contributions to raise the level and prestige of the profession. It is awarded with a medal containing the likeness of del Río and a commemorative plaque. Andrés Manuel Del Río, Luis E. Miramontes, inventor of the first oral contraceptive, and Mario J. Molina, winner of the Nobel Prize in Chemistry in 1995, are the three Mexican chemists of outstanding world significance. Miramontes won the "Andrés Manuel Del Río" Prize in 1986. Selected scientific works Elementos de Orictognesia o del conocimiento de los fósiles, prepared for use in the Real Seminario de Mineria de México, 1795. Analyse des deux nouvelles espéces minérales composées de séléniure de zinc et de sulfure de mercure. Annales des Mines, Paris, 5, 1829. Découverte de l'iodure de mercure au Mexique. Annales des Mines, Paris, 5, 1829. Elementos de