GAMA, Antonio Leon de, Mexican astronomer, born in the City of Mexico in 1735; died there, 12 September, 1802. He studied in the College of San Ildefonso, early showing a taste for astronomy. As the means for a course in that science were wanting at that time in Mexico, he instructed himself by reading the works of Newton. Woebler, Gravesand, Muschembrock, Bernaulis, La Caille, and other eminent writers. He was for many years a clerk in the office of the secretary of the Supreme Court, and nothing would have been known of his scientific work if the astronomer La Lande had not published in his "Connaissement des temps" Gama's name as that of the author of the first exact observation of the longitude of Mexico, and eulogized his calculation of the eclipse of the sun of 6 November, 1771, which he promised to publish in the memoirs of the Academy of Paris. At the same time he commissioned Gama to take observations of the satellites of Jupiter, and of the tides on the Pacific coast from Acapulco to Valparaiso. This called the public attention to the merits of Gama, and the scientist Joaquin Velasquez de Leon, at the foundation of the Mining school, appointed him professor of mechanics, pyrotechnics, and aerometry, and commissioned him to make observations upon the impending eclipse of the sun and other celestial phenomena. The viceroy, Manuel Flores, who was himself a distinguished mariner and geographer, commissioned him to calculate the probable date of appearance of a comet, which had been predicted by the London astronomers for 1788. The necessity of providing for his family forced Gama to give time to mechanical pursuits, which would have been better employed in the service of science. But he still found leisure to write on experimental physics, medicine, mathematics, and Mexican antiquities, of which he exhibited profound knowledge. When in 1790 the Aztec calendar-stone was discovered, he published an essay about it, "Historical and Chronological Description of Two Stones that were found in the Plaza of Mexico upon the Occasion of laying the New Pavement," explaining for the first time its use among the Indians. Also, a treatise on their arithmetic, gnomonics, and hieroglyphics. Prescott praises Gama as treating his subject, not with the accustomed credulity of the antiquarian, but with the caution of a mathematician, who demonstrates whatever he asserts. Gama's only work preserved in book-form is "Descripcion Orografica del Eclipse del Sol, el 24 de Junio de 1778" (Mexico, 1778).