Alexis Bouvard’s career is an example of social promotion. Son of peasants, he came to fame through his gifts and his work. Arrived in Paris from Savoy at age 18, he attended the free courses at the Collège de France, and then managed to gain admission as a student-astronomer at the Paris Observatory in 1794. He made some of the long and difficult calculations of Pierre Simon Laplace, who had him admitted to the Board of Longitudes. He was elected in 1803 to the first class of the Institute of France (the provisional name of the Academy of Sciences). He was in charge of the Paris Observatory from 1809 to his death, but without the title of Director. A great observer, he discovered seven comets. But his main research was in celestial mechanics. He noticed an anomaly in the motion of Uranus that he attributed to the existence of a “disturbing planet.” This led Urbain Le Verrier to discover Neptune in 1846.