Since its founding in 1891, many people have passed through the doors of the Vatican Observatory. A quick perusal of our guestbook reveals several Names, including Popes, nobel laureates, astronauts, actors, and saints.
Today's guestbook entry is from April 6, 1912, when Stanislas Meunier made a visit.
Next to his name, Stanislas-Étienne Meunier (1843-1925) wrote, "Muséum Paris." He was the chair of Geology at the Muséum National d'Histoire Naturelle (MNHN) in Paris, France.
In my field of meteoritics, his contributions are not insignificant. He compared the chemical compositions of meteorites with those elements identified in solar spectra. He recognized that (except for the most volatile elements) the elemental composition of meteorites closely matches that of the Sun. From this, he concluded that the overall composition of the solar system is effectively uniform.
He also introduced experimental geology as a distinct field of science. He contributed much to our understanding of the geology of the Paris Basin.