[The Jesuit Athanasius Kircher and his organum mathematicum].

P. Athanasius Kircher SJ (1602-1680) was a man of great erudition who carried out research in both the natural sciences and the humanities. He drew one of the first maps of the moon, performed microscopic studies of blood, worked on hieroglyphics and described China. He also invented the so-called Organum mathematicum. The device (located in Florence) has nine compartments containing wooden slats devoted to various mathematical subjects: arthmetic, geometry, fortifications, chronology, horography, astronomy, steganography (encryption) and music.