Third and definitive edition. The importance of magnetism raised during the era of explorations by sea as the magnetic declination could be used to determine geographical longitudes. While the first Western written document about terrestrial magnetism is dated about 1190 magnetic declination (the angle between the direction of the compass and the geographic north) and its variation from place to place was observed by Spanish and Portuguese navigators from the fifteen and sixteen centuries (see Martín Cortés: Breve compendio de la sphera y de la arte de navegar, 1551; Robert Norman, 1581). While fellow Jesuits professors wrote on the subject (Garzoni, Cabeo) Kircher devoted years of observation and several works to magnetism, becoming one of his favorite subjects.
The first Kircher’s publication on magnetism is Ars Magnesia, short work published in 1631 during his early teaching Heiligenstadt. In 1641 Magnes sive de arte magnetica (The magnet or the magnetic art) is issued, re-published two years later and enlarged in 1654. Magnes is a large book in folio size with numerous detailed engravings divided into three books: 1. De natura et facultatibus magnetis (Nature and capacities of magnets), 2. Magnes applicatus (Applications of magnets), 3. Mundus sive catena magnetica (World or magnetic chain). Magnetism reappears in 1664 in parts of Mundus subterraneus (Subterranean world) and in 1667 in Magneticum naturae regnum (The magnetic kingdom of nature).
Provenance: Bibliotheca Pertinet (ownership entry at title-page dated 1660) – Kurt Herberts (modern ex-libris on final endpaper and on back cover) Provenance: Bibliotheca Pertinet (ownership inscription on title dated 1660) – Kurt Herberts (modern stamp on final endpaper and on back cover).
Bibliography: Caillet 5780; DSB VII, pp. 374-378; De Backer & Sommervogel IV, cols. 1048-1049; Poggendorff I, pp. 1258-1259; Fletcher, Athanasius Kircher (2011), p. 565 (no. 5b) & passim.
