Ars Magnesia

[4] The work is a 48-page pamphlet that appears to be a printed version of a lecture he had given some years previously while teaching at the Jesuit seminary in Heiligenstadt.

He cited the works of Pliny and Plutarch and suggested conserving a magnet’s strength by wrapping it in dried woad leaves.

He warned that leaving a magnet near a diamond or rubbing it with garlic would weaken it,[6] but its strength could be regained by pouring boar’s blood over it.

Years later in Rome, Kircher built machinery to demonstrate his propositions, allowing him to stage Jonah being swallowed by a whale by means of magnetism.

[9] Robert Boyle later wrote of magnetism that “the ingenious Kircher hath so largely prosecuted it in his voluminous Ars Magnetica (sic), yet he has not reaped his field so clean, but that a careful gleaner, may still find ears enough to make some sheaves.”[7] Kircher returned to the subject of magnetism several times in his later studies, publishing Magnes sive de Arte Magnetica (1641) and Magneticum Naturae regnum (1667).