Niccolò Cabeo

Niccolò Cabeo (Ferrara, 1586 – Genoa, 1650) was an Italian Jesuit philosopher, best known for his work on magnetism and electricity, though he also worked as a theologian, engineer and mathematician. He trained in philosophy and theology at Jesuit colleges in Parma, Padua, Piacenza and Mantua, and later taught theology and mathematics in Parma. In 1622 he became a preacher. For a time he enjoyed the patronage of the Dukes of Mantua and the Este family in Ferrara, and during those years he took part in hydraulic projects. He finished his career teaching mathematics in Genoa, where he died.

His contributions to physics grew out of careful observation and experiment. He examined the falling-body experiments of Giovanni Battista Baliani and held that different objects fall in the same time whatever the medium. He also worked with pendulums, and he described how an electrified body attracts unelectrified objects and how two charged bodies repel each other. These observations appeared in the Philosophia magnetica (1629), which studies the cause of terrestrial magnetism and engages closely with William Gilbert. Believing the Earth to be motionless, Cabeo rejected its motion as the source of the magnetic field. To explain electrical attraction he proposed effluvia that pushed aside the surrounding air; as the air returned, it carried light bodies towards the attracting material.

His second major work, a commentary on Aristotle's Meteorology (1646), takes up Galileo's ideas, including the Earth's motion and the law of falling bodies, and opposes them. He also clashed with Benedetto Castelli over the rerouting of the Reno River. The Accademia del Cimento and Robert Boyle tested his ideas through experiments with vacuums. His lasting influence lies chiefly in those experiments and the debate they sparked about electricity and magnetism, and the lunar crater Cabeus bears his name.