Overview of De Magnete
– De Magnete consists of six books.
– Book 1 provides a historical survey of magnetism and the theory of Earth’s magnetism.
– Book 2 distinguishes between electricity and magnetism, demonstrating the effects of cutting a spherical lodestone.
– Book 3 discusses the Earth’s normal magnetism and proposes magnetism as the cause of the angle of the ecliptic and precession of the equinoxes.
– Book 4 explores declination and the variations in the compass pointing to true north.
– Book 5 covers the angles of force on the terrella and magnetic dip.
– Book 6 focuses on terrestrial rotation and the diurnal revolution of the Earth.
– Gilbert argues in favor of the Copernican System and rejects the idea of a sphere of fixed stars.
– He explains how the inclination of the Earth’s pole to the ecliptic produces the seasons.
– The book discusses the cause of diurnal motion and its connection to magnetic energy.
– Gilbert infers the diurnal revolution of the Earth with certainty.
Gilbert’s Experiments and Theories
– Gilbert described experiments with his model Earth called the terrella.
– He claimed that gravity was due to the same force and believed it held the Moon in orbit.
– Gilbert explored static electricity produced by amber, referring to it as ‘electricus.’
– Amber is called ‘elektron’ in Greek and ‘electrum’ in Latin.
– The angle of inclination (dip) of a compass to the horizon differs according to latitude.
– Gilbert explains how to construct a dip instrument and shows that dip increases towards the poles.
– At the equator, the dip is level.
– The book also discusses the magnetic dip of the compass on the terrella.
Editions of De Magnete
– De Magnete was first published in 1600 by Peter Short in Latin.
– The second edition was published in 1628 by Wolfgang Lockmans in Latin.
– A facsimile of the first edition was published in 1892.
– An English translation by Paul Fleury Mottelay was published in 1893.
– Various other editions and translations have been published over the years.
Magnetism and Earth’s Magnetism
– Gilbert’s work in De Magnete focuses on magnetism and Earth’s magnetism.
– He provides a historical survey of magnetism and the theory of Earth’s magnetism.
– Gilbert distinguishes between electricity and magnetism.
– He demonstrates the effects of cutting a spherical lodestone.
– Gilbert proposes magnetism as the cause of the angle of the ecliptic and precession of the equinoxes.
– He explores declination and the variations in the compass pointing to true north.
Terrestrial Rotation and Diurnal Revolution
– Book 6 of De Magnete focuses on terrestrial rotation and the diurnal revolution of the Earth.
– Gilbert argues in favor of the Copernican System and rejects the idea of a sphere of fixed stars.
– He explains how the inclination of the Earth’s pole to the ecliptic produces the seasons.
– The book discusses the cause of diurnal motion and its connection to magnetic energy.
– Gilbert infers the diurnal revolution of the Earth with certainty. Source: https://en.wikipedia.org/wiki/De_Magnete
