The Great Magnet, the Earthby David P. Stern
Commemorating the 400th anniversary of "De Magnete" by William Gilbert of Colchester
In 1600, four hundred years ago William Gilbert, later physician to Queen Elizabeth I of England, published his great study of magnetism, "De Magnete"--"On the Magnet". It gave the first rational explanation to the mysterious ability of the compass needle to point north-south: the Earth itself was magnetic. "De Magnete" opened the era of modern physics and astronomy and started a century marked by the great achievements of Galileo, Kepler, Newton and others.
If you lived in London in 1600, you could have purchased "De Magnete" for seven shillings and sixpence. To read it, of course, you would have to know Latin, the language of science in 1600. You might have had the rare privilege of attending first runs of Shakespeare's plays in the "Globe" theatre--sitting in the balcony if you could afford it, standing in front of the stage if not. However, you might have had to weigh this pleasure against the peril of bubonic plague, which usually spread in the city during summer months.
This web site tells the story of Gilbert and his book--with glimpses of London in 1600, and with studies of magnetism before Gilbert. It then recounts the later history of the Earth's magnetism, including...
One could hardly find a more striking story of grand adventure in science!
- The remarkable discoveries of Halley, Coulomb, Oersted, Ampere and Gauss.
- The unexpected connection between sunspot activity and the Earth's magnetism.
- The deep-seated "'dynamo" believed to be responsible for the field.
- The strange reversals of the Earth's magnetic polarity.
- The role of magnetism in discovering the "drift" of continents.
- The extension of magnetism to space around Earth, even to other planets.