Hidden Attraction

Book excerpt: Long one of nature's most fascinating phenomena, magnetism was once the subject of many superstitions. Magnets were thought useful to thieves, effective as a love potion or as a cure for gout or spasms. They could remove sorcery from women and put demons to flight and even reconcile married couples. It was said that a lodestone pickled in the salt of sucking fish had the power to attract gold. Today, these beliefs have been put aside, but magnetism is no less remarkable for our modern understanding of it. In Hidden Attraction, Gerrit L. Verschuur, a noted astronomer and National Book Award nominee for The Invisible Universe, traces the history of our fascination with magnetism, from the first discovery of magnets in Greece, to state-of-the-art theories that see magnetism as a basic force in the universe. The book begins with the early debunking of superstitions by Peter Peregrinus (Pierre de Maricourt), whom Roger Bacon hailed as one of the world's first experimental scientists (Perigrinus held that "experience rather than argument is the basis of certainty in science"). Verschuur discusses William Gilbert, who confronted the multitude of superstitions about lodestones in De Magnete, widely regarded as the first true work of modern science, in which Gilbert reported his greatest insight: that the earth itself was magnetic. We also meet Hans Christian Oersted, who demonstrated that an electric current could influence a magnet (Oersted did this for the first time during a public lecture) and Andre-Marie Ampere, who showed that a current actually produced magnetism. Verschuur also examines the pioneering experiments and theoretical breakthroughs of Faraday and Maxwell and Zeeman (who demonstrated the relationship between light and magnetism), and he includes many lively stories of discovery, such as the use of frogs by Galvani and Volta, and Hertz's accidental discovery of radio waves. Along the way, we learn many interesting scientific facts, perhaps the most remarkable of which is that lodestones are made by bacteria (a sediment organism known as GS-15 eats iron, converting ferric oxide to magnetite and, over billions of years, forming the magnetite layers in iron formations). Boasting many informative illustrations, this is an adventure of the mind, using the specific phenomenon of magnetism to show how we have moved from an era of superstitions to one in which the Theory of Everything looms on the horizon.