We owe the invention of electrical motors, generators and transformers to experiments carried out by Michael Faraday a century and a half ago. He revolutionised empirical electrical science and provided the theoretical knowledge that James Clerk Maxwell would meld into modern electromagnetism.
Faraday was born into poverty and trained as a bookbinder but Faraday miraculously ascended the ranks of the scientific elite in a sparkling career spanning four decades. In his spare time at the bookbinder, he toyed with simple apparatus: Voltaic piles, coils of wire and glass cylinders for storing electric charge. In 1810, a 1-page entry in the Encyclopaedia Britannica kindled his interest in the nature of electricity: was it a fluid, and if so, how did it behave? The dry theory in the article did not satisfy Faraday's curiosity. He wanted to supplement his reading with observed facts, and he started with an electrostatic generator. With this he zapped his fingers with sparks and tasted electricity's sting on his tongue. He decided to learn as much as possible about electrostatics.
Young Faraday's London lacked a university but nevertheless bubbled with scientific display in theatres, philosophical societies and even private houses. He attended weekly lectures and demonstrations on electricity given by one John Tatum, a self-appointed populariser who conducted experiments at his home near Salisbury Square. Here, Faraday took notes and sketched the equipment on display. One evening, he showed his notebook to a wealthy customer who was a member of the Royal Institution, where the chemist Humphry Davy was playing to packed audiences of up to 700 people. Impressed by Faraday's industry, the customer arranged free admission to lectures at the institution. Some months later, he recommended Faraday for a position as Davy's assistant.
Davy's lucrative programme of lectures had financed a major research programme in electrochemistry, powered by the world's largest battery. By the use of electrolysis, he had already isolated the several elements from their host compounds. But then disaster struck in the laboratory: a powerful explosion of unstable nitrogen trichloride left Davy temporarily blinded. Faraday was summoned to act as amanuensis and later offered a permanent position at the Royal Institution, where he spent his entire career.
Faraday's first task was accompanying Davy on an 18-month grand tour. On their travels, they conducted chemistry investigations. In Florence, they used the sun's rays to ignite diamonds, thus proving that they are pure carbon. Alessandro Volta welcomed them in Milan. On return to London in 1815, Faraday worked under Davy's direction as an analytic chemist as well as a dogsbody. As assistant, he helped Davy on a subject of immense importance: the invention of the miner's safety lamp.
When news reached London in 1820 of Hans Christian Oersted's discovery that an electrical current in a wire has a magnetic effect, Faraday launched investigations into the field of electromagnetism. Incapable of understanding mathematical theories of electricity, Faraday instead made meticulous use of experiments to check the truth of his ideas. His first mechanical device capable of making a current-carrying wire rotate about a magnet led to a sharp clash with Davy, who alleged plagiarism and subsequently blocked his election to the Royal Society.
Faraday's experimental papers on electricity amount to 1,114 pages, without a single equation. In this corpus, Faraday proposed a new vision of nature, now known as field theory. He envisaged electromagnetism as operating through real, not hypothetical, lines of force. With this concept, the whole emphasis of his investigations shifted from material entities such as magnets and wires to the regions surrounding objects, where the tugs of force were seen to act.
Alan Hirshfeld's short scientific biography is a masterpiece of concision and clarity that brims with life. Faraday's deep commitment to the use of the scientific method to make the invisible visible shines out.
Simon Mitton is a fellow of St Edmund's College, Cambridge.
The Electric Life of Michael Faraday
Author - Alan Hirshfeld
Publisher - Walker and Company
Pages - 258
Price - $24.00
ISBN - 0 80 1470 6