Electricity: Where Did It All Come From
Long before any knowledge of electricity existed people were
aware of shocks from electric eels. Ancient Egyptian texts dating from 2750 BC
referred to these fish as the "Thunder of the Nile", and described
them as the "protectors" of all other fish. Electric eels were again
reported millennia later by ancient Greek, Roman and Arabic naturalists.
Several ancient writers, such as Pliny the Elder and Scribonius Largus,
attested to the numbing effect of electric shocks delivered by catfish and
torpedo rays, and knew that such shocks could travel along conducting objects.
Patients suffering from ailments such as gout or headache were directed to
touch electric fish in the hope that the powerful jolt might cure them.
Possibly the earliest and nearest approach to the discovery of the identity of
lightning, and electricity from any other source, is to be attributed to Arabia
in the 15th century where the Arabic word for lightning (raad) was the same word
used for an electric eel.
Ancient cultures around the Mediterranean sea knew that
certain objects, such as rods of amber, could be rubbed with cat's fur to
attract light objects like feathers. Thales of Miletus made a series of
observations on static electricity around 600 BC, from which he believed that
friction rendered amber magnetic, in contrast to minerals such as magnetite,
which needed no rubbing. Thales was incorrect in believing the attraction was
due to a magnetic effect. The effect was due to static electricity, but later
science would prove a link between magnetism and electricity.
Electricity would remain little more than an intellectual
curiosity for millennia until 1600, when the English scientist William Gilbert
made a careful study of electricity and magnetism. He carefully examined the
fact that small objects are pulled towards amber after ir is rubbed. We know
this now as static electricity. He called
it electricus (from the Greek word elektron, for "amber"). Gilbert's
term led to the English words "electric" and "electricity",
which made their first appearance in print in 1646.
Further work was conducted by Otto von Guericke, Robert
Boyle, Stephen Gray and C. F. du Fay. In the 18th century, Benjamin Franklin
conducted extensive research in electricity, selling his possessions to pay for
his work. In June 1752 he is reputed to have attached a metal key to the bottom
of a dampened kite string and flown the kite in a storm-threatened sky. A
succession of sparks jumping from the key to the back of his hand showed that
lightning was indeed electrical in nature.
He also developed ideas, that proved
to be correct, about electricity consisting of both positive and negative
charges.
In 1791, Luigi Galvani published his discovery of
bioelectricity, demonstrating that electricity was the way that nerve cells passed
signals to the muscles in the human body. Soon after that, in 1800, Alessandro
Volta's invented the battery. It was made from thin layers of zinc and copper,
provided scientists with a more reliable source of electrical energy than any electrostatic
machines previously used. The recognition of electromagnetism, the unity of
electric and magnetic phenomena, is due to Hans Christian Ørsted and
André-Marie Ampère in 1820. Michael
Faraday invented the electric motor in 1821, figuring out how electricity can
be created from wires an magnets. In 1827 Georg Ohm developed the idea of an
electric circuit.
While the early 19th century had seen rapid progress in
electrical science, the late 19th century would see the greatest progress in
electrical engineering. Through such people as Alexander Graham Bell, Ottó
Bláthy, Thomas Edison, Galileo Ferraris, Oliver Heaviside, Ányos Jedlik, Lord
Kelvin, Sir Charles Parsons, Ernst Werner von Siemens, Joseph Swan, Nikola
Tesla and George Westinghouse, electricity turned from a scientific curiosity
into an essential tool for modern life, becoming a driving force of the modern
world.
