William Gilbert, the London physician and philosopher was appointed chief doctor to the strong-willed and aged Virgin Queen Elizabeth I. Gilbert was the publisher of a book called "On the Magnet, Magnetick Bodies Also, and on the Great Magnet the Earth; a New Philosophy Demonstrated by Many Arguments and Experiments." He came up the the theory that the earth's interior was "a pure, continuous magnetic core, which orients our globe in the heavens just as it swings a compass needle to the north." Gilbert did not stop at amber. He started testing materials such as glass, rock crystal, sulfur, sealing wax, and some minerals, he found that when rubbed together they also became "electric." Gilbert's great electrical discovery was that: numerous hard materials could be electrified when rubbed. Gilbert used a nonmagnetic pivoted light gilt needle to study which materials had electrostatic attraction. The way this worked was that the needle would either swing towards or away from the material depending of whether it had a positive or negative charge. The term "electrical effluvia" was an invisible watery substance that Gilbert believed activated the numerous motions of attracting and repulsing. In 1603 Queen Elizabeth died followed by Gilbert, who was the first philosopher to use the term electric.
References:Jill Jonnes- Empires of Light:Edison, Tesla, Westinghouse, and the Race to Electrify the World (pages 18-20)

Luigi Galvani, a forty-four year old, man was dissecting a pair of frog legs on January 26, 1781 with the help of his assistants. With an electrostatic machine close by producing electricity his assistant touched a frog leg with a scalpel and at that moment the leg, unattached to any frog, jerked as if alive. At the sight of this Galvani repeated the experiment excepted touching the other end of the crural nerve with his scalpel while his assistant drew sparks from the machine. As instantly as the sparks occurred the frog leg was seizing with convulsions. Philosophers from all around the world started repeating Galvani's "animal electricity" experiments. This would ultimately start the feud of animal versus metallic electricity between Galvani and Alessandro Volta. Volta believed the electricity came from the metal and in 1794 formally challenged Galvani to refute his, Volta's, findings. While Galvani's supporters came back with an experiment including no metal and the frog still convulsed, Galvani was still morning the death in 1790 of his wife. After refusing the take an oath of allegiance to Napoleon Bonaparte's new government he was removed from the University of Bologna and in early December of 1798 Luigi Galvani died at the age of sixty one. Later, Galvani would have a term named after him, Galvanic, which meant, steady direct current.
References:Jill Jonnes- Empires of Light:Edison, Tesla, Westinghouse, and the Race to Electrify the World (pages 29-31)

Alessandro Volta had already accomplished so much that he was inducted into London's prestigious Royal Society, but when Galvani made his discovery of "animal electricity" he challenged Galvani because he thought the electricity was "metallic." Volta's biggest invention was the first primitive battery which worked using pairs of copper and zinc disks stacked on top of each other with a cloth disk or pasteboard soaked with water separating them. As the zinc dissolved, hydrogen gas was produced at the surface of the copper. A steady direct current was then produced and flowed along the wires. Volta had produced the first steady generation of man-made current. On March 20, 1800 Volta sent a letter to the president of the London's Royal Society, Sir Joseph Banks, that letter was not read until June 26, 1800 due to the war between France and England. Due to his new invention Volta was made a count in the Napoleonic government and had the term volt, which measures the electrical force of a current. Being a newly wed, famous, and very wealthy Volta decided not to take a large role in the further advancement of his battery or electrical philosophy.

References:Jill Jonnes- Empires of Light:Edison, Tesla, Westinghouse, and the Race to Electrify the World (pages 30-33)

Humphry Davy was a young chemist arranged to build larger batteries in the basement laboratory of the newly opened Royal Institution. American born, Count Rumsford, hired Davy to give public lectures at the Royal Institution. Hundreds of people came to watch Davy and his brainy pyrotechnics and brilliant showmanship. Davy believe the electricity produced by Volta's battery was from electrochemical interactions and eventually in October 1807 demonstrated using a battery he constructed that it was true. Davy decomposed alkalies into potash and soda ash with electricity. From that he would extract new elements such as potassium and sodium. With this new invention and knowledge of the workings of electricity Davy married a wealthy heiress and was granted a knighthood to become Sir Humphry Davy. Now director of the Royal Institution had built a battery of two thousand pairs of plates in the basement laboratory in 1808. Using the immense battery Davy was able to pull more elements such as magnesium, calcium, barium, and strontium. He was also the inventor of the arc lights, in 1809 he showed off his new invention in front of his audience at the Royal Institution. They worked with two charcoal sticks acting as conductors. With one stick connected to a Voltaic pile the electricity would run up the stick, then Davy touched the second stick with the first one and sparks would burst where they met. They got their name because when the two sticks were pulled apart the light would travel in an arc between the sticks.

References:Jill Jonnes- Empires of Light:Edison, Tesla, Westinghouse, and the Race to Electrify the World (pages 34-35)

Joseph Henry, the leading American scientist after Ben Franklin, until Willard Gibbs, was a professor at Princeton University (Bailey). His important and chief scientific contribution was in the field of electromagnetism, where he discovered the phenomenon of self-inductance (unit of inductance was known at "the Henry") (Bailey). In one of his many experiments, Henry was able to be the first "to wind insulated wires around an iron core to obtain powerful electro magnet" (Bailey). From this, he was able to lift 2,300 pounds. In 1831, Henry conducted an experiment with a magnetic circuit. When it was broken, he observed large sparks that were generated from the magnets. From that he was able to deduced the property known as "self-inductance", the inertial characteristic of an electric circuit. The self-inductance of a circuit tends to keep the current flowing and prevent it from changing. It also determines the magnitude of the electromagnetic force (emf) induced in it (The Columbia Encyclopedia). Henry found that "the self-inductance is greatly affected by the configuration of the circuit, especially the coiling of the wire. He also discovered how to make non-inductive windings by folding the wire back on itself" (Bailey).

References:Jill Jonnes- Empires of Light:Edison, Tesla, Westinghouse, and the Race to Electrify the World; Princeton.edu


Michael Faraday was a British physicist and chemist who discovered the electromagnetic induction, hydroelectricity, atmospheric magnetism, laws of electrolysis, and the relationship between electricity and magnet (IEEE Virtual Museum). Out of all of his discoveries, the electromagnetic induction was the most important. In the autumn of 1831, Faraday conducted an experiment where he wound up a coil of wire around a straight iron core. He then got two bar magnets and made a triangle using the wrapped iron bar as the third side (he made a V out of the two magnets). When the V of the magnets were separated, breaking the magnetic current, current was induced in the coil (Jonnes 40). To further test this, Faraday got a "pencil-shaped magnet and simply moved it in and out of coiled wire" (Jonnes 40). The moving magnetic field produced bursts of current in the wire. However, Faraday was not satisfied and wanted to produce a continuous current.

After many experiments and tests, Faraday was able to produce a permanent continuous current by creating a current generator, which became the first electric dynamo. The simple set up consisted of a "twelve-inch copper disk on an axle that revolved between the opposite poles of a permanent magnet. On one side of the copper disk, a wire ran from the axle to a galvanometer. Then another wire led from the galvanometer to a metallic conductor held against the rim of the copper disk. When the coper disk revolved,disturbing and thus changing the magnetic field of the magnet, the galvanometer registered a continuous electric current" ( Jonnes 40). Faraday's law of electromagnetic induction says that an "electric current is set up in a closed circuit by a changing magnetic field" (Jonnes 41).

References: Jill Jonnes- Empires of Light:Edison, Tesla, Westinghouse, and the Race to Electrify the World; IEEE Virtual Museum

Charles F. Brush
Charles Brush was one of the first to act to exploit the commercial potential of using large dynamos in central power stations to energize multiple arc lamps distributed along streets. In 1877, he decided to abandon other business interests and devote his time to developing an arc-lighting system. He first installed arc lights in a Philadelphia store and then in a public square in Ohio. He began to accumulate patents covering his improvements and organized the Brush Electric Company in Cleveland to manufacture the system. His company grew quickly; it reportedly installed about 80% of the arc lights in the United States during the early 1880s. His dynamos used stationary field magnets which were very substantially built. The iron cores were enclosed by a thin sheet of copper to reduce the eddy-current loss, and the field windings were insulated from the core by several layers of heavy paper saturated with shellac varnish. Brush made other inventions to improve the system; he invented an automatic regulator designed to maintain a constant output when one or more lamps were short-circuited. He also invented the double-arc lamp, which could insert a fresh lamp when the carbon electrodes in one lamp were consumed. He also devised an automatic cutout for lights so that the entire circuit would not go out if one light failed. In 1913, the American Institute of Electrical Engineers (AIEE) chose Brush, an inventor-entrepreneur, as the fifth recipient of the Edison Medal for his contribution to the invention and development of the series arc lighting systems.

References: IEEE Xplore