1825—Georg Simon Ohm discovered the relation between the voltage, ampereage and resistance in an electric circuit, which is called Ohm’s Law. The Ohm, the unit of electric resistance, is named in his honor for this discovery.
1831—Michael Faraday discovered that electricity can be generated by moving a wire in the neighborhood of a magnet, the principle of the dynamo.
1840—Sir William Robert Grove demonstrated his experimental incandescent lamp in which platinum is made incandescent by current flowing through it.
1841—Frederick De Moleyns obtained the first patent on an incandescent lamp. The burner was powdered charcoal operating in an exhausted glass globe.
1845—Thomas Wright obtained the first patent on an arc light.
1845—J. W. Starr invented an incandescent lamp consisting of a carbon pencil operating in the vacuum above a column of mercury.
1856—Joseph Lacassagne and Henry Thiers invented the “differential” method of control of the arc which was universally used twenty years later when the arc lamp was commercially established.
1862—The first commercial installation of an electric light. An arc light was put in a lighthouse in England.
1866—Sir Charles Wheatstone invented the “self-excited” dynamo, now universally used.
1872—Lodyguine invented an incandescent lamp having a graphite burner operating in nitrogen gas.