1873
Maxwell's treatise
Scottish physicist James Clerk Maxwell provides a detailed discussion of his theory of electromagnetism in his Treatise on Electricity and Magnetism.
1873
Photoconductivity
English electrical engineer Willoughby Smith discovers photoconductivity when he observes that selenium conducts electricity better when exposed to light.
1874
Charge of an electron
Irish physicist George Stoney estimates the charge on the particle of electricity which he would later call the electron.
1875
Kerr electro-optic effect
Physicist John Kerr of Scotland discovers that birefringence can be induced in a transparent material by applying a strong electric field so that it is transverse to the light beam, a phenomenon now referred to as the Kerr electro-optic effect.
1876
Charge and current
American physicist Henry Rowland experimentally proves that a moving electric charge is magnetically equivalent to an electric current.
1876
Patent for telephone

1876
A better arc lamp
Russian electrical engineer and inventor Paul Jablochkov develops an improved arc lamp with a simple design known as the Jablochkov candle, which becomes the preferred form of electric street lighting for several years.
1879
Incandescent bulb
English physicist Joseph Swan, who had invented a primitive electric light in 1860, demonstrates a practical incandescent light bulb in his country; inventor Thomas Edison makes a similar demonstration of the electric light he independently invented in America.
1879
Hall effect
At the suggestion of Henry Rowland, American physicist Edwin Hall carries out an experiment while working on his doctoral thesis that results in his discovery of the Hall effect, which refers to the voltage difference produced by a magnetic field applied perpendicularly to a solid carrying an electric current.