1850-1869

The Industrial Revolution is in full force, Gramme invents his dynamo and James Clerk Maxwell formulates his series of equations on electrodynamics.

1850

Magnetic susceptibility

William ThomsonIrish-Scottish scientist William Thomson (Lord Kelvin) introduces the concepts of magnetic susceptibility and permeability.
1850

Electricity & the body

French physician Guillaume Benjamin Armand Duchenne publishes information on his long-running study on facial muscles and their expression of emotion, discoveries made from applying electrical stimulus directly to or through the skin.
1851

Thermoelectricity

William Thomson (Lord Kelvin) publishes his general theory of thermoelectricity.
1852

Sunspots & magnetism

Edward Sabine, an English astronomer, discovers a correlation between the sunspot cycle and magnetic activity on Earth.
1853

RLC circuit theory

William Thomson (Lord Kelvin) derives the formula for magnetic energy and develops a theory of the RLC circuit.
1853

Animal electricity

German physicist Hermann von Helmholtz's work with electricity and muscle tissue leads him to publish "Some laws concerning the distribution of electric currents in conductors with applications to experiments on animal electricity." This work includes a mathematical demonstration of what is now known as Thévenin's theorem of electric circuits.
1853

Alliance Company

The Alliance Company is founded in Paris as a manufacturer of machines for generating electric current, which are originally intended for use by researchers carrying out work in electrochemistry.
1855

Maxwell's first essay

James Clerk MaxwellScottish physicist James Clerk Maxwell writes his first essay related to electricity, On Faraday's Lines of Force, in which he relates Faraday's conception of lines of force to the flow of a liquid and uses analytical mathematics to derive equations for electric and magnetic phenomena.
1856

Discoveries in Germany

German physicists Wilhelm Weber and Rudolf Kohlrausch measure the ratio of electrostatic to electromagnetic units and find that the quantity is analogous to the value of the speed of light accepted at that time.
1857

Signals through wire

Physicist Gustav Kirchhoff expands on the work of compatriots Weber and Kohlrausch, demonstrating that electromagnetic signals can be transmitted on a highly conductive wire at the speed of light.
1858

Bending cathode rays

Julius Plücker, a German physicist and mathematician, discovers that magnetic forces can cause the bending of cathode rays.
1858

Transatlantic cable

Transatlantic cableA transatlantic electric telegraph cable is successfully laid across the ocean floor, despite an earlier failed attempt. After just six weeks, the newly installed line stops working.
1858

Arc lighting

The first practical arc lighting system is installed in a lighthouse in England.
1859

Rechargeable battery

French physicist Gaston Planté builds the first rechargeable battery from two lead sheets rolled into a cylinder, submerged in a diluted sulfuric acid solution, and then charged.
1861

Lines of force

James Clerk Maxwell publishes his paper On Physical Lines of Force, in which he discusses the lines of force in mechanical terms.
1861

Transcontinental telegraph

The first transcontinental telegraph line is completed in America.
1861

First phone

German physics professor Johann Philipp Reis describes in a lecture an electric device he constructed that he dubbed the telephone. However, Reis's invention is unable to sufficiently reproduce most sounds, including human speech, and is never patented or further developed by him.
1864

Units of force

The Committee on Electrical Standards of the British Association for the Advancement of Science completes a report defining units of electromotive force and resistance based on millimeters, grams and seconds (mgs system). Less than 10 years later the group would recommend switching to a centimeter, gram and second (cgs) system.
1864

Maxwell's equations

The entire set of James Clerk Maxwell's electromagnetism equations appears in his paper On a Dynamical Theory of the Electromagnetic Field.
1866

Leclanché cell

Leclanché cellFrench engineer Georges Leclanché invents the dry cell battery that bears his name and continues to be widely used, albeit in a somewhat modified form, today.
1867

Lorenz's theory

Danish physicist Ludwig Lorenz independently develops an electromagnetic theory of light and shows that James Clerk Maxwell's equations can be derived from his scalar and vector potentials, though he disagrees with Maxwell's belief that ether was a necessary medium for the transmission of light.
1869

Gramme dynamo

Gramme dynamoZénobe-Théophile Gramme, an electrical engineer born in Belgium, invents a practical continuous-current electrical generator known as the Gramme dynamo, which a few years later is discovered by accident to be reversible so that it can also be utilized as an electric motor.
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