1700 - 1749

Aided by tools such as static electricity machines and leyden jars, scientists continue their experiments into the fundamentals of magnetism and electricity.

1706

Newton's Opticks

English physicist Sir Isaac Newton publishes Opticks, his collection of papers relating to light, color and optics. In it he outlines his corpuscular theory of light that holds that light is made up of particles, not waves, as other scientists had suggested.
1706

Friction = electricity

electrostatic generatorFrancis Hauksbee of London invents an electrostatic generator composed of a glass sphere turned by a crank that produces an electric charge through friction. This is a significant improvement over the more primitive version produced by Otto von Guericke several decades earlier.
1708

Insights into lightning

English scientist William Wall notes a similarity between thunder and lightning and the cracking sounds and sparks produced by electrified objects. His observations are published in Philosophical Transactions.
1709

Studies in electroluminescence

Physico-Mechanical Experiments on Various Subjects. Containing an Account of Several Surprizing Phenomena Touching Light and Electricity is published by Francis Hauksbee and becomes an important early work in the areas of electricity and electroluminescence.
1716

The Northern lights

English mathematician and astronomer Edmond Halley correctly speculates that the atmospheric phenomenon of aurorae is related to the effects of the magnetic field of the Earth.
1722

True and magnetic north

Through close observation of the needle of a compass, London instrument maker George Graham discovers the diurnal variation of magnetic declination.
1729

Surface charge

Chemist Stephen Gray of London demonstrates the conductivity of electricity and determines that it is the surface of an object that holds its charge.
1733

Two types of electricity

French chemist Charles-François de Cisternay du Fay speculates that there are two different types of electricity, which he refers to as resinous (-) and vitreous (+), notes the repulsion of like charges and the attraction of unlike charges, and determines that string is more conductive when wet.
1742

Principia edition

Thomas Le Sueur and Francis Jacquier publish an edition of Isaac Newton’s Principia and include a note to the text that demonstrates an inverse-cube law of the force between two magnets.
1745

Leyden jar

Leyden JarThe Leyden jar, the first practical device for storing electric charge, is invented independently by German cleric E. Georg von Kleist and Dutch physicist Pieter van Musschenbroek.
1745

Continuous electricity

Jean-Antoine Nollet, a French clergyman and physicist, theorizes that electrical matter continuously flows between two charged objects.
1745

Longer life for magnets

English physicist Gowin Knight develops a method of producing artificial magnets that retain their magnetization for extended periods of time. The new magnets are used in the Knight compass, which becomes very popular among mariners and scientists.
1746

Human conductors

In a demonstration of electricity for King Louis XV, Jean-Antoine Nollet discharges a Leyden jar so that the current passes through a line of 180 Royal Guards. He would later carry out a similar feat involving a chain of Carthusian monks that extended more than a kilometer.
1746

Theory of conservation

British scientist William Watson develops the concept of the conservation of electrical charge, in which there exists a single electrical fluid that is not created or destroyed, but only transferred from one object to another. Soon after, Benjamin Franklin more fully develops the theory of conservation.
1746

Trying to telegraph

Johann Heinrich Winckler, a professor at the University of Leipzig, tries to use electricity to communicate telegraphically across long distances.
1747

Measuring conductivity

English physicist and chemist Henry Cavendish begins measuring the conductivity of various substances by comparing the shocks he receives when he discharges Leyden jars through them.
1748

Electric velocity

William Watson, Henry Cavendish and other colleagues attempt to measure the velocity of electricity as it traveled through a circuit more than 12,000 feet long and mistakenly conclude that it is instantaneous.
1748

Early electroscope

Jean-Antoine Nollet builds an early electroscope, an electrometer comprised of a suspended pith ball that moves in response to the electrostatic attraction and repulsion of a charged body.
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