Electricity
By Corral9631

1570
Electricity
William Gilbert (15401603) demonstrates attractive and repulsive force from rubbing many substances together (electrostatic charge); calls them "electrics," and suggests the earth itself is a magnet. 
Electricity
Otto von Guericke (160286) constructs first friction machine to generate static charge, using a revolving ball of sulphur. 
Electricity
Stephen Gray (16961736) conducts experiments that show electricity moves. 
Electricity
Benjamin Franklin (170690) proposes the notion of positive and negative charge, conserving a balance except when a deficit is brought about by some means. His famous kite experiments, identifying lightning as a form of electrical discharge, take place in 1752. 
Electricity
Georg von Kleist (c.170048) and Pieter van Musschenbroek (16921761) invent the Leyden jar, the first condenser (capacitor). 
Electricity
Franz Maria Aepinus (17241802) presents the first mathematical treatment of electrical forces and constructs first condenser with parallel plates. 
Electricity
Henry Cavendish (17311810) anticipates later work of Coulomb and Ohm, but shuns publication. The concepts of potential difference and a zero reference point, a ground, are his. 
Electricity
Charles Augustin de Coulomb (17361806) works out reciprocal law of electrical force (varying inversely as the square of distance between two charges). 
Electricity
Luigi Galvani (173798) demonstrates electrical activity in living tissue, as in muscle and nerve. 
Electricity
Alessandro Volta (17451827) invents an electric battery, the first source of DC current. 
Electricity
Hans Christian Oersted (17771851) finds that current in a wire can deflect a nearby magnetic needle. 
Electricity
Andre Ampere (17751836) discovers that two wires carrying currents act as magnets to attract or repel each other; he describes the relation between current direction and magnetic field orientation. 
Electricity
Georg Simon Ohm (17891854) mathematically unites current, voltage, and resistance in the famous "law" bearing his name: V=IR. 
Electricity
Joseph Henry (17971878) constructs an electromagnet that can lift in excess of a ton. Demonstrates a telegraph in 1831. Independently he works out principles of magnetic induction at about the same time as Faraday, but publishes slightly later. 
Electricity
Michael Faraday (17911867) experimentally characterizes magnetic induction. The most thorough of early electrical investigators, he formulates the quantitative laws of electolysis, the principles of electric motors and transformers, investigates diamagnetic materials, and posits a physical reality for the indirectly observed magnetic and electrical lines of force. 
Electricity
Wilhelm Weber (18041891) and Karl Friedrich Gauss (1771851) successfully operate a telegraph between two distant buildings. They devise the first system of consistent units for electrical measurement. Gauss organizes a European network of observers to record strength and direction of the geomagnetic field. 
Electricity
Heinrich Lenz (180465) discovers, at about the same time as Henry and Faraday, that an induced current flows in a direction to oppose the change that induced itLenz's law. 
Electricity
Gustav Robert Kirchhoff (182487) publishes "circuit rules" for calculating electrical quantities in loop and junction configurationsthe sum of all potential drops is always zero. 
Electricity
Heinrich Ruhmkorff (180377) invents doublywound induction coil; some models produce arcs a foot or more in length. This leads to development of AC transformers. 
Electricity
James Clerk Maxwell (183179) describes electromagnetic field in four classic equations, which allow also calculation of the speed of light. Their solution predicts waves within the field. 
Electricity
William Crookes (18321914) and Johann Wilhelm Hittorf (18241914) independently discover "cathode rays," working with currents in glass tubes of improved vacuum quality. 
Electricity
Heinrich Hertz (185794) discovers and measures the waves, radio waves, predicted by Faraday and Maxwell. 
Electricity
Nikola Tesla (18671943) invents the first practicable AC motor and polyphase power transmission system, which revolutionizes industry and commerce. 
Electricity
Charles Proteus Steinmetz (18651923) contributes mathematical analysis of more complex nature of AC circuits.