The theory of electricity and its inseparable effect, magnetism , is probably the most accurate and complete of all scientific theories. The understanding of electricity has led to the invention of motors, generators, telephones, radio and television, X-ray devices, computers, and nuclear energy systems. Electricity is a necessity to modern civilization. Electric Charge Amber is a yellowish, translucent mineral. For centuries this strange, inexplicable property was thought to be unique to amber.
Electricity repels the same kind and attracts the opposite kind of electricity.
They did not realize that an equal amount of opposite electricity remained on the fur or silk. The action of rubbing merely transfers the fluid from one body to another, electrifying both. Franklin defined the fluid, which corresponded to vitreous electricity, as positive and the lack of fluid as negative. A subsequent two-fluid theory was developed, according to which samples of the same type attract, whereas those of opposite types repel. Lightning Franklin was acquainted with the Leyden jar, a glass jar coated inside and outside with tinfoil.