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ELECTRICITY

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Originally appearing in Volume V09, Page 180 of the 1911 Encyclopedia Britannica.
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ELECTRICITY . This See also:

article is devoted to a See also:general See also:sketch of the See also:history of the development of See also:electrical knowledge on both the theoretical and the See also:practical sides. The two See also:great branches of electrical theory which concern the phenomena of electricity at See also:rest, or " frictional " or " static " electricity, and of electricity in See also:motion, or electric currents, are treated in two See also:separate articles, See also:ELECTROSTATICS and See also:ELECTROKINETICS. The phenomena attendant on the passage of electricity through solids, through liquids and through gases, are described in the article See also:CONDUCTION, ELECTRIC, and also See also:ELECTROLYSIS, and the propa, gation of electrical vibrations in ELECTRIC WAVES. The inter-connexion of See also:magnetism (which has an article to itself) and electricity is discussed in See also:ELECTROMAGNETISM, and these manifestations in nature in ATMOSPHERIC ELECTRICITY; See also:AURORA POLARIS and MAGNETISM, TERRESTRIAL. The general principles of electrical See also:engineering will be found in ELECTRICITY See also:SUPPLY, and further details respecting the See also:generation and use of electrical See also:power are given in such articles as See also:DYNAMO; See also:MOTORS, ELECTRIC; See also:TRANSFORMERS; See also:ACCUMULATOR; POWER TRANSMISSION: Electric; See also:TRACTION; See also:LIGHTING: Electric; See also:ELECTROCHEMISTRY and See also:ELECTROMETALLURGY. The principles of telegraphy (See also:land, submarine and wireless) and of telephony are discussed in the articles See also:TELEGRAPH and See also:TELEPHONE, and various electrical See also:instruments are treated in separate articles such as See also:AMPERE-See also:METER; See also:ELECTROMETER; See also:GALVANOMETER; See also:VOLTMETER; See also:WHEATSTONE'S See also:BRIDGE; See also:POTENTIOMETER; METER, ELECTRIC; See also:ELECTROPHORUS; See also:LEYDEN See also:JAR; &C. The See also:term " electricity " is applied to denote the See also:physical agency which exhibits itself by effects of attraction and repulsion when particular substances are rubbed or heated, also in certain chemical and physiological actions and in connexion with moving magnets and metallic circuits. The name is derived from the word electrica, first used by See also:William See also:Gilbert (1544–1603) in his See also:epoch-making See also:treatise De magnete, magneticisque corporibus, et de magna magnete tellure, published in 1600,1 to denote substances which possess a similar See also:property to See also:amber (= See also:electrum, from i XeKrpov) of attracting See also:light See also:objects when rubbed. Hence the phenomena came to be collectively called electrical, a term first used by William Barlowe, See also:archdeacon of See also:Salisbury, in 1618, and the study of them, electrical See also:science. See also:Historical Sketch. Gilbert was the first to conduct systematic scientific experiments on electrical phenomena.

See also:

Prior to his date the scanty knowledge possessed by the ancients and enjoyed in the See also:middle ages began and ended with facts said to have been See also:familiar to Thales of See also:Miletus (600 B.C.) and mentioned by See also:Theophrastus (321 B.C.) and See also:Pliny (A.D. 70), namely, that amber, See also:jet and one or two other substances possessed the power, when rubbed, of attracting fragments of See also:straw, leaves or feathers. Starting with careful and accurate observations on facts concerning the mysterious properties of amber and the lodestone, Gilbert laid the See also:foundations of See also:modern electric and magnetic science on the true experimental and inductive basis. The subsequent history of electricity may be divided into four well-marked periods. The first extends from the date of publication of Gilbert's great treatise in 1600 to the invention by See also:Volta of the voltaic See also:pile and the first See also:production of the electric current in 1799. The second See also:dates from Volta's See also:discovery to the discovery by See also:Faraday in 1831 of the See also:induction of electric currents and the creation of currents by the motion of conductors in magnetic See also:fields, which initiated the era of modern electrotechnics. The third covers the See also:period between 1831 and Clerk See also:Maxwell's enunciation of the electromagnetic theory of light in 1865 and the invention of the self-exciting dynamo, which marks another great epoch in the development of the subject; and the See also:fourth comprises the modern development of electric theory and of See also:absolute quantitative measurements, and above all, of the applications of this knowledge in electrical engineering. We shall sketch briefly the historical progress during these various stages, and also the growth of electrical theories of electricity during that See also:time.

End of Article: ELECTRICITY

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