ELE 



ELE 



is known in America by the name of fire- 

 fly. 



ELATE'RIUM {k\ar}']ptoi, driving 

 away). A terra applied by Richard to 

 the tricoccous capsule of Euphorbia, in 

 which the cells burst from the axis with 

 elasticity into two valves. See Regma. 



ELEA'TIC PHILOSOPHY. A sys- 

 tem of philosophy introduced by Xeno- 

 phanes of Elea, or Velia of the Romans. 

 Its object was to deny the validity of the 

 testimony of sense and experience, and 

 to ascribe to reason exclusively the merit 

 of arriving at the truth, independently of 

 any attempt to reconcile appearance and 

 reality. 



ELECTRICITY (fjXeKrpov, amber). 

 The science which investigates the attrac- 

 tions and repulsions, the emission of 

 light and explosions, which are produced, 

 not only by the friction of vitreous, resin- 

 ous, and metallic surfaces, but by the 

 heating, cooling, evaporation, and mu- 

 tual contact of a vast number of bodies. 



1. Electricity, vitreous and resinous. 

 1. Vitreous electricity comprises the 

 phenomena exhibited on rubbing surfaces 

 of glass. This is also called plus or posi- 

 tive electricity, and it denotes that the 

 substance is overcharged. 2. Resinous 

 electricity relates to the phenomena dis- 

 played on rubbing amber or resinous sub- 

 stances. This is also called minus or 

 negative electricity, and it denotes that 

 the substance is undercharged. 



2. Electrics and non-electrics. The 

 former are bodies capable of electric ex- 

 citement ; the latter are bodies totally 

 incapable of it. These terms were for- 

 merly supposed to be respectively syno- 

 nymous with non-conductors and con- 

 ductors ; but the distinction is quite inac- 

 curate, since a conductor may be also an 

 electric, if excited in an insulated state. 



3. Electric circuit. The communica- 

 tion of electricity from one body to an- 

 other is effected by means of metallic 

 wires. It is said to move in a current, 

 from an overcharged to an undercharged 

 body ; this current is termed the electric 

 circuit. If the communication be ar- 

 rested by bad conductors, the circuit is 

 said to be broken ; it is at this point of 

 the circuit that bodies are placed, through 

 which tl;ie electrical current is to be 



4. Electrical machine. An apparatus 

 for developing a large quantity of elec- 

 tricity of high tension. It consists of 

 1, a non-conductor, usually of glass, which 

 is positively excited by friction; 2, a 

 117 



rubber, or soft, elastic substance, of low 

 conducting power, which is negatively 

 excited; and 3, two conductors, which 

 are hollow, insulated, metallic cylinders, 

 the one for receiving the positive elec- 

 tricity of the glass, the other, the nega- 

 tive electricity of the rubber ; the former 

 is called the positive, the latter the nega- 

 tive conductor. 



5. Electric current. The discharge of 

 electricity by convection, or the transfer 

 of the two electrical forces in opposite 

 directions, defined by Faraday as " an axis 

 of power having contrary forces, exactly 

 equal in amount, in contrary directions." 



6. Electrical column. A species of 

 electrical pile, invented by De Luc, com- 

 posed of thin plates of diflTerent metals in 

 the usual order, with discs of writing 

 paper interposed between them. 



ELECTRICITY, ANIMAL. Galvan- 

 ism. A power possessed by, and evolved 

 from, certain living animals, by means of 

 which several of the phenomena, exhi- 

 bited by common and by voltaic elec- 

 tricity, are produced. Volta proved, that 

 the phenomena proceeded from the con- 

 tact of two dissimilar metals, copper and 

 iron, producing such a disturbance of the 

 electric equilibrium, as was sufficient to 

 affect the most delicate of all electro- 

 scopes, the irritability of a newly-killed 

 frog, though it was insensible to every 

 electroscope of human construction. 



ELECTRO-CHEMISTRY. A system 

 of chemistry based on the assumption that 

 the attractive force of opposite electricities 

 is the fundamental cause of all chemical 

 combination; every compound substance, 

 therefore, consists of one positively and 

 one negatively electrified element. 



ELE'CTRODE. A term in Electricity, 

 synonymous with pole, denoting the way 

 {666^) by which the electric current 

 enters or departs. It is, therefore, the 

 boundary of the decomposing matter in 

 the direction of the electric current, the 

 anode being the point at which the elec- 

 tricity enters, or the point immediately 

 touching the positive pole ; the kathode, 

 the point at which the electricity departs, 

 or the point next to the negative pole. 



ELECTRO-DYNAMICS. The science 

 which investigates the phenomena of 

 electricity in motion ; and this comprises 

 the phenomena of electro-magnetism 

 and magneto-electricity. 



ELECTRO'LYSIS (Xwco, to decom- 

 pose). The process of resolving a com- 

 pound body into its elements, or proxi- 

 mate principles, by the voltaic current. 



