240 



ELECTRICITY. 



ELEMENTS. 



its conductive power fivefold. Another is the 

 Ian that light generates a current on striking 

 the platinum electrode of a voltameter. 



In further confirmation of Maxwell's electro- 

 magnetic theory of light, it has heen proved by 

 the experiments of Helmholtz, Fitzgerald, and 

 others, that Kre.-iiel'.- calculations of the in- 

 u-n-ity of light, reflected and refracted at the 

 surface of meeting of transparent media, agree 

 with this hypothesis in connection with the 

 one assumed as the explanation of the laws of 

 double refraction. 



Professor Sylvanus P. Thompson, Jamin, and 

 other eminent physicists, have formed a con- 

 ception of electricity which resembles the old 

 belief that it is a fluid substance. Experiments 

 appear to show that in its relations to energy 

 and matter it only acts as a transmitter of 

 energy, and is not convertible into it. The 

 quantity of electricity within a closed surface, 

 it has been demonstrated, can not be increased 

 or diminished without the entrance or outflow 

 of electricity. It is concluded, then, that elec- 

 tricity is a third entity, distinct from matter 

 and from energy, the total quantity of which 

 in the universe is conceived to be constant, as 

 is the total quantity of matter or of energy. 

 It resembles matter in that it requires the ex- 

 penditure of energy to set it in motion, and, 

 when its motion is arrested, its kinetic energy 

 reappears in the form of heat or an equivalent 

 form. The force with which a quantity of 

 electricity acts upon another varies inversely 

 as the square of the distance between them, 

 as does the mutual attraction of bodies, but 

 the effect is of the nature of repulsion instead 

 of attraction. Electricity may be imagined to 

 be a physical entity which does not possess 

 mass, but yet possesses a quality corresponding 

 to elasticity, and can be the recipient of energy 

 in both the kinetic and the potential forms, 

 and which tends to distribute itself equally 

 throughout space, and exercises a definite 

 pressure on those ultimate particles of matter 

 which it does not penetrate. Under this sup- 

 position electricity would fulfill all the functions 

 which are ascribed to the interstellar and in- 

 termolecular ether. The hypothesis of the im- 

 ponderable ether of space may be abandoned 

 in favor of the immaterial electricity which 

 may be assumed to fill all space. Light would 

 then be the vibrations of this elastic but im- 

 ponderable medium. Heat, or the equivalent 

 forms of energy, are the forms into which light 

 vibrations of electricity change when the vi- 

 brations are arrested or absorbed, just as the 

 vibration of matter, when arrested, changes 

 into heat or its equivalents. But it is only the 

 less refrangible rays that is, the vibrations of 

 greater wave-lengths which nearly agree in 

 period with the vibrations of molecules, and 

 are convertible into calorific energy. The 

 more rapid radiant vibrations, which produce 

 actinic effects, do not expend their energy in 

 thus intensifying molecular oscillations. Their 

 electro-chemical action is explained by their 



alternating displacements of the electricity of 

 space in the surface molecules of a chemical 

 compound which is decomposed by their ac- 

 tion, at certain stages of which rapidly re- 

 versed electromotive action electrolysis occurs. 



AVhile the phenomena of radiant energy and 

 the other problems which have led to the pos- 

 tulate of the hypothetical ether are satisfied la- 

 this theory of electricity, all electro-magnetic 

 phenomena can be explained by the supposition 

 of a constant tendency to the equalization of 

 inequalities in the distribution of electricity. 

 Electricity behaves like an incompressible thud 

 moving along stream-lines with the relative 

 pressures and tensions between the various 

 parts which would belong to such a fluid. A 

 body which contains an excess of electricity or 

 a deficiency as compared with neighboring 

 bodies tends to transfer to them, or they to it, 

 the quantity above or below the average 

 charge. The two conditions of electrification 

 known as positive or vitreous and negative or 

 resinous consist, according to this hypothesis, 

 of an excess or defect in the electricity con- 

 tained in a body compared with the ordinary 

 distribution. Which of these states is the sur- 

 charged condition has not been determined, 

 though the weight of evidence indicates that 

 it is that called negative and designated by the 

 minus sign, the state of electrification which 

 certainly tends more rapidly toward dissipation 

 or discharge than does positive or vitreous 

 electrification. The so-called minus, or, ac- 

 cording to these conclusions, excessive or true 

 plus electrification, is that possessed by the 

 earth relatively to the surrounding space. 



ELEMENTS, COMPOSITE NATUBE OF THE. 

 The spectroscopic studies of the materials of 

 the sun, of the hotter and the cooler stars, and 

 of the luminous nebula), have led to the belief 

 that most of the chemical elements, as they are 

 known to us, are compound bodies ; and that 

 they are all resolvable, though the means of dis- 

 sociating their components are beyond human 

 reach, into a very few simple gases, or perhaps 

 into one single ultimate form of matter. ]n 

 accordance with the nebular hypothesis, which 

 is strengthened by the probabilities of this 

 new theory, the many forms of matter are as- 

 sumed to have been progressively developed 

 from their ultimate constituents by the changes 

 in physical conditions through which the uni- 

 verse has passed, the condensation and refriger- 

 ation of the matter of which cooler heavenly 

 bodies, exemplified by our earth, are composed. 

 The reasons for assuming the elementary nature 

 of the so-called elements are, that they resist 

 all efforts to decompose them, and secondarily 

 that they enter in definite proportions into 

 chemical compounds. The property of chem- 

 ical stability is manifested in many degrees. 

 Many compound substances combine as radicles 

 and show a close resemblance to the elements 

 in their behavior in certain relations. The 

 building up of homogeneous substances from 

 materials which are themselves complex com- 



