ELECTRONIC THEORY OF ELEC

TRIFICATION. Until late in the’19th cent. the phenomena of electrification were explained in accordance with the two-fluid theory of du Fay or the one fluid theory of Franklin. According to both these theories, electricity is @ weightle , indestructible fluid. But more modern research has finally exploded both these hypotheses, Recent investigation of the electric discharge through rarefied gases has proved that particles far smaller than the smallest atom exist, and always in a ociation with a certain definite charge of negative, electricity. These particles J. J. Thomson named corpuscles. But exactly the same charge is always a ociated with a single hydrogen atom in electrolytic proce (electrolysis); this charge has been regarded as the natural unit of electricity and called the electron. There is good ground for believing that the electron and the corpuscle are identical, and that the electron is in fact an ‘atom of negative electricity,’ and independent of gro matter. Under suitable cond i~ tions negative electrons may be freely expelled from matter by electrical forces, and they are found to travel through, vacua with a speed comparable to that of light. It has been calculated that the ma of the electron is about —— of the ma of the hydrogen atom, and that its diameter is approximately of that of the atom of matter. From these facts it is evident that ) conskderable advances have been made in our knowledge of the nature of negative electricity, but the same cannot be said of positive electricity. The negative electron has been isolated, but not the positive electron. Hitherto the latter has always been found a ociated with an atom of matter, and diligent research has so far failed to gain much definite and exact information regard in; it, as distinguished from the atom wi which it is a ociated. It may be that in it lies the key to many of the most preplexing problems regarding the ultimate constitution of matter that still remain unsolved by science, ae Meantime, all electrical phenomena They are ascribed to the movement of neg a-| nature tive electrons. A positively charged | repelled body has lost some of its electrons; a| travel, negatively charged body has an exce . speed A continuous current in a conductor | almost te is caused olga by te <a alscon sete being ae also by the electrical pre ure to travel on Fiore een Co, Positively charged invented pelett hh aie at Ih eth: cake of their mean UN ai position, their Suge oscillations =a of same generating heat, and hence the electrons move relatively to the atoms. This mode tec ting fo tion tho constitutes mumber of electrons the current. nung The volume con of the substance; good conductors a case have a charge more electrons than bad conductors. Good both conductors of heat are in general same Se conductors of electricity. This is other. agreement with the electronic theory, | seq to according to which the ratio of the thermal to the electric positive conductivity ments should be the same for all pure metals. shows this is the case, at| Tne sa 5 for all the better conducting metals, ly used Under normal conditions gases do not conduct electricity. Conductivity may appliances be imparted temporarily to a gas by the negative following methods: (1) exposure to quantities. cathode, Lenard, or X rays; (2) exposure influence to radiations from radium or uranium; known. (3) contact with flames or hot metals; (4) circular pa age of an electric discharge. This and able temporary conductivity is due to the presence in the gas of oppositely charged tached particles called ions, and its disappear A small ance is caused by the re-combination of strips, these. The negative ions are electrons, the and there is evidence to support the induction view that the positive ions are positive charges electrons a ociated with an atom of metal matter. Other The mechanism of conduction in iquids is explained in Electrolysis.