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LI. Some Applications of the Electron Theory of Matter. By 

 0. W. Richardson, Professor of Physics, Princeton 

 University *. 



§ 1. A LTHOUGrH parts of this paper may appear to be 

 JTjl disconnected it is, on the whole, a development 

 along the direction suggested by a recent communication to 

 this Journal f. § 2 gives the results of an investigation 

 undertaken to obtain information about the law of force which 

 governs the col isions of electrons in metals. After I had 

 finished this part of the investigation I found that formulae 

 identical with tnose obtained had already been published in a 

 Danish dissertation by Niels Bohr J. As, however, Bohr's 

 mathematical methods appear to be different from those which 

 I have used, I have thought that a brief account of my calcu- 

 lations might prove to be of interest. § 3 contains a thermo- 

 dynamic calculation of the electronic pressure outside a metal 

 which brings the electronic emission into relation with 

 thermoelectric phenomena. § 4 deals with the reflexion of 

 the electrons which strike the surface of a body under con- 

 ditions of thermal equilibrium and, by making use of statistical 

 principles, deduces certain laws which have to be satisfied by 

 such reflexion. § 5 is a further development of the theory of 

 thermoelectric phenomena. The main point is that there is 

 not necessarily any simple relation between thermoelectric 

 effects and the free electrons which determine the electrical 

 conductivity. § 6 discusses the role of "polarization" electrons 

 in electrical conduction, largely from the point of view of the 

 way in which galvanomagnetic phenomena may possibly be 

 affected thereby. § 7 deals with the application of thermo- 

 dynamics and statistical principles to the aethereal radiation 

 and photoelectric effects. The close similarity between 

 thermionic emission and the photoelectric emission arising 

 from the complete ^ethereal radiation is brought out. Some 

 of the consequences of theories of the photoelectric effect of 

 the type of Einstein's are analysed. Finally certain equations 

 are deduced which have to be satisfied by the functions which 

 represent the distribution of velocity among the electrons 

 given out under the action of light of a given frequency and 

 otherwise of definite specification. Some of the results of 

 this section are strictly true only for types of matter having 

 rather restricted properties. The limitations thus introduced 

 are considered. ^L- 



* Communicated by the Author. ^ 



f Richardson, Phil. Mag. [6] vol. xxiii. p. 263 (1912). 

 1 " Studier over nietallernes Elektronentheori." Afhandlung for den 

 ilosohske Doktorgrad af Niels Bohr. Copenhagen, 1911. 



