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In a metal of conductivity σ the electric current density, J, is related to the electric field, E, through J=σE. In the case of a cubic metal (such as the alkalis or group IB metals) G is a scalar and the current everywhere follows the lines of electric field. When a magnetic field is applied, the Lorentz force qv x H/c acts on the charge-carriers q (usually electrons) tending to displace the lines of current flow. The initial displacement of current flow generally gives rise to an electric field tending to oppose further displacement; this electric field is the Hall …
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All "transport" phenomena in solids (electrical and thermal conductivity, thermoelectricity, etc.) are described ultimately in terms of the mean free path for scattering. Conductivity measurements essentially give the magnitude of the mean free path, and thermoelectric power its variation with energy. Size effect measurements can give very direct information about the mean free path and recent experiments in this laboratory by White and Woods have extended earlier measurements on electrical conductivity (MacDonald and Sarginson: Nature, 163, 637; 164, 920 (1949) : Proc. Roy. Soc. A 203, 223 (1950)) to thermal conductivity and promise information of considerable interest on the thermal …
