The following expression is proposed for the electrical conductivity of silver bromidekhgr;equals;lpar;Aeminus;Wsol;2kTplus;KSrpar;eminus;Usol;kT,in whichSis the magnitude of the active surface. WhenAeminus;Wsol;2kTGt;KSthe high temperature kind of conductivity predominates. In the opposite case the low temperature kind of conductance predominates. Conductivityhyphen;temperature curves of fresh (largeS) and wellhyphen;aged (smalls) silver bromide have been determined. In agreement with theoretical expectations it is found thatkhgr;equals;3.0times;105eminus;18,000sol;RTplus;Aieminus;8300sol;RTin whichAivaries in proportion to the active surface of the product. A pellet prepared from freshly precipitated silver bromide was found to have about 500 times as large a conductance as a pellet prepared from the fused product. At a given temperature the following relation exists between khgr; and the pressurepapplied to the pellet:dlnkhgr;sol;dpequals;minus;k. The value ofkincreases with decreasing active surface and with increasing temperature. The temperature effect is accounted for by the contribution of the active surface.
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