Conductivity of Flames Containing Salt Vapors.

Conductivity of a Flame Sprayed with Salt Solutions, as a Function of the Concentration.—The method used is due to H. A. Wilson. The ratio of the potential gradients in the central parts of two flames, each about 7 cm. wide, through which the same current was passed, was determined by means of a quadrant electrometer connected alternately to each of two pairs of probe wires in the flames, by means of a rotating commutator. Both flames were sprayed with identical sprayers. When desired for greater sensitiveness the current through the flames could be increased by applying ${\mathrm{K}}_2$C${\mathrm{O}}_3$ to the cathodes. Using the conductivity produced by distilled water as a standard, the relative conductivities of various concentrations of potassium carbonate, sodium carbonate, cæsium chloride, calcium chloride, barium chloride, aluminium chloride and boric acid were determined. For the last four the conductivity was found to be approximately proportional to the cube root of the concentration, whereas in the case of the others the relation is more complicated. A theory to account for the cube root relation is suggested. The conductivities due to mixtures of two solutions were found to agree with the values computed from the conductivities due to the components alone. Uranium nitrate gave little or no conductivity.