Recent transference-cell e.m.f. data sets for various 1:1 electrolytes in aqueous-organic solvent mixtures obtained in these laboratories for the determination of ionic transference numbers have been aggregated with earlier sets for 1:1 electrolytes in aqueous solutions and reexamined in the light of a new theoretical approach accounting for the solvent transfer phenomena accompanying ionic transfer. The potentialities and the precision of the transference-cell e.m.f. method have been highlighted, and new salt bridges, for use in aqueous-organic solvents, have been thereby characterized.