  The present work contains results of experimental investigation of external
factors, such as dessicating/wetting, thermal annealing, uniaxial and
hydrostatic pressures on dielectric permittivity of Rochelle salt crystals. The
obtained results are compared with available literature data. A conslusion is
made that the dispersion of experimental data can be attributed to internal
polar point defects in crystals and to influence of storage conditions. The
obtained results are analyzed within the phenomenological Landau approach.
