The layer compression modulus was observed near the smectic-A-smectic-Co phase transition in a chiral smectic liquid crystal. The layer compression modulus B shows marked pretransitional effects above the phase transition. These effects clearly show that the transition is not of the Landau mean-field type. The temperature dependence of B clearly defined the smectic-A-smectic-Cα* phase transition temperature and supplied a piece of new and clear evidence that the smectic-Cα* phase is a tilted phase.
