During dissolution of a single crystal of chiral compounds at the top a nematic droplet the correlation between the rotation direction and screw sense of the cholesteric helix was found:

1. for right-handed chiral compounds the clockwise rotation of a single crystal at the top a nematic droplet is observed in polarizing microscope [Ref.1, Ref.2] ;
   
   

2. for left-handed chiral compounds the counterclockwise rotation of a single crystal of chiral compounds at the top a nematic droplet is observed in polarizing microscope Ref.1, Ref.2] .
   
   

It was experimentally shown, that the angular velocity of the rotation of crystal of the chiral dopant dependent on:

1. the crystal dimensions;
2. helical-twisting power (β or HTP) of the dopant;
3. viscosity of the nematic solvent.

For non-chiral dopants or dissolution in isotropic solvents (or isotropic phase of nematic) no rotation was observed under the same conditions. Dissolution of a single crystal of non-chiral compounds at the nematic droplet ;

In addition, it was found, that dissolution of a single crystal of racemic mixture of enantiomers at the top a nematic droplet occurs without rotation.;

For systematic series of dopants (e.g. cholesterol esters), the angular velocity ν was:

proportional to the helical-twisting power β (HTP)

For various nematic matrices, the observed angular velocity ν was:

proportional to the rotational-viscosity coefficient γ1.

It can be argued that the obtained results:

1. suggest a novel method for the evaluation of the helical-twisting power, especially useful for dopants of weak chirality;

2. there are a direct evidence of transformation of the energy of chiral interactions into the energy of the molecular movement.