Enantiomers exhibit opposite optical activities but identical Faraday rotations. We demonstrated that the corresponding meso molecules, whose optical activities vanished because of an internal compensation, exhibited Faraday rotations different from their chiral diastereoisomers. In the case of tartaric acid, the excess of Faraday rotation compared to a water-filled reference cell, and measured using a differential method, was two times greater for the meso than for the chiral isomers. This result was in agreement with a theoretical model based on the dipole-dipole interaction model, which took into account the applied magnetic field. (c) 2005 Elsevier B.V. All rights reserved.