If they belong to uniaxial crystals they show a dark cross or convergent light between crossed nicols, the bars of which remain parallel to the wires in the field of the eyepiece.
2.
The earliest reference to the use of " conoscopy " ( i . e ., observation in convergent light with a polarization microscope with a Bertrand lens ) for evaluation of the optical properties of chiral-nematic phases.
मोबाइल