Optically active, Optically inactive (Chem. Physics), terms used of certain isomeric substances which, while identical with each other in other respects, differ in this, viz., that they do or do not produce right-handed or left-handed circular polarization of light. See optical activity.
Optically positive, Optically negative. See under Refraction.
... corona" to the height of 5' or 6' from the limb was admitted; but it was supposed that by the detailed reflection of its light in our air the far more extensive "outer corona" was optically created, the irregularities of the moon's edge being called in to account for the rays and rifts by which its structure was varied. This view received some countenance from Admiral Maclear's observation, during the eclipse of 1870, of bright lines "everywhere"—even ... — A Popular History of Astronomy During the Nineteenth Century - Fourth Edition • Agnes M. (Agnes Mary) Clerke
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