AURA n.
The peculiar sensation, as of a light vapor, or cold air, rising from the trunk or limbs towards the head, a premonitory symptom of epilepsy or hysterics. Electric ~, a supposed electric fluid, emanating from an electrified body, and forming a mass surrounding it, called the electric atmosphere. See Atmosphere, 2.…
AXIS n.
ion of a girder. -- Optic axis of a crystal, the direction in which a ray of transmitted light suffers no double refraction. All crystals, not of the isometric system, are either uniaxial or biaxial. -- Optic axis, Visual axis (Opt.), the straight line passing through the center of the pupil, and perpendicular to the…