Effulgent, sending forth a flood of light; as the effulgent orb of day. (ef for ex, forth.)
Incandesco, to become white. (L.) Hence,
Incandescent, glowing with a white heat. When a bar of iron is heated it first becomes red, and, as the heat increases, it becomes incandescent.
Luster, brightness; as, the luster of the sun; the luster of silk; the luster of a great name.
Lustrous, 1. Bright, Good sparks and lustrous.—Shakspeare. 2. Glossy; as, lustrous locks.
Illustrate, lit, to add luster or brightness. Hence, to make clear or intelligible by means of comments, examples, or pictures. (Il for in, upon.)
Illustrious, brightened with the splendor of high rank, or of great and noble achievements; as, an illustrious prince.
Radius, the spoke of a wheel. (L.) Hence,
Ray, (contraction of radius,) a single line of light; because rays diverge from a luminous point like spokes from the hub of a wheel.
Radiate, to send forth rays.
Radiation, the act of sending forth rays.
Radiant, sending forth copious rays; as, the radiant sun.
Radiance, or Radiancy, vivid brightness, caused by radiation from a copious source of light.
Irradiate, to overspread an object or scene with rays of light, [ir for in, upon.)
ΦΩΣ [PHOS], light. (Gr.) Hence,
Phosphor, the Morning Star. (Gr. φερω [phero], to bear.)
Phosphorus, a chemical element, so called from the readiness with which it is rendered luminous by friction.
Phosphorescent, shining with inherent light, without sensible heat. Decayed wood is sometimes phosphorescent.
Photography, the art of forming pictures by means of light. (Gr., γραφω [grapho], to draw, or delineate.)
Photometer, an instrument for measuring the intensity of light. (Gr., μετρεω [metreo], to measure.)
To Wane, is to decrease in brightness. The moon wanes nightly after the full.
To Tarnish, is to diminish the luster, as that of a piece of burnished silver.
Note.—Metals tarnish by oxydation. See Art. Chemistry.
A Beam is a body of parallel rays.
A Pencil is a body of rays that either converge or diverge.
A Focus is the common point to which rays converge, or from which they diverge.
A Rainbow is an arch of variously colored light, formed by the action of falling drops of rain upon the sun's rays.
A Halo is a luminous circle which sometimes surrounds the sun or the moon.
Note.—The halo is supposed to be caused by the action of small crystals of frozen vapor upon the rays of the sun or moon.
A Corona is a small luminous circle surrounding the sun or the moon.
Note.—The corona is caused by the action of small particles of watery vapor upon the light of the sun or moon. (L., corona, a crown.)
A Glory is a halo surrounding the head of the Savior in pictures.
A Parhelion, or Mock-sun, is a luminous appearance resembling the sun, which is sometimes seen on the circumference of a solar halo.
Note.—Two parhelia are usually visible at the same time, horizontally opposite to each other. (Gr. παρα [para], near; and ήλιος [helios], the sun.
Lightning consists in the evolution of light by the rapid passage of a body of the electric fluid through the air.
A Meteor is a luminous body either floating in, or flying rapidly through the air, or above it. (Gr μετεωρος [meteoros], elevated.
Shooting Stars, Bolides, or Fire-balls, are luminous bodies which
