Solar month. See under Month.

Solar oil, a paraffin oil used an illuminant and lubricant.

Solar phosphori (Physics), certain substances, as the diamond, siulphide of barium (Bolognese or Bologna phosphorus), calcium sulphide, etc., which become phosphorescent, and shine in the dark, after exposure to sunlight or other intense light.

Solar plexus (Anat.), a nervous plexus situated in the dorsal and anterior part of the abdomen, consisting of several sympathetic ganglia with connecting and radiating nerve fibers; -- so called in allusion to the radiating nerve fibers.

Solar spots. See Sun spots, under Sun.

Solar system (Astron.), the sun, with the group of celestial bodies which, held by its attraction, revolve round it. The system comprises the major planets, with their satellites; the minor planets, or asteroids, and the comets; also, the meteorids, the matter that furnishes the zodiacal light, and the rings of Saturn. The satellites that revolve about the major planets are twenty-two in number, of which the Earth has one (see Moon.), Mars two, Jupiter five, Saturn nine, Uranus four, and Neptune one. The asteroids, between Mars and Jupiter, thus far discovered (1900), number about five hundred, the first four of which were found near the beginning of the century, and are called Ceres, Pallas, Juno, and Vesta.

Note: The principal elements of the major planets, and of the comets seen at more than one perihelion passage, are exhibited in the following tables: -- I. -- Major Planets. Symbol.Name.Mean distance -- that of the Earth being unity.Period in days.Eccentricity.Inclination of orbit.Diameter in miles ????????????????????? II. -- Periodic Comets. Name.Greatest distance from sun.Least distance from sun.Inclination of orbit.Perihelion passage. [deg] [min] 54 Encke's3.314.100.34212 541885.2 ?????????????????????

Solar telegraph, telegraph for signaling by flashes of reflected sunlight.

Solar time. See Apparent time, under Time.

Source: Webster's Revised Unabridged Dictionary (1913)