Parincic Angle, we Angle of Structur Paralostic Inequality of the Moca. See F72 Puramaz Tesariais, a coat ge; a word vary aggued in atriecay. See P. 245. Paraliaz, Erustorial horizontal, of the ben or Mons, is the greatest angle subtended by the Earth's equatorial wu. Gazeter at the dun or at the Mxa. Paralds of Declination cognate to Paraax, in the idea of rows or strata are smail circles paraue to the celestial equator. Penumbra pene almost, and umbra a shadow; the pale shade which encom passes the dark shadow of the Earth in an ecupee of the Moon. Perigee (rep near, the Earth); the converse of apogee (q. v.) Perihelion (rep near, and for the Sur); the converse of aphelion (q. v.) Perihelion distance; the least distance of a planet or comet from the Sun, usually expressed in semi-diameters of the Earth's orbit. Symbol, q. Sadalmelik, a star otherwise called a Aquarii. Sadalsund, a star otherwise called 8 Aquarii. Satellite (satelles, a companion); the orthodox name for what are often called moons and secondary planets; namely, the little bodies which revolve round certain of the major planets. Saturnicentric (Saturn, and Kévτρov a centre); as viewed from, or having relation to, the centre of Saturn. Scheat, a star otherwise called 8 Pegasi. Schedar, a star otherwise called a Cassiopeix. Scintillation (scintilla, a spark); a fastidious word applied to what everybody knows as the twinkling of the stars. Secondary Planet. See Satellite. applied to some inequality, the period of which depends on very small variations in the elements of the orbit. Secunda Giedi, a star otherwise called a2 Capricorni. Selenocentric (reλhvn the Moon, and I describe), the branch of astronomy which treats specially of the Moon. Semi-diurnal arc is the half of the arc described by any heavenly body between its rising and setting. Sextant (sextans, a sixth part); a wellknown nautical instrument, so-called because its arc is the sixth part of a circle. See p. 664. Sheliak, a star otherwise called B Lyræ. Sheratan, a star otherwise called ẞ Arietis. Sidereal (sidus, a constellation); having relation to the stars. Sirius, a star otherwise called a Canis Majoris; the brightest star in the heavens. Anciently and often called the Dog-star. Solar (sol, the Sun); having relation to the Sun. Solstices (sol the Sun, and stare to stand still) are the two periods when the Sun reaches the northernmost and southernmost points of the ecliptic, so called because for a few days its latitude does not seem to vary. The former is called the summer and the latter the winter solstice by the inhabitants of our hemisphere. Solstitial colure; the colure (q.v.) passing through the two solstitial points whose longitudes are 90° and 270° respectively. Sothiac Period; a period of 1460 years, at the completion of which, in consequence of the Egyptian year being taken at 365 days exactly, the days of the month return to the same seasons of the year. Spica, a star otherwise called a Virginis. Stationary points of a planet's orbit are those points at which the planet appears to us to have no motion amongst the stars. Sulaphat, a star otherwise called y Lyræ. Symbols (oupBoλov, a token) are signs constantly used by all scientific men as abbreviations in writing, to save the constant repetition of the same words and phrases. I here give the astronomical and some of the chief mathematical ones: a Arago. , and, the signs of Libra, Aquarius, and Pisces a. M Mean anomaly. A or L Mean longitude at epoch. Longitude of the perihelion. Angle of eccentricity. ← Eccentricity (= Nat. sin. of p). μ Direction and velocity of mean motion in seconds of time. a Semi-axis major, or mean distance. T, 7, or PP Time of perihelion passage. q Distance from Sun when in perihelion. r Length of radius vector. A Distance of the planet or comet from the Earth. Degree. Minute of arc. " Second of arc. ""Third of arc. [obsolete.] nf. North-following. sf. South-following. sp. South-preceding. np. North-preceding. Pos. Angle of position (of double stars). Dist. Distance of two stars in seconds of arc. LUNAR MOTIONS. Moon in conjunction, or new. Moon at eastern quadrature, or first quarter. Moon in opposition, or full. Moon at western quadrature, or last quarter. MATHEMATICAL. Minus; sign of subtraction. + Plus; sign of addition. Sign of multiplication. + Sign of division. Synodical (our with, and ddós a journeying). Syzygy (our with, and (vyóv a yoke); the conjunction and opposition of the Moon are both termed indifferently a U. Ultra-zodiacal (ultra beyond, and zodiac); beyond the limits of the zodiac. A term sometimes applied to the minor planets, because their orbits (or at least many of them) reach beyond the zodiac. Umbra (umbra, a shadow); the shadow of the Earth, Moon, or any other planet, is in particular so called. Unukalhay, a star otherwise called a Serpentis. Uranography (oupavós the heavens, and Ypápa I describe); that branch of astronomy which treats specially of the heavens. V. Vega, a star otherwise called a Lyræ: sometimes spelt Wega. Via Lactea, the Latin word corresponding to the Greek 'Galaxy' and the English 'Milky Way.' Vindemiatrix, a star otherwise called € Virginis. Volume (volumen, bulk) of a planet or comet is its cubical content, expressed either absolutely as so many cubic miles, or relatively as such and such a fraction of the Sun or some planet. W. Wasat, a star otherwise called 8 Gemi norum. Z. Zaurac, a star otherwise called y1 Eridani. Zavijara, a star otherwise called B Virginis. Zodiac (úvn, a girdle); a belt of the heavens extending 9° on either side of the ecliptic, in which the Sun, Moon, all the major and many of the minor planets perform their annual revolutions. Zosma, a star otherwise called & Leonis. Zubenelg, a star otherwise called a2 Libræ, INDEX OF SUBJECTS. This Index is designed for use in connexion with the Table of Contents. It is Atmosphere, refraction of, 250; lunar, Auriga, 556. Aurora Borealis, and spots on the Sun, 15, Baily's beads, 175. Barometer, use of, in determining refrac- tion, 252. Beatrix, 96. Belgrade, siege of, 314. Bellona, 92. Belts of Jupiter, 105; of Saturn, 122. Bible allusions to comets, conjectured, Bible, references to-- Gen. i. 435- i. 5 471. i. 14 471. viii. 22 237- Exod. xii. 18. 452. |