218, 220. 
APHELION, the point in an orbit farthest from the sun. 
APOGEE, the point of an orbit which is farthest from the earth. 
APSIS, plural apsides, the line joining the aphelion and
  perihelion points; or the major axis of elliptical orbits. 
ARC, a part of a circle. 
ASCENSION, RIGHT, the angular distance of a heavenly body from
  the first point of Aries, measured on the equator. 
ASTEROIDS (star-like), 162; orbits of interlaced, 74. 
ASTRONOMICAL INSTRUMENTS, 43. 
ASTRONOMY, use of, 57. 
ATOM, size of, 255; power of, 256. 
AURORA BOREALIS, 143. 
AXIS, the line about which a body rotates. 
AZIMUTH, the angular distance of any point or body in the horizon
  from the north or south points. 
BAILEY’S BEADS, dots of light on the edge of the moon seen in a
  solar eclipse, caused by the moon’s inequalities of surface. 
BASE LINE, 68. 
BIELA’S COMET, 129. 
BINARY SYSTEM, a double star, the component parts of which
  revolve around their centre of gravity. 
BODE’S LAW of planetary distances is no law at all, but a study
  of coincidences. 
BOLIDES, small masses of matter in space.  They are usually
  called meteors when luminous by contact with air, 120.
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CELESTIAL SPHERE, the apparent dome in which the heavenly bodies
  seem to be set; appears to revolve, 3. 
CENTRE OF GRAVITY, the point on which a body, or two or more
  related bodies, balances. 
CENTRIFUGAL FORCE (centre fleeing). 
CHROMOLITHIC PLATE of spectra of metals, to face 50. 
CIRCUMPOLAR STARS, map of north, 201. 
COLORS OF STARS, 214. 
COLURES, the four principal meridians of the celestial sphere
  passing from the pole, one through each equinox, and one through
  each solstice. 
COMETS, 126; Halley’s, 128; Biela’s lost, 129; Encke’s, 130;
  constitution of, 131; will they strike the earth? 133. 
CONJUNCTION.  Two or more bodies are in conjunction when they
  are in a straight line (disregarding inclination of orbit) with the
  sun.  Planets nearer the sun than the earth are in inferior
  conjunction when they are between the earth and the sun; superior
  conjunction when they are beyond the sun. 
CONSTELLATION, a group of stars supposed to represent some figure: 
  circumpolar, 201; equatorial, for December, 202; for January, 203;
  April, 204; June, 205; September, 206; November, 207; southern
  circumpolar, 208. 
CULMINATION, the passage of a heavenly body across the meridian
  or south point of a place; it is the highest point reached in its
  path. 
CUSP, the extremities of the crescent form of the moon or an
  interior planet. 
DECLINATION, the angular distance of a celestial body north or south
  from the celestial equator. 
DEGREE, the 1/360 part of a circle. 
DIRECT MOTION, a motion from west to east among stars.