DISK, the visible surface of sun, moon, or planets. 
DISTANCE OF STARS, 70. 
DOUBLE STARS, 210. 
EARTH, revolution of, 109; in space, 142; irregular figure, 145. 
ECCENTRICITY OF AN ELLIPSE, the distance of either focus from centre
  divided by half the major axis. 
ECLIPSE (a disappearance), 157. 
ECLIPTIC, the apparent annual path of the sun among the stars;
  plane of, 106. 
EGRESS, the passing of one body off the disk of another. 
ELEMENTS, the quantities which determine the motion of a planet: 
  data for predicting astronomical phenomena; table of solar, 274. 
ELEMENTS, chemical, present in the sun, 270. 
ELONGATION, the angular distance of a planet from the sun. 
EMERSION, the reappearance of a body after it has been eclipsed or
  occulted by another.
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EQUATOR, terrestrial, the great circle half-way between the poles of
  the earth.  When the plane of this is extended to the heavens,
  the line of contact is called the celestial equator. 
EQUINOX, either of the points in which the sun, in its apparent
  annual course among the stars, crosses the equator, making days
  and nights of equal length. 
EVOLUTION, materialistic, 182; insufficient, 189. 
FIZEAU determines the velocity of light, 23. 
FORCES, delicate balance of, 144. 
GALILEO, construction of his telescope, 43. 
GEOCENTRIC, a position of a heavenly body as seen or measured from
  the earth’s centre. 
GEODESY, the art of measuring the earth without reference to the
  heavenly bodies. 
GOD, relation of, to the universe, 258. 
GRAVITATION, laws of, 6; extends to the stars, 13; theories of, 253. 
GRAVITY on different bodies, 6, 274. 
HELICAL, rising or setting of a star, as near to sunrise or sunset
  as it can be seen. 
HELIOCENTRIC, as seen from the centre of the sun. 
HOOSAC TUNNEL, example of accuracy, 62. 
HORIZONTAL PENDULUM, 272. 
IMMERSION, the disappearance of one body behind another, or in
  its shadow. 
INCLINATION OF AN ORBIT, the angle between its plane and the plane
  of the ecliptic. 
INFERIOR CONJUNCTION, when an interior planet is between the earth
  and the sun. 
JUPITER, apparent path of, in 1866, 112; elements of, 164;
  satellites of, 165; positions of satellites, 166; elements of satellites,
  166; the Jovian system, 167. 
KEPLER’S LAWS—­1st, that the orbits of planets are ellipses, having
  the sun or central body in one of the foci; 2d, the radius-vector
  passes over equal spaces in equal times; 3d, the squares of the
  periodic times of the planets are in proportion to the cubes of
  their mean distances from the sun. 
LATITUDE, the angular distance of a heavenly body from the ecliptic. 
LIGHT, the child of force, 17; number of vibrations of, 18, 25;
  velocity of, 22; undulatory and musical, 26; chemical force of, 30;
  experiments with, 37; approach and departure