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 of a light-giving
body measured, 51; aberration of, 199.
LIMB, the edge of the disk of the moon, sun, or a planet.
LONGITUDE. If a perpendicular be dropped from a body to the
ecliptic, its celestial longitude is the distance of the foot of the
perpendicular from the vertical equinox, counted toward the east;
mode of ascertaining terrestrial, 72.
MAGELLANIC CLOUDS, 208.
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MARS, 159; snow spots of, 160; satellites of, 161.
MASS, the quantity of matter a body contains.
MEAN DISTANCE OF A PLANET, half the sum of the aphelion and
perihelion distances.
MEASUREMENTS, celestial, 57.
MERCURY, 138.
MERIDIAN, terrestrial, of a place, a great circle of the heavens
passing through the poles, the zenith, and the north and south points
of the h