I. Creative Processes.—­The dial-plate of the sky.  Cause or different weights—­on sun, moon.  Two laws of gravity.  Inertia.  Fall of earth to sun per second.  Forward motion.  Elastic attraction.  Perturbation of moon; of Jupiter and Saturn.  Oscillations of planets.

II. Light.—­From condensation.  Number of vibrations of red; violet.  Thermometer against air.  Aerolite against earth.  Two bolides against the sun.  Large eye.  Velocity of light.  Prism.  Color means different vibrations.  Music of light.  Light reports substance of stars.  Force of; bridge, rain, dispersion, intensities, reflection, refraction, decomposition.

III. Astronomical Instruments.—­Refracting telescope.  Reflecting; largest.  Spectroscope.  Spectra of sun, hydrogen, sodium, etc.  E made G by approach; C by departure.  Stars approach and recede.

IV. Celestial Measurements.-Place and time by stars.  Degrees, minutes, seconds.  Mapping stars.  Mural circle.  Slow watch.  Hoosac Tunnel.  Fine measurements.  Sidereal time.  Spider-lines.  Personal equation.  Measure distance—­height.  Ten-inch base line.  Parallax of sun, stars.  Longitude at sea.  Distance of Polaris, a Centauri, 61 Cygni.  Orbits of asteroids.

V. The Sun.—­World on fire.  Apparent size from planets.  Zodiacal light.  Corona.  Hydrogen—­how high?  Size.  How many earths?  Spots:  1.  Motion; 2.  Edges; 3.  Variable; 4.  Periodic; 5.  Cyclonic; 6.  Size; 7.  Velocities.  What the sun does.  Experiments.

VI. The Planets from Space.—­North Pole.  Speed.  Sizes.  Axial revolution.  Man’s weight on.  Seasons.  Parallelism of axis.  Earth near [Page 277] sun in winter.  Plane of ecliptic.  Orbits inclined to.  Earth rotates.  Proof.  Sun’s path among stars.  Position of planets.  Motion—­direct, retrograde.  Experiments.

VII. Meteors.—­Size; number; cause of; above earth; velocity; colors; number in space; telescopic view of.  Aerolites:  Systems of; how many known.  Comets:  Orbits; number of comets; Halley’s; Biela’s lost; Encke’s.  Resisting medium.  Whence come comets?  Composed of what?  Amount of matter in. [Symbol].

VIII. The Planets.—­How many?  Uranus discovered?  Neptune?  Asteroids?  Vulcan?  Distance from sun.  Periodic time.  Mercury:  Elements; shapes, as seen from earth; transits.  Venus:  Elements; seen by day; how near earth? how far from? phases; Galileo.  Earth:  Elements; in space; Aurora; balance of forces.  Tides:  Main and subsidiary causes; eastern shores; Mediterranean Sea.  Moon:  Elements; hoax; moves east; see one side; three causes help to see more than half.  Revolution:  Why twenty-nine and a half days:  heat—­cold; how much light?  Craters and peaks lighted; measured.  Eclipses—­Why not every new and full moon?  Periodicity.  Mars:  Elements; how near earth?  How far from?  Apparent size; ice-fields; which end most?  Satellites—­Asteroids:  How found?  When?  By whom?  How many?  Jupiter:  Elements; trade-winds; how much light received?  Own heat.  Satellites:  How many?  Colors.  Saturn:  Elements; habitability; rings; flux; satellites.  Uranus:  Elements; discoverer; seen by; moon’s motion.  Neptune:  Elements; discovered by; how?  Review system.