20. Relative sizes of orbits of planets.
19. A view of the universe. (Copyright)
18. Earth's true orbit and sun's apparent path.
17. Celestial sphere, showing equator and ecliptic. (Copyright)
16. Path of sun among the stars, May 15 to July 14.
15. Seasonal change in sun's altitude—Stonehenge. (Copyright)
14. Path of moon among the stars, Feb. 20-26, 1926.
13. Gyro-compass—depends on rotation of earth.
12. Results of experiments—two circles, indistinguishable.
l l. Does earth or sky rotate? Apparatus for experiments.
