Nature, Shape, and Size of the Earth—The Polar       67-123 Compression and Equatorial Protuberance, and their Cause—The Attraction of Gravitation—The Mass of the Earth: how Found—How the Earth Holds the Moon, and the Sun the Planets—The Tides—How the Moon and Sun Produce Tides—Spring Tides and Neap Tides—The Atmosphere—The Law and Effects of Refraction—Dip of the Horizon—The Aberration of Light—Time: how Measured—Sidereal, Apparent Solar, and Mean Solar Time—The Clock and the Sun—Day and Night—Where the Days Begin—The Seasons—Effects of the Varying Declination of the Sun—Polar and Equatorial Day and Night—The Tropics and the Polar Circles—Inequality of Length of the Seasons—When the Seasons in the Two Hemispheres will be Reversed—The Calendar, the Year, and the Month—Reformations of the Calendar—Different Measures of the Month