CHAPTER IV. SPHERICAL COÖRDINATES. Section I. General Theory. II. Problems and Applications of the Theory of Spherical Coördinates.
CHAPTER V. THE MEASURE OF TIME AND RELATED PROBLEMS. Section I. Solar and Sidereal Time. II. The General Measure of Time. III. Problems Involving Time.
Mars and Its Canals · The Wunder Library — complete classics, free to read, with narration.