XI. IMAGINATION AND REALITY
XII. OROGRAPHICAL DETAILS
XIII. LUNAR LANDSCAPES
XIV. A NIGHT OF THREE HUNDRED AND FIFTY-FOUR HOURS AND A HALF
XV. HYPERBOLA OR PARABOLA
XVI. THE SOUTHERN HEMISPHERE
XVII. TYCHO
XVIII. GRAVE QUESTIONS
XIX. A STRUGGLE WITH THE IMPOSSIBLE
XX. THE SOUNDINGS OF THE SUSQUEHANNA